Immunology MCQS

Final

Chapter 1

Functions and types of immune cells

neutrophils (PMN)
basophils
eosinophils
monocytes
macrophages (EC pool, resident in tissue)

Alveolar (lung)
Kupffer (liver)
Mesangial (kidney)
Microglial (brain)
Osteoclast (bone)

dendritic cells (bone marrow derived)
T lymphocytes (thymus derived)
B lymphocytes
NK cells

Lymphocytes or T cells and B cells

1. Characteristics of T lymphocytes

originate in red bone marrow
differentiate in thymus
primarily located in lymphatic tissues
make up 70~80% of circulating lymphocytes
provide cellular immune response

2. Roles of B cells

mainly involved in antibody production
develop into plasma or memory cells in bone marrow
present antigen to T cells
recognition of antigen through surface receptors (antibodies)

5. Roles of T cells

cell-mediated immunity
provide protection against infection
acquire ability to distinguish self and non-self (graft rejection)
Th activate B cells to make antibodies, activate macrophages
CTL kill infected cells and tumor cells
regulatory T regulates immune response, maintain tolerance
NK attack and kill target cells, ADCC
memory T

Lymphoid organs

1. Primary: sites of development and maturation of lymphocytes

thymus: development of immature TL into mature TL

bone marrow: development of pluripotent stem cells into mature cellular components of blood

2. Secondary

spleen: filter of blood, antigen trap of blood, main site for destruction of RBCs and platelets, red pulp (removal of WBC and RBC), white pulp (immune response)

lymph nodes: filter of lymph, immune cells trap germs, activate creation of special antibodies in blood, presence of secondary follicles with germinal centers indicates an ongoing immune response

3. Major functions of secondary lymphoid organs

residence for a variety of lymphoid cells
traps for antigen
anatomical site in which immune responses are initiated

Chapter 2

Innate immunity

1. Characteristics

present at birth
non specific
no memory
limited diversity

2. Mechanism of innate immunity

3. Intrinsic epithelial barriers to infection

mechanical

epithelial cells joined by tight junctions
longitudinal flow of air of fluid across epithelium
movement of mucus by cilia

chemical

fatty acids (skin)
low pH (stomach)
enzymes: lysozyme (saliva, sweet, tears), pepsin (gut)

microbiological

NF compete for nutrients, attach to epithelium, produce antibacterial substances

4. Symptoms of inflammation

redness: increased blood flow to infected area
pain: stimulation of pain receptors by kinins, injury of nerve fibers, irritation by toxic chemicals released by microbes
heat: large amount of warm blood flowing to the area, increased metabolic activities
swelling: increase in permeability of capillaries permits more fluid to move from blood into tissue spaces

5. Major physiological events during inflammatory response

Vasoconstriction refers to the constriction of blood vessels leading to decreased blood flow to a part.
Vasodilation refers to the increased volume of blood flow to the site.
Decreased velocity of blood flow to the site allows leukocytes to slow down and adhere to the vascular endothelium.
Increased expression of vascular endothelial adhesion molecule allows leukocytes to attach to the vascular endothelium.
Increased vascular permeability allows fluid to enter the tissues.
Influx of phagocytic cells into tissues due to increased margination and extravasation.

Biological features

6. Phagocyte functions

recognition of microbes (pattern recognition)
synthesis and secretion of cytokines/chemokines
phagocytosis (bind and engulf particles)
intralysosomal digestion and killing of ingested material
chemotaxis (migration toward a chemoattractive signal)

Phagocytosis

Phagocyte killing mechanisms

7. Complement activation

Complement is a group of approximately 25 plasma proteins. It can be activated by:

IgG or IgM with immunogen complexes
Bacterial cell wall and toxins
Pharmacological effect (release of lysosomal enzymes)
Proteolytic activity, chemotactic, opsonization, cellulolysis

8. Vasoactive substance: initial acute inflammation, wide distribution in mast cells, CT (mammary gland, tongue, prostate, GIT, RT, serous membrane, in skin)

Vasoactive substances can be released by several mechanism include:

Mechanical disruption and lysis of cells
Lysosomal substances from neutrophils
Activated complement component (C3a)
IgE-allergen complexes

There are examples of vasoactive substances include:

Histamine stimulates vasodilation and increased capillary permeability.
Kinins causes vasodilation and increased permeability.
Prostaglandins increases vasodilation and vascular permeability. It also serves as chemoattractant for neutrophils.
Leukotrienes increase smooth muscle contraction and serve as chemoattractant for neutrophils.

Cytokines

Chemotaxis

9. Therapeutic use of cytokines

interferon: viral ds, cancer tx
IFN𝛾, TNF⍺ and IL-2: T cell activation
IL-2 and lymphokine: activate killer cells in tx of cancer
restore leukocytic count after cytotoxic chemotherapy induced neutropenia
correct AIDS-associated leukopenia
anti-TNF: rheumatoid arthritis tx, septic shock
anti-IL2: reduce graft rejection and adult T cell leukemia
anti-IL4: allergies under trial tx

10. Benefits of inflammatory response

Inflammatory response is rapid and may stop further progression of the disease. Inflammatory response prevents the spread of pathogens. Inflammatory response localizes and restricts damage at affected site. Inflammatory response restores tissue function at the proinflammatory level. It allows healing to begin.

Chapter 3

Adaptive immunity

1. Characteristics

actions requires days to develop
response is specific
response is enhance on repeated
exposure to pathogen

2. Examples of active and passive acquired immunity

naturally acquired active: infection
artificial active: vaccine (initial exposure to specific foreign macromolecules)
natural passive: breastmilk (maternal antibodies)
artificial passive: antiserum (monoclonal)

Monoclonal antibody

homogenous antibody population produced by single clone of plasma B cell
interact with particular epitope
expensive to produce

Polyclonal antibody

heterogenous antibody population produced by multiple clones of plasma B cells
interact with different epitope on the same antigen
less expensive to produce

First line defense

Second line defense

phagocytes
NK
acute phase proteins
complement
cytokines
lysozyme

Third line defense ( B T antibodies cytotoxicity)

characteristic: specificity, diversity, memory, self/non-self

Humoral immunity: synthesis of specific molecules by B cells (antibody) which are subsequently found in body fluids (blood and lymph fluid)

Cell mediated immunity: involves activation of T cells, neutrophils, macrophages and CTL

1. Mechanism of cell-mediated immunity activation after exposure of endogenous organisms

2. Process of humoral immunity production

3. Distinguish between T dependent and T independent antigens

T dependent: T activate B

Th stimulate B to plasma
proteins on virus, bacteria, foreign materials, glyco/lipoprotein
simplex
memory present
antigen processing
rapidly metabolized
require Th

T independent: B activate without T

lipopoly/polysacchrides with repeating subunits
complex
immune response induce IgM production/low affinity for antigens
no memory
no antigen processing
slowly metabolized
do not require Th

4. Exogenous antigen: foreign compound enter body from outside

Phagocytosis of antigen
Digestion of antigen into peptide fragments
Synthesis of MHC molecules
Fusion of vesicles
Binding of peptide fragments to MHC molecules
Insertion of antigen-MHC complex into plasma membrane

5. Endogenous antigen: compound generated within cell

6. Maturation of B and T cells/Lymphocyte development

Both cells develop from pluripotent stem cells of red bone marrow. T cells mature in thymus. B cells develop in red bone marrow through life. Both disperse to the lymph nodes and spleen. Both cells develop immunocompetence.

Immunocompetence: ability to carry out immune response

Immunogenicity: ability to provoke immune response by stimulation production of specific antibodies and proliferation of specific T cells

Reactivity: ability of antigen to react specifically with antibodies or cells it has provoked

Epitope: a small part of a large antigen which acts as trigger for immune response

Hapten: a smaller substance with reactivity but lacks immunogenicity

Chapter 4 Antibody

1. IgG monomer (80~85%)

can cross placenta
smallest Ab
found in all body fluids, colostrum
responsible for protection of newborn
secondary immune response

2. IgM pentamer (5~13%)

first Ab secreted by B
largest Ab
found in blood, lymph fluid
responsible for neutralize Ag and controls bloodstream infection
primary immune response
can bind to B cell surface

3. IgA dimer (10~13%)

produced in mucous lining, found in mucous secretions
prevents colonization by pathogens
2 subclasses: IgA1, IgA2
present in large quantities in breast milk

4. IgE monomer

found in mammals
defends against parasitic invasion
responsible for allergic reactions
mediates release of histamine and heparin

5. IgD monomer (1%)

produced in secreted form in small amount
unknown functions
can bind to B cell surface

6. Mechanism of antibody production and it's importance

presentation of antigen to, and stimulation of antigen-specific CD4 T cells to proliferate and differentiate into Th
stimulation of B cells by antigen and interaction with Th
proliferation of B cells and their differentiation into plasma or memory cells

7. Activation of CD4 Th during earlier stages of antibody production (0~5 days)

stimulation of CD4 T into Th at lymph nodes and spleen

delivery of antigen to lymph nodes or spleen

tissue infected by microbes
dendritic cells take up antigen by phagocytosis
leave infectious site and migrate to lymph nodes
process antigen results in expression of class II MHC on surfaces for recognition by CD4 T at lymph nodes
spleen deal with blood pathogens

activation of antigen-specific CD4 T cells

CD4 T able to recognize and respond to as few molecules of antigen or class II MHC as possible
initiation of response
involves interaction of FcR (Fc receptor) on CD4 T cell surface with class II MHC on APC (dendritic cell) and the reaction of co-stimulus as well

proliferation of activated CD4 T cells and differentiation into Th

proliferation of CD4 T is driven by cytokines (IL-2)
peaks 3~4 d after initial contact with antigen, results in 10,000~100,000-fold increase
differentiation
Th move to cortex in lymph nodes and interact with B cells

8. The way B cells are stimulated by antigen and their interaction with helper T cells in lymph nodes during antibody production process

antigen filtering thro lymph node cortex captured by macrophages

if antigen on macrophage comes into contact with B cells:

B cell take up antigen, process into class II MHC or antigen complex

activated B cells interact with Th cell through their TcR (T cell receptor)
Th will be stimulated and produce cytokines

some B cells differentiate into plasma cells secreting IgM

some more undergo class switch to IgG and differentiate into IgG-secreting plasma cells

after 4~7 d, some B cells and Th cells migrate to primary follicles to form germinal center

9. Events that occur in germinal centers during antibody production (4~14 days)

antibody class switch

B cell is able to change the heavy chain constant region, thus change Ig class
class switch is controlled by cytokines and Th
cytokines affect the level of antibody production by plasma cells

affinity maturation of antibody

high affinity of antibody is produced
due to hyper-maturation of heavy and light chain
amino acid sequence is changed
conformation of antigen binding site is changed
high affinity increase survival rate

differentiation of B cells into memory B cells

provide protection against future infection
long-lived, can survive long after an initial infection has been eliminated
enter recirculating lymphocyte pool and migrate thro lymph nodes, spleen, some other lymphoid tissue
encounter antigen, develop into plasma cells, secrete high affinity IgG, A, E
no need to undergo affinity maturation and class switch again

differentiation of B cells into plasma cells

secrete large amount of antibody
short or long-lived
some in lymphoid tissues
others migrate to bone marrow, interact with stromal cells

Stages of antibody production in lymphoid organs

Chapter 5

1. Antigen processing and presentation in MHC class I and II/Antigen recognition

endogenous antigens are produced within the cells
are processed and presented by MHC class I
proteosomes have proteolytic activity and are able to degrade protein into peptide fragments
TAP transporter transport peptide fragments from cytoplasm to RER
presence of antigenic peptide is expressed on all cell surfaces of nucleated cells
presented to CD8 T cells

exogenous antigens are derived from outside the cell
are processed and presented by MHC class II
extracellular proteins are endocytosed and degraded in lyososomes
fuses with lysosomes to form endolysosome
presence of antigenic peptide is expressed on APC
presented too CD4 T cells

Chapter 6 Antibody-mediated response

1. Neutralization

toxins

bind to them
inhibit their action
tetanus, diphtheria

virus

antibody can bind to viral receptor molecule
stop it binding to cell
prevent infection
prevent replication of virus
measles, influenza

bacteria

antibody can affect bacterial adherence to cells
inhibit their metabolism
mucosal IgA can bind cholera bacteria, prevent adherence to intestinal epit

2. Agglutination

antibodies are multivalent
able to bind more than 1 microbial particle
form complex
limit spread of pathogens by retaining them in clumps
larger complexes of antigen are more likely to be phagocytosed and killed

3. Opsonization

process where opsonins cover a bacterial cell enhancing phagocytosis
recognition and attachment

opsonins: molecules bind to pathogens and phagocytes, promote phagocytosis
antibody can act directly as opsonins

ingestion

phagocyte extends pseudopodia
particle becomes completely surrounded in phagocytic vacuole

killing

inside vacuole
lysosome-independent killing mechanism: no fusion of phagosome with lysosome

generation of oxygen radicals
production of nitric oxide

lysosome-dependent

normal circumstances
exposes contents of phagosome to lysosomal products (toxic/microbicidal)
generation of chlorine products
defensins
proteolytic enzymes (lysozyme)

degradation

excreted by phagocyte
degradation of microbial proteins can generate antigenic peptides presented on surface of macrophages
stimulate CD4 T

4. 3 pathways Activation of complement and cell lysis

classical

C1 bind to Ab-Ag complexes
C1 bind to Fc of Ab (complement fixation)
C1 subunits: C1q, C1r, C1s
binding subunit: C1q
once binding occur, C1r activated form C1r** (active)
C1r cleaves C1s
activation of C1s**
C1s** cleaves C4 into C4a and C4b
C4b attach to cell membrane
C4a diffuses away
C4b bind C2
when C2 is bound, cleaved by C1s** into C2a and C2b
C2b diffuses away
C2a remain bound to C4b
C4b.C2a form active enzyme complex: C4b.C2a**
C4b.C2a** is a C3 convertase
C3 bind to C4b.C2a**
cleaved into C3a and C3b
C3a diffuses away
C3b acts as opsonins or binds to C4b.C2a**
form C4b.C2a.C3b**, convertase of C5
cleaves C5 into C5a and C5b
C5a diffuses away
C5b binds to cell surface
C6~C9 involve in formation of membrane attack complex (MAC)
C5b is quite labile and has about 2 min to bind to C6 b4 it is inactivated
C5b.C6 complex binds C7 and C8
C5b.C6.C7.C8 complex form small pores in membrane, result in lysis of some microorg
most cells not lysed, require C9
C5b.C6.C7.C8 complex can add up to 16 C9 molecules
C9 assemble to form larger pore
lysis will occur due to osmotic imbalance

lectin

mannose binding protein (MBP) in serum binds to mannose residues on surface of pathogens
when MBP bound to pathogen
protease MASP binds to MBP
MBP-MASP complex cleaves C4 into C4a and C4b, C2 into C2a and C2b
once C4b is generated, it binds to cell surface and the rest is same like CP

alternative

C3 in serum is quite labile
spontaneous hydrolysis (low level)
forms C3a and C4b
some C3b binds to body cell
inactivated by surface membrane regulatory proteins
many microbes lack of regulatory proteins
C3b bound to microbial membrane is not activated (innate can distinguish self and non-self)
microbes opsonized
if C3b not activated, binds to factor B
cleaved by factor D
form Ba and Bb
Ba diffuses away
Bb remains bound to C3b
form active C3 convertase (C3b.Bb**)
C3b.Bb** can cleave more C3, generate more C3b
some C3b binds to C3b.Bb
form C3b.Bb.C3b, convertase of C5
C3b.Bb.C3b cleaves C5 into C5a and C5b
once C5a and C5b generated, formation of MAC

5. Ab-dependent cell-mediated cytotoxicity

mediated by neutrophils, NK, eosinophils, macrophages
not phagocytosis
Ab-Ag complex bound by FcR on NK
cross linking of FcR signals NK kill target cells
induce apoptosis
release lytic enzyme and TNF⍺

Chapter 7 Cell-mediated response

1. Killing mechanisms of CTL and 4 stages involves perforin and granzymes

CTL=CD8 T

granule exocytosis

recognition and binding of target cell

recognize antigen/class I MHC thro binding of its TcR

delivery of a lethal hit

granules in T cell move toward the site of attachment to the target cell
granules fuse with membrane of CTL and contents of granules released

death of the target cell

Perforin inserts into the target cell membrane and polymerize to form pores
Granzymes enter the target cell thro these pores, cleave proteins
results in activation of apoptosis

recycling of CTL

CTL detach from the target cell
kill other target cell bearing the antigen/class I MHC

Fas pathway

molecule expressed on many cell types
interact with Fas-ligand (Fas-L) in Tcs to activate apoptosis
binding of TcR of CD8 cytotoxic T cells to its specific antigen or class I MHC
cause expression of Fas-L
Fas on the target cell will be cross-linked by Fas-L on CTL
apoptosis will be triggered
not effective against all cells because not all cells express Fas

2. Compare between CTL and Th cells (CD4 and CD8)

CTL

kill certain cells (foreign cells, cancer cells, virus-infected cells)
carries CD8 cells
recognize antigens presented with MHC I molecules
antigens presented on surface of all nucleated cells

recognize foreign antigens, secrete cytokines that activate T and B cells
carries CD4 markers
recognize antigens presented with MHC II molecules
antigens presented by macrophages, dendritic cells (APC)

3. Delayed-type hypersensitivity (Type IV)

Aim

recruit monocytes to the site of infection
keep monocytes and tissue macrophages at the site of infection
activate the monocytes and macrophages to kill IC org

Cellular features

activation of CD4 T

pathogens shed antigens which can be picked up by dendritic cells (DC), leave tissue site, migrate via lymphatic vessels to lymph nodes
DC process antigen, express class II MHC molecule/antigen complex on surface
in lymph node, MHC II activates CD4 T
CD4 T proliferate and differentiate into Th1

migration of effector Th

Th leave lymph node, enter bloodstream, enter tissue
TNF⍺ and IL-2 made by macrophages and Th which stimulate local endothelial cells to express adhesion molecules

recruitment and retention of monocytes

stimulated by cytokines to differentiate into macrophages

activation of macrophages

Th secrete cytokines (IFN𝛾, TNF⍺ and IL-2)
activated macrophages up-regulate class II MHC expression on their cell surface
Th stimulated by recognizing antigen expressed by macrophages
secrete more cytokines for further activation (response amplified)

elimination of pathogens in DTH

Chapter 8 Hypersensitivity/allergy: an immune response results in exaggerated reactions harmful to the host/undesirable reactions

require pre-sensitized state of host

1. Allergens

inhalant: pollens, house dusts, feathers, pet hairs
ingestants: food proteins, drugs
drugs: as haptens, antisera, vaccines
injectants: injected drugs, diagnostic reagents, insect venom
contactants: drugs, paints, plants resins, preservative, metal

2. Type I (IgE mediated)

2~30 min
hay fever, asthma, food allergies, eczema
immediate/anaphylactic hypersensitivity
may cause range of symptoms from minor inconvenience to death
primary cellular component: mast cell or basophil
release of histamine (vasoactive mediators), vasodilation, main cause of typical allergic reactions, runny nose, watery eyes, itchy red skin
inhaled allergens, constricted airways, asthma
ingestants, cramp, vomiting, diarrhea
anaphylactic shock (bloodstream), airways constrict, tongue swell, difficult breathing, sudden dilation of blood vessels, loss of fluid, cause circulatory collapse

3. Type II (Antibody-mediated)

5~8 h
blood transfusion, erythroblastosis fetalis, autoimmune hemolytic anemia (AIHA)
cytotoxicity hypersensitivity
IgM or IgG
an antibody reacts with antigen on the cell surface
antigen may be part of cell membrane or circulating antigen or hapten that attaches to cell membrane
mismatch in blood transfusion, host defenses cause destruction of foreign blood

4. Type III (Immune-complex mediated)

2~8 h
arthritis, glomerulonephritis, SLE
results when allergens are distributed throughout the body
body produced antibodies, form insoluble antibody-antigen complexes
body unable to clear
a large inflammatory response develops
antigen initially soluble and not attached to organ involved
primary components are insoluble immune complexes and complement
lesion in damaged area contains primarily neutrophils and deposits of immune complexes and complement
farmer's lung (inhalation of mould growing on hay), mushroom grower's lung (inhaling spores produced by mushrooms)
microbial infection, syphilis malaria leprosy

5. Type IV (cell-mediated)

24~72 h
contact dermatitis, tubercular lesion, graft rejection
delayed hypersensitivity
appear much more slowly
caused by actions of a no of WBC
inflammatory responses caused by release of chemicals from T cells (lymphokines)
contact dermatitis, skin contact with poison ivy, heavy metals (mercury), cosmetics and deodorants
small substances evoke immune response
upon absorption thro skin, they bind to body proteins (foreign)

6. Skin prick test

used to measure allergic responses
The immunologist limits allergic reactions to local areas of the skin (arm or back), by pricking the skin with a small drop of allergen.
A 'weal' indicates an allergic response - this is verified by pricking samples of saline and histamine as controls (these should give negative and positive results respectively).
On discovering an allergy, the patient can then take steps to avoid the allergen or, in some cases, undergo desensitizing injections, which exposes the patient to increasing concentrations of allergen.

Chapter 9 Tolerance: a state of unresponsiveness specific for a given antigen. It is usually caused by exposure to a non-immunizing dose of antigen.

1. Mechanism of tolerance

https://www.slideshare.net/AllergyChula/immune-tolerance-231309953

Central tolerance

immature lymphocytes recognize self-antigens in generative lymphoid organs (thymus for T, bone marrow for B)
may lead to clonal deletion, receptor editing in B cells, development of regulatory T lymphocytes from CD4+ T cells

Peripheral tolerance

in mature lymphocytes recognize self-antigens in peripheral sites
may lead to clonal anergy, clonal deletion, suppression

Clonal deletion: physical elimination of cells from the receptor during their lifespan
Clonal anergy: downregulating the intrinsic mechanism of immune responses (lack of co-stimulatory molecules or insufficient signal for immune cell activation)
Suppression: inhibition of cellular activation by interaction with other cells

2. General properties and factors important in its induction

immature lymphocyte is more susceptible to tolerance induction than mature one
tolerance to foreign antigens is induced even in mature lymphocytes under special conditions
tolerance of T lymphocytes is a particularly effective for maintaining long-lived unresponsiveness to self-antigens

November 2019

SECTION A: OBJECTIVE QUESTIONS (20 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS

Figure 1

Residence for a variety of mature lymphoid cells

1. Statement in Figure 1 is referring to which organ?

(A) spleen*--lymph nodes

(B) kidney

(D) bone marrow

2. Which of the following is a component of adaptive immunity?

(A) lysozyme

(B) gut microbiota

(D) natural killer cells

3. During an inflammatory response, which vasoactive substances increase smooth muscle contraction?

(A) kinins--stimulate vasodilation and increased capillary permeability

(B) histamines--stimulate vasodilation and increased capillary permeability

(D) prostaglandins--stimulate vasodilation and increased capillary permeability, chemoattractant for neutrophils

4. The two shorter subunits of an antibody are called

(A) J chains

(B) L chains*--light chains

(D) M chains

5. Antigen binding site of an antibody is located in its

(A) epitope

(B) Fc region

(D) disulphate bridges

6. Naïve B cells express two forms of immunoglobulin (Ig) on their surface which are

(A) IgE and IgD

(B) IgA and IgG

(D) IgM and IgD*

7. Immunoglobulin A is protected from being degraded by mucosal proteolytic enzymes due to the presence of

(A) J chain

(B) opsonin

(D) secretory component*

8. The proliferation of CD4 helper T cells during the early stages of antibody production is driven by

(A) cytokines*--IL-2

(B) leucokines

(D) prostaglandins

9. The presence of secondary follicles with a germinal centre in a lymph node indicates

(A) an ongoing immune response*

(B) an invasion by metastasized cancer cells

(D) fungal colonization in the lymph node cortex

10. The total binding strength between antigen and antibodies is called

(A) avidity*

(B) affinity--the strength with which an individual binding site of an Ab binds to its epitope

(D) proximity

11. Cytotoxic T lymphocytes recognize antigen expression by antigen-presenting cells (APC) in the presence of

(A) complement C3

(B) Immunoglobulin G

(D) major histocompatibility complex class II--CD4 (helper T)

12. Parasite infestation in the human body may result in the activation of which immune mechanism?

(A) opsonization

(B) complement fixation

(D) antibody-dependent cell-mediated cytotoxicity*

13. Plasma factor B and factor D are involved in which complement pathway?

(A) lectin

(B) humoral

(D) alternative*

14. Granules exocytosis involving perforins and granzymes is an effector mechanism for

(A) macrophages

(B) helper T cells

(D) cytotoxic T cells*

15. Which of the following type of hypersensitivity reactions is cell-mediated?

(A) type I

(B) type II

(D) type IV*

16. Hypersensitivity reactions involving antibodies against cell surface or extracellular matrix antigens is classified as a hypersensitivity

(A) type I

(B) type II*

(D) type IV

17. Histamine released by reactive mast cells in allergic reactions is responsible for

(A) secretion of mucus

(B) the attraction of eosinophils from blood

(D) vasodilation and increased vascular permeability*

18. A systemic allergic reaction is also referred to as

(A) eczema

(B) prophylaxis

(D) hypervolemia

19. What is the general definition for autoimmunity?

(A) loss of tolerance to self-antigens*

(B) increase of tolerance to self-antigens

(D) increase in clonal deletion of mutant cells

20. Which of the following are functions of secondary lymphoid organs?

I. traps for antigen

II. producing cytokines and chemokines

III. residence for a variety of lymphoid cells

IV. the anatomical site where immune responses are initiated

(A) I, II and III

(B) I, II and IV

(D) II, III and IV

SECTION B: TRUE AND FALSE QUESTIONS (10 MARKS)

STATE WHETHER THE FOLLOWING STATEMENTS ARE TRUE (T) OR FALSE (F).

1. Lymphocytes and monocytes derived from a similar lineage of progenitor cells. F

2. Epithelial junctions of the skin and gut microbiota are classified into the second-line body defense. F

3. Eosinophils and basophils commonly carry out phagocytosis in an inflammatory response. F

4. Natural killer cells are capable of lysing virus-infected cells and tumor cells. T

5. One cytokine can act on different cells (pleiotropic). T

6. IgE antibodies involved in sensitizing mast cells in allergic reactions. T

7. IgM antibodies found in the blood and all body fluids. F--IgG; IgM in blood and lymph fluid

8. Both CD4 and CD8 T lymphocytes recognize antigens through the T-cell receptor (TcR). T

9. Delayed-type hypersensitivity is also known as type IV hypersensitivity. T

10. Clonal anergy is a mechanism of central immune tolerance.

SECTION C: SHORT ANSWER QUESTIONS (30 MARKS)

ANSWER ALL QUESTIONS

1. a. Define inflammation. (2 Marks)

Local accumulation of fluid, plasma proteins and WBC that is initiated by physical injury, infection, or a local immune response

b. Name TWO (2) types of phagocytic white blood cells (WBC) that involved in an inflammation. (2 Marks)

Neutrophils, macrophages

c. Describe SIX (6) major physiological events that occur during an inflammatory response. (6 Marks)

Vasoconstriction refers to the constriction of blood vessels leading to decreased blood flow to a part

Vasodilation refers to the increased volume of blood flow to the site

Decreased velocity of blood flow to the site, leukocytes are able to slow down and adhere to vascular endothelium

Increased expression of vascular endothelial adhesion molecule, leukocytes are able to attach to vascular endothelium

Increased vascular permeability, fluid enters tissues

Influx of phagocytic cells into tissues due to increased margination and extravasation

2. Explain the characteristics of adaptive immunity. (10 Marks)

Actions requires days to develop

Response is specific

Response is enhance on repeated exposure to pathogen

Specificity, recognize particular Ag, highly specific

Diversity, customized by genetic recombination, recognize epitopes and antigenic determinants, highly diverse

Memory, faster response to repeat infection

Self/non-self recognition

Systemic, not restricted to initial infection site

3. Describe the characteristics of IgM and IgG antibodies. (10 Marks)

IgM--largest Ab (pentamer), found in blood and lymph fluid, 5~13% of the circulating Ab, involved in primary immune response, responsible for neutralization antigen, control bloodstream infections, very effective in agglutination and precipitation

IgG--smallest, found in all body fluids, produced by B cells in response to foreign antigen, 80~85% total serum Ig, involved in secondary immune response, the only isotype that can pass through placenta, also present in colostrum, responsible for protection of newborn, circulates in the blood and exits the vessels into tissues, capable of binding complement which will result in cell lysis

SECTION D: ESSAY QUESTIONS (40 MARKS)

ANSWER ALL QUESTIONS

Question 1

Discuss in detail the activation of CD4 helper T cell during the earlier stages of antibody production. (20 Marks)

0~5 d

first and critical stage

stimulation of CD4 T cell to helper T

occurs at lymph nodes and spleen

3 stages

delivery of Ag to lymph nodes or spleen

tissue infected by microbes, dendritic cells take up Ag by phagocytosis, leave infectious site and migrate to lymph nodes

process Ag, results in expression of class II MHC on surfaces for recognition by CD4 T

spleen deal with blood pathogens

activation of Ag-specific CD4 T cells

CD4 T should be able to recognize and respond to as few molecules of Ag/class II MHC as possible to initiate response

involves interaction of FcR on CD4 T cell surface with class II MHC on APC, and the reaction of co-stimulus as well

proliferation of activated CD4 T cells and differentiation into helper T

after activation of APC

proliferation driven by cytokines IL-2

peaks 3~4 days after initial contact with Ag, results in 10,000~100,000 fold increase

differentiate into helper T

cells move to cortex area of lymph nodes and interact with B cells

Question 2

Discuss the three pathways of complement activation and cell lysis. (20 Marks)

April 2019

SECTION A: OBJECTIVE QUESTIONS (20 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS

1. A polymorphonuclear neutrophil (PMN) is

(A) a bone marrow stem cell

(B) closely similar to a mast cell

(D) contain non-cytoplasmic granules

2. Macrophages are derived from

(A) basophil

(B) neutrophil

(D) granulocytes

3. Immunological unresponsiveness to self-antigens is called

(A) immunogen

(B) immune response

(D) immunological tolerance*

4. Which of the following is a primary lymphoid organ?

(A) spleen

(B) thymus*--bone marrow

(D) Peyer’s patch

5. Opsonization is the process when

(A) a bacterium is coated with antibody*

(B) a complement causes inflammation to occur

(D) all the complement cascades is attached to a bacterium

6. Substances that are recognized as foreign and provoke the immune responses are called

(A) hapten

(B) inducers

(D) antibodies

7. Which of the following is specifically killed by a natural killer cell?

(A) fungi

(B) protozoan

(D) tumor cells and cells infected by microorganism*

8. Dendritic cells

(A) play an important role in the development of allergies and hypersensitivity

(B) are mainly important in the defense against protozoan and helminth parasites

(C) are capable of recognizing specific pathogen-associated molecular patterns and play an important role in non-specific response*

(D) contain granules with histamine and other pharmacologically active substances that contribute to the inflammatory response

9. Which of the following mechanism is involved in phagocytosis?

(A) complement fixation

(B) production of opsonin*

(D) lysosomal mediated hydrolysis

10. Class I and II MHC molecules

(A) consist of a complex of two protein chains*

(B) contain alpha-1 and alpha-2 domains that forms an antibody-binding pocket

(C) consist of a complex of two protein chains and contain alpha-1 and alpha-2 domains that forms an antibody-binding pocket

(D) neither consist of a complex of two protein chains nor contain alpha-1 and alpha-2 domains that forms an antibody-binding pocket

11. Protection against microorganisms inside the cells is provided by

(A) interferon

(B) mast cells

(D) complement

12. CD8 is a marker of

(A) T-cell

(B) B-cell

(D) cytotoxic T-cell*

13. Which of the following immunoglobulin is associated with hypersensitivity reaction?

(A) Ig A

(B) Ig E--1

(D) Ig G--2

14. A Fab fragment is

(A) bound to an antigen*

(B) lacking of light chain

(D) attached with a disulfide bond

15. Which of the following statements does NOT apply to IgG?

(A) It can opsonize bacteria

(B) It neutralizes bacterial toxins

(D) It appears early in primary immune response*

16. The basic immunoglobulin unit is composed of

(A) two different heavy and two identical light chains

(B) two identical heavy and two different light chains

(D) two identical heavy and two identical light chains*

17. Clonal selection occurs when antigen is encountered by

(A) T-cell*

(B) mast cell

(D) neutrophils

18. Vaccination is a

(A) naturally acquired active immunity

(B) naturally acquired passive immunity

(D) artificially acquired passive immunity

19. T-dependent antigens

(A) are generally carbohydrates

(B) activates B cells without the aid of other lymphocytes

(D) must be processed before a cellular immune response can be initiated*

20. The alternative complement pathway plays important role in

(A) first-line defense mechanism

(B) third-line defense mechanism

(D) second-line defense mechanism*--innate

Classical: innate, adaptive

SECTION B: SHORT ANSWER QUESTIONS (40 MARKS)

ANSWER ALL QUESTIONS

1. State FIVE (5) immunologic techniques for detecting or quantifying antibody and antigen. (5 Marks)

2. Identify the characteristic of T lymphocytes. (5 Marks)

originate in red bone marrow

differentiate in thymus (primary lymphoid organ)

primarily located in lymphatic tissues

make up 70~80% of circulating lymphocytes

provide cellular immune response

3. Define antibody affinity and avidity. (2 Marks)

affinity measures strength with which an individual binding site of an Ab binds to its epitope/binding between a single Ag determinant and an individual Ab combining site

avidity measures overall strength of binding between multivalent Ag and Ab

4. Outline the mechanism by which antigen presenting cells (APCs) process and present antigens. (10 Marks)

5. Distinguish between primary and secondary immune response. (10 Marks)

6. Describe major functions of complement. (8 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

ANSWER ALL QUESTIONS

Question 1

Describe in detail the functions of antibody in immune response. (20 Marks)

Question 2

Explain in detail the acquired immune system. (20 Marks)

February 2018

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTION

1. Nonspecific host defences that exist prior to exposure to an antigen is called

(A) innate immunity*

(B) acquired immunity

(D) inflammatory immunity

2. First line of defence includes

(A) mucus*

(B) T cells

(D) dendritic cells

3. Kupffer cells are macrophages found on

(A) lung

(B) liver*

(D) brain

4. Which of the following is the site of T cell maturation?

(A) spleen

(B) thymus*

(D) bone marrow

5. Primary lymphoid organs include

(A) thymus and spleen

(B) bone marrow and spleen

(D) bone marrow, spleen and lymph nodes

6. CD4 is found on which cells?

(A) B cells

(B) Neutrophils

(D) T cytotoxic cells

7. The first immunoglobin produced in an infection is

(A) IgA

(B) IgD

(D) IgM*

8. The five heavy chain isotypes of immunoglobins are

(A) G, I, T, H, E

(B) E, F, G, A, K

(D) G, M, D, E, A*

9. Immunoglobulins are produced by

(A) Dendritic cells

(B) B lymphocytes*

(D) Large granular lymphocytes

10. The immunoglobulin often found in secretions as a dimer is

(A) IgA*

(B) IgE

(D) IgM

11. Which of the following immune mechanism is responsible for protecting us from diseases of other species?

(A) active immunity*

(B) innate immunity

(D) adaptive immunity

12. The antigen binding site on an antibody is called

(A) epitope*

(B) antitope

(D) endotope

13. Light chains and heavy chains are joined by

(A) ionic bond

(B) covalent bond

(D) disulphide bond*

14. The ability of antigen to stimulate antibody production is called

(A) affinity

(B) activity

(D) antigenicity*

15. A molecule that reacts with specific antibody but is not immunogenic by itself is called

(A) hapten*

(B) carrier

(D) immunogen--Any molecule that induces or elicits an immune response are

16. Activation of B cell receptor by the binding of an epitope result in the formation of

(A) plasma cells and T cytotoxic cells

(B) memory cells and T cytotoxic cells

(D) plasma cells for antibody production and memory cells for secondary response*

17. Vaginal bacterial symbionts like Lactobacilli prevents pathogen by

(A) secreting toxins

(B) activate cytokines

(D) producing lactic acid thereby reducing pH*

18. Tissue damage caused by wound or invading pathogenic organisms induces a complex sequence of events collectively knowns as

(A) thermogens

(B) opsonisation

(D) inflammation*

19. Antiviral glycoproteins released by living cells in response to viral attack and induce a viral resistant state to neighbouring cells is called as

(A) interferons*

(B) phagocytes

(D) complement system

20. B cell has receptor on its surface which is

(A) dimeric IgM

(B) B cell receptor*

(D) monomeric IgM

21. The process of introduction of weakened pathogen into human body is called

(A) attenuation

(B) vaccination*

(D) virulence reduction

22. Classical pathway of complement system is activated by

(A) antigen

(B) antigenic peptides

(D) antibody-antigen complexes*

23. Which of the following is the central molecule in complement pathway

(A) C1

(B) C2

(D) C3b*--C5b

24. Allergies to sea foods, eggs are an example of

(A) Type I hypersensitivity*

(B) Type II hypersensitivity

(D) Type IV hypersensitivity

25. Allergy to penicillin is an example of

(A) Type I hypersensitivity

(B) Type II hypersensitivity

(D) Type IV hypersensitivity

26. Type IV hypersensitivity is also called as

(A) delayed hypersensitivity*

(B) cytotoxic hypersensitivity

(D) immune complex hypersensitivity

27. The most common class of antibody involved in type II hypersensitivity is

(A) IgD

(B) IgE

(D) IgM

28. The transfer of individuals own tissue to another part of the body is called

(A) allograft

(B) autograft*--autotransplantation

(D) syngeneic graft

29. The major molecules responsible for rejection of transplant is

(A) B cells

(B) T cells

(D) MHC molecules*

30. All the given vaccines are attenuated or inactivated whole pathogen, EXCEPT

(A) HIV*

(B) sabin

(D) hepatitis A

SECTION B: SHORT ANSWER QUESTIONS (30 MARKS)

ANSWER ALL QUESTIONS

1. Define (10 Marks)

i. Hapten

smaller substance with reactivity but lacks immunogenicity

ii. Epitope

small part of a large Ag which acts as trigger for immune response

iii. Antigen

iv. Affinity

v. Immunogen

2. a. State TWO (2) characteristic of innate immune system. (2 Marks)

non specific

no memory

limited diversity

b. Point out FOUR (4) example of instrinsic epithelial barriers to infection. (8 Marks)

3. a. Name THREE (3) types of antigen presenting cells (APC) (3 Marks)

dendritic cells, macrophages, B cells

b. Give THREE (3) roles of B cells. (3 Marks)

mainly involved in Ab production

develop into plasma cells, produce Ab

present Ag to T cells

develop into plasma or memory cells in bone marrow

recognition of Ag through Ab

c. Recall FOUR (4) roles of T cells. (4 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

ANSWER TWO (2) QUESTIONS ONLY

Question 1

With the aid of diagram, explain five types of immunoglobulin classes. (20 Marks)

IgG monomer (80~85%)

can cross placenta
smallest Ab
found in all body fluids, colostrum
responsible for protection of newborn
secondary immune response

IgM pentamer (5~13%)

first Ab secreted by B
largest Ab
found in blood, lymph fluid
responsible for neutralize Ag and controls bloodstream infection
primary immune response
can bind to B cell surface

IgA dimer (10~13%)

produced in mucous lining, found in mucous secretions
prevents colonization by pathogens
2 subclasses: IgA1, IgA2
present in large quantities in breast milk

IgE monomer

found in mammals
defends against parasitic invasion
responsible for allergic reactions
mediates release of histamine and heparin

IgD monomer (1%)

produced in secreted form in small amount
unknown functions
can bind to B cell surface

Question 2

Explain the mechanism of antigen processing and presentation in major histocompatibility complex (MHC) class I and MHC class II. (20 Marks)

endogenous Ag are produced within the cell and are processed and presented by MHC class I

proteosomes have proteolytic activity and are able to degrade protein into peptide fragments

TAP transporter transport peptide fragments from cytoplasm to RER

presence of antigenic peptide is expressed on all cells surfaces of nucleated cells, presented to CD8 T cells

exogenous Ag derive from outside the cell and are processed and presented by MHC class II

extracellular proteins are endocytosed and degraded in lysosomes

fuses with lysosomes to form endolysosome

presence of antigenic peptide is expressed on APC, presented to CD4 T cells

Question 3

Compare and contrast type I hypersensitivity and type IV hypersensitivity. (20 Marks)

September 2017

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS.

1. First line defense immunity involves

(A) secretion of lactic acid*

(B) oxygen dependent phagocytosis

(D) lysis by molecule activation component (MAC)

2. Which of the following is the function of immune system?

(A) Mediates various hormonal pathways.

(B) Identify cell expressing foreign cell surface marker.

(D) Releasing specific immunoglobulin molecules during the first exposure to non-self cell.*

3. Which of the following cells are agranulocytes?

(A) basophils

(B) monocytes*

(D) neutrophils

4. Which immunoglobulin involves in degranulation of B cell?

(A) IgA

(B) IgD

(D) IgG

5. Which factor decreases immunogenicity of an antigen?

(A) low degradability rate*

(B) high mutation frequency

(D) great complexity in molecules structure

11. Which is the oxygen-independent phagocytes component?

(A) lactoferrin*--lysosomal hydrolase, lysozyme, defensins, acid pH

(B) nitric oxide--peroxynitrite (RNI), hydrogen peroxide, superoxide anion hydroxyl radical, hypochlorite

(D) peroxide phosphate

12. Which of the following events may occur as a result of an inflammatory response?

(A) intralysosomal digestion

(B) antigen-antibody neutralization

(D) membrane attack complex formation

13. Which is the effect from Tick bites?

(A) expression of interferon

(B) degradation by lysozyme

(D) proliferation of immunoglobulin E*

14. Which cytokine involves in differentiation of Th1 cells?

(A) interlukin-11

(B) interlukin-12*

(D) interlukin-17

15. Which cell surface marker is expressed by both plasma cell and Pro-B cells?

(A) CD 20*--40 memory, Th 78

(B) CD 24

(D) CD 38

16. Which is the major antigen presenting cell (APC) during Human Immunodeficiency Virus (HIV) infection?

(A) neutophils

(B) macrophages

(D) megakaryocyte

17. Which is the diagnostic marker in parasite infections?

(A) eosinophil*

(B) neutrophil

(D) dendritic cell

18. Chemotaxis mechanism is a

(A) process where the pathogens are killed by phagocytic cells

(B) chemical that involved in regulating body temperature during fever

(D) process of a directed migration of phagocytes by gradient increase or decrease of substances*

19. The region where an immunoglobulin is being classified into specific group is

(A) J chains

(B) L chains

(D) M chains

20. Which of the following activity occurs the earliest during antibody production?

(A) differentiation of CD4+ T cells into T helper*

(B) processing of antigen to activate MHC class II

(D) secretion of interlukin-2 after activation of dendritic cell

stimulation of B cells by Ag and interaction with Th--2

21. What is C4b2a3b?

(A) C2 convertase

(B) C3 convertase

(D) C5 convertase*

22. What is the example of active natural adaptive immunity?

(A) injection of immunoglobulin G

(B) babies receiving mandatory vaccination

(D) secretion immunoglobulin M during infection of Staphylococcus aureus*

23. Memory cell is generated from

(A) proliferation of plasma cells*

(B) differentiation of naive T cells

(D) effector T cells which resting at G1 stage of cell cycle

24. Which of the following is NOT the event occured at germinal center during antibody production?

(A) class switching of IgM to IgG

(B) affinity maturation of antibody

(D) differentiation of B cells into plasma cells

25. What is the advantage of live vaccine?

(A) able to replicate in host cells

(B) effective for virulence viral infection

(D) activates both innate immunity for a longer duration compared to killed vaccination

26. Which of the following is/are the causes of IgE-mediated hypersensitivity reaction?

I. latex glove

II. nonsteroidal drug

III. incompatible cross matched blood--2

IV. Systemic Lupus Erythematosus--3

(A) II only

(B) I and II*

(D) III and IV

27. Failure in self-cell tolerance causes autoimmunity through

(A) mutation of MHC-related genes

(B) inhibition of B cells from proliferation

(D) ability to recognize surface marker of self and non-self cell*

28. What is the advantage of monoclonal antibody as compared to polyclonal antibody?

(A) highly sensitive--specificity

(B) continuous supply*

(D) excellent molecule for screening diagnosis

29. What is the effect of granulocytes immunodeficiency?

(A) autoimmune disease

(B) graft-versus-host-disease

(D) repetitive bacterial infection

30. Which of the following is the description of Direct Coombs test?

I. agglutination appearance indicates positive result

II. utilized precipitation method to show positive result

III. to detect red blood cells sensitized with Ig alloantibody, Ig autoantibody and complement protein

IV. detects antibody against red blood cells by incubated serum with known antigenicity red blood cell

(A) I and III

(B) I and IV

(D) II and IV

SECTION B : SHORT ANSWER QUESTIONS (30 MARKS)

Answer ALL questions

1. a. What is the importance of toll-like receptor? (4 Marks)

b. Name TWO (2) different names of macrophages in different tissues. (2 Marks)

alveolar macrophages (lung)

Kupffer cell (liver)

mesangial cell (kidney)

microglial cell (brain)

osteoclast (bone)

c. Draw and label MHC class II molecule. (4 Marks)

2. a. Describe the classical complementary pathway. (5 Marks)

b. Describe the antigen processing mechanism of exogenous antigen. (5 Marks)

phagocytosis of Ag

digestion of Ag into peptide fragments

synthesis of MHC molecules

fusion of vesicles

binding of peptide fragments to MHC molecules

insertion of Ag-MHC complex into plasma membrane

3. a. What is the advantage of using the following diagnosis method: (2 Marks)

i. serology technique

ii. immunoassay technique

b. List the application of serology and immunoassay method in diagnosis. (4 Marks)

c. What are the examples of serology and immunoassay techniques? (4 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

Answer TWO (2) questions ONLY.

Question 1

Explain the mechanisms of cell-mediated immunity activation after exposure to endogenous organisms. (20 Marks)

Question 2

Explain in detail the various factors affecting the immunogenicity of an antigen when exposed to human cells. (20 Marks)

Question 3

Tolerance mechanism occurs to avoid unnecessary immunological reaction. Explain the mechanism of tolerance. (20 Marks)

January 2017

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS.

1. Which of the following describes second line defense immunity?

(A) delayed action

(B) involves enzymes

(D) involves CD8 molecules

2. Which of the following is the description of IgD antibodies?

(A) able to cross placenta

(B) mediate maturation of B cells*

(D) predominate in the passive immunity in newborn

3. Which of the following cells are granulocytes?

(A) basophils*

(B) CD4 T cells

(D) natural killer cells

4. Which of the following immunoglobulin is present on the surface of B cell?

(A) IgA

(B) IgD*--IgM

(D) IgG

5. What makes monoclonal antibody is an effective diagnostic tool?

(A) less mutated

(B) highly specific

(D) long term action

6. What is the terminology of ‘genetically different individual’?

(A) isogenic

(B) allogenic

(D) heterogenic

7. Which of the following describes Fab fragment?

(A) lacks of light chain

(B) bounds to an antigen*

(D) attached with a disulfide bond

https://www.studocu.com/en-gb/document/aston-university/bsc-biomedical-science/by2im1-mcq-4-samplepractice-exam-2015-questions-and-answers/1488424

8. Which of the following is the site of T cell maturation?

(A) spleen

(B) thymus*

(D) bone marrow

9. Which of the following falls into third line body defense mechanism?

(A) fever

(B) phagolysozyme

(D) cell-mediated cytotoxic response*

10. B and T lymphocytes present in blood with a ratio of approximately

(A) 1:1

(B) 1:3

(D) 1:7

11. Which of the following effect is caused by the Schistosoma japonicum infection?

(A) expression of interferon

(B) degradation of lysozyme

(D) proliferation of immunoglobulin M

12. Which infection is protected by the recombinant vaccine?

(A) rotavirus

(B) polio virus

(D) influenza virus

13. Which of the following response is the indication of the presence of secondary follicles with germinal centers within lymph nodes

(A) an ongoing immune response*

(B) clearance of pathogens from body

(D) bone marrow is producing new immune cells

14. How do T cells are kept tolerant to avoid autoreactivity?

(A) elimination of T cyctotoxic cells

(B) supression of B cells proliferation

(D) functional inactivation of antigen-presenting cells

15. Which can be colonised by HIV?

(A) neutophils

(B) macrophages

(D) megakaryocyte

16. Which of the following immune cells involves mainly in parasite infections?

(A) eosinophils*

(B) neutrophils

(D) dendritic cells

17. What is the BEST definition of Chemotaxis?

(A) process where the pathogens are killed by natural killer cells

(B) product of cellular digestion that can associate with class I-MHC

(D) process of a directed migration of phagocytes to the inflammatory site*

18. The two longer subunits of an antibody is called

(A) J chains

(B) L chains

(D) M chains

19. Which of the following factor regulates or helps B cells differentiation?

(A) CD4 T cell

(B) CD8 T cell

(D) dendritic cell

20. What happen in the final stage of antibody production?

(A) differentiation of CD4 T cells into T helper

(B) differentiation of dendritic cells into macrophage

(D) differentiation of B cells into plasma or memory B cell*

21. Which complement pathway involves plasma factor B and factor D?

(A) lectin

(B) humoral

(D) alternative

22. What is the MOST commonly used protein subunit vaccine?

(A) tetanus toxoid

(B) rotavirus DNA

(D) hepatitis B surface antigen

23. Which infection is protected by the recombinant vaccine?

(A) rotavirus

(B) polio virus

(D) influenza virus

24. Which of the following characteristic of the antigen that can cause an immune response?

(A) degree of foreignness

(B) structurally unstable molecules

(D) composition of biochemical structure

25. What is the disadvantage of killed or inactivated vaccine?

(A) too expensive

(B) poor antibody responses

(D) does not stimulate cell-mediated immunity

26. Which of the following is/are the types of T lymphocytes?

I. CD4

II. CD8

III. CD16

IV. CD32

(A) II only

(B) I and II*

(D) III and IV

27. T cells will recognize and bind to its target antigens in the presence of

(A) Fab binding region

(B) Fc surface receptor

(D) minor histocompatibility complex

28. Which of the following is the mechanism of antibody response which preventing virus from invading the host cells?

(A) phagocytosis

(B) agglutination

(D) complement activation

29. Which of the following immune reaction is the MOST damaging to the host cells?

(A) phagocytosis

(B) Fas-mediated cytotoxicity

(D) antibody-dependant cell-mediated cytotoxicity

30. Which of the following location apart from lymph nodes and spleen, the clumps of lymphoid tissue may also be found?

I. pancreas

II. adenoids

III. appendix

IV. hypothalamus

(A) I and II

(B) I and IV

(D) III and IV

SECTION B : SHORT ANSWER QUESTIONS (30 MARKS)

Answer ALL questions

1. a. Define opsonization and immunogenic. (2 Marks)

b. Name TWO (2) oxygen dependent phagocytic mechanism. (2 Marks)

hydrogen peroxide, superoxide anion hydroxyl radical, hypochlorite

Reactive Nitrogen Intermediates; nitric oxide, peroxynitrite

c. Describe SIX (6) major physiological events that occur during an inflammatory response. (6 Marks)

2. Compare FIVE (5) differences between major histocompatibility complex (MHC) class I and II. (10 Marks)

MHC I--present on all nucleated cells, bind endogenous Ag, generated by proteosome, present Ag to CD8 T, have 8~10 amino acids

MHC II--present on APC, bind exogenous Ag, generated in lysosome, present Ag to CD4 T, have 13~18 amino acids

3. a. Define monoclonal and polyclonal antibodies. (2 Marks)

monoclonal--homogenous Ab population produced by single clone of plasma B cell, interact with particular epitope, expensive to produce

polyclonal--heterogenous Ab population produced by multiple clones of plasma B cells, interact with different epitope on same Ag, less expensive to produce

b. Draw and label the timeline of antibody response after first and second exposure towards antigenic molecules. (8 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

Answer TWO (2) questions ONLY.

Question 1

Discuss in detail of the mechanism of innate immunity. (20 Marks)

Question 2

Compare the differences between antibody-mediated versus cell-mediated response mechanism. (20 Marks)

Question 3

Explain in detail the new generation of different types of vaccines. (20 Marks)

August 2016

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS

1. Which of the following is the component of adaptive immunity?

(A) opsonization

(B) cytotoxic T lymphocytes*

(D) inflammation due to primary immune response

2. Immunoglobulins are produced by

(A) macrophages

(B) T lymphocytes

(D) large granular lymphocytes

3. The immunoglobulins often found in secretion as a dimer is

(A) IgA*

(B) IgE

(D) IgM

4. Which of the following pair is considered the primary lymphoid organs where the immunocompetent cells originate and mature?

(A) thymus and bone marrow*

(B) thyroid and Peyer’s patches

(D) spleen and mucosal-associated lymphoid tissue (MALT)

5. The antigen binding specificity of an antibody is due to

(A) the constant region of the light chain

(B) the variable region of the heavy chain

(D) the variable framework regions of the heavy and light chain*

6. All of the following are immunological function of complement EXCEPT

(A) chemotaxis

(B) opsonization

(D) anaphylatoxin formation

7. Which T cell expresses the CD8 marker and acts specifically to kill tumors or virally infected cells?

(A) T helper

(B) T inducer

(D) T suppressor

8. Which complement component is found in both the classical and alternative pathway?

(A) C1

(B) C3

(D) Factor D

9. Which major histocompatibility complex (MHC) class of antigen is necessary for antigen recognition by CD4?

(A) class I

(B) class II*

(D) none of the above

10. Vaccination is an example of

(A) naturally acquired active immunity--infection

(B) artificially acquired active immunity*

(D) artificially acquired passive immunity--antiserum

11. A complement component which is strongly chemotactic for neutrophils is

(A) C9

(B) C3

(D) C5a

12. Acute inflammation can be initiated by

(A) C3

(B) lysozyme

(D) influx of neutrophils*

13. A molecules that reacts with specific antibody but is not immunogenic by itself is called

(A) hapten*

(B) antigen

(D) protein carrier

14. Which immunoglobulin mediated immediate hypersensitivity and is involved in immune response to parasitic infections?

(A) IgA

(B) IgD

(D) IgG

15. Which of the following serologic tests is MISMATCHED with its used?

(A) Precipitation – indicate insoluble antigen

(B) Agglutination – determine particulate antigen

(D) Complement fixation – detect very small amounts of antibody

16. All of the following are functions of immunoglobulin EXCEPT

(A) neutralizing toxic substances

(B) facilitating phagocytosis through opsonization

(D) combining with complement to destroy cellular antigens

17. C reactive protein is a

(A) kinin

(B) cytokine

(D) acute phase protein

18. Which immunoglobulin appears in the highest titer in the secondary immune response?

(A) IgA

(B) IgE

(D) IgM

19. Which of the following is the site of T cell maturation?

(A) spleen

(B) thymus*

(D) bone marrow

20. A cytokine that activates cells to express MHC class II antigens and protects cells from virus replication is

(A) interleukin 2

(B) interferon beta

(D) interferon gamma

21. Which of the following is an antigen presenting cell (APC)?

(A) stem cell

(B) monocytes

(D) natural killer cell

22. Type IV hypersensitivity is often referred to as

(A) delayed response*

(B) allotypic response

(D) anaphylactic response

23. A Fab fragment is

(A) bound to an antigen*

(B) lacking of light chain

(D) attached with a disulfide bond

24. The basic immunoglobulin unit is composed of

(A) two identical heavy and two identical light chains*

(B) two different heavy and two identical light chains

(D) two different heavy and two different light chains

25. Which of the following is a reaction between soluble antibody and soluble antigen?

(A) precipitation

(B) agglutination

(D) Immunoflourescence

26. Complement factors C5b+C6+C7+C8 make up a complex that results in

(A) cytolysis

(B) opsonization

(D) enhanced phagocytosis

27. Newborn get their antibodies from mother milk. This is an example of

(A) naturally acquired active immunity

(B) naturally acquired passive immunity*

(D) artificially acquired passive immunity

28. Which of the following reaction is positive for complement fixation?

(A) hemolysis

(B) no hemolysis

(D) protein precipitation

29. Which of the following is TRUE about lymphocytes?

(A) It is present in lymph nodes permanently.

(B) It enters the tissue and remains for long period.

(D) It is recirculated between blood and lymphoid tissues.

30. Which of the following immunoglobulin has unknown function, is present on the surface of B lymphocytes?

(A) IgA

(B) IgD*

(D) IgG

SECTION B : SHORT ANSWER QUESTIONS (40 MARKS)

ANSWER ALL QUESTIONS

1. a. List THREE (3) major components of immune system and briefly describe their functions. (6 Marks)

b. Summarize the complement activation of mannan-binding lectin pathway. (4 Marks)

2. a. Distinguish between T-dependent and T-independent antigens. (4 Marks)

b. Briefly describe the role of antigen presenting cell (APC). (6 Marks)

3. a. Briefly explain the mechanism of hypersensitivity type II. (6 Marks)

b. Provide FOUR (4) immunology laboratory tests. (4 Marks)

SECTION C : ESSAY QUESTIONS (40 MARKS)

ANSWER TWO (2) QUESTIONS ONLY

Question 1

Describe the mechanism of antibodies production and their importance in immune system. (20 Marks)

Question 2

Explain the mechanisms of classical pathway complement activation. (20 Marks)

Question 3

Explain the cell-mediated immune response and humoral immune response. (20 Marks)

January 2016

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS

1. Which of the following cells is a phagocyte?

(A) basophils

(B) CD8 T cells

(D) natural killer cells

2. T lymphocytes are produced in bone marrow and mature in

(A) spleen

(B) thymus*

(D) Peyer’s patches

3. Natural killer cells derived from which cell lineage?

(A) monoblast

(B) myeloblast

(D) B cell precursor

4. Which of the following belongs to innate immunity?

(A) lysozyme*

(B) plasma B cells

(D) immunoglobulin M

5. A type of cytokines which typically released by virus-infected cells as a signaling protein is

(A) interferon

(B) interleukin*

(D) complement

6. Which of the following events may occur as a result of an inflammatory response?

(A) toxin neutralization

(B) granules exocytosis

(D) membrane attack complex

7. The cells responsible for the activation and priming of lymphocytes in lymph nodes is

(A) hairy cells

(B) plasma cells

(D) natural killer cells

8. Which of the following cytokine induces production of acute phase/C reactive proteins by the liver during an inflammation?

(A) interleukin-1 (IL-1)

(B) interleukin-6 (IL-6)

(D) tissue necrotizing factor alpha (TNF-α)

9. The two shorter subunits of an antibody is called

(A) J chains

(B) L chains*

(D) M chains

10. Antigen binding site of an antibody is located in its

(A) epitope*

(B) Fc region

(D) disulphate bridges

11. What is the type of antibody presents at high concentration in colostrum?

(A) Immunoglobulin E (IgE)

(B) Immunoglobulin A (IgA)*

(D) Immunoglobulin M (IgM)

12. Which of the following types of antibody has a secretory component attached to its structure?

(A) IgE

(B) IgA*

(D) IgM

13. Antibodies associated with B- lymphocytes cell surface expression are

(A) IgE and IgD

(B) IgA and IgG

(D) IgG and IgM

14. What type of reactions could be assessed by measuring plasma IgE levels?

(A) inflammation and phagocytosis

(B) T-cell-mediated reactions and tumor response

(D) type-I hypersensitivity and response to parasites

15. A specialized structure formed within lymphoid tissues following an encounter with antigen is known as

(A) white pulp

(B) germinal centre*

(D) medullary element

16. An important cell that regulates B cells differentiation for antibody production is

(A) CD4 T cell

(B) CD8 T cell

(D) dendritic cell

17. Major histocompatibility complex (MHC) class II could be expressed by which of these cells?

(A) neurons

(B) mesothelial cells

(D) squamous epithelial cells

18. In which part of the cell antigenic peptide fragments bind to the MHC molecules?

(A) nucleus

(B) Golgi complex

(D) cytoplasmic membrane

19. T lymphocytes binds to peptide and MHC complexes through

(A) epitope

(B) perforin

(D) T cell receptor

20. Which of the following is a potential effector cell in antibody-dependent cell mediated cytotoxicity?

(A) eosinophils

(B) neutrophils

(D) dendritic cells

21. Which complement pathway involves the interaction of plasma mannose binding protein (MBP) with mannose residue on the surface of pathogens?

(A) lectin

(B) humoral

(D) alternative

22. Granules exocytosis involving perforins and granzymes is an effector mechanism for

(A) macrophages

(B) helper T cells

(D) cytotoxic T cells

23. Which effector response carries the greatest potential damage to the host’s own tissues?

(A) Fas-mediated cytotoxicity

(B) opsonic-related phagocytosis

(D) activation of complement proteins

24. Which of the following vaccine types is able to stimulate both humoral and cell-mediated immunity?

(A) toxoid

(B) inactivated

(D) live attenuated

25. A vaccine booster dose will result in an increased plasma level of

(A) IgE

(B) IgA

(D) IgM

26. The only type of live vaccine had been used to provide immunization against

(A) poliovirus

(B) smallpox virus

(D) measles-mumps-rubella virus

27. Breakdown of immunological self-tolerance will result in

(A) splenomegaly

(B) autoimmunity

(D) immunodeficiency

28. Hypersensitivity reactions involving antibodies against cell surface or extracellular matrix antigens is classified as hypersensitivity

(A) type I

(B) type II

(D) type IV

29. Apart from lymph nodes and spleen, clumps of lymphoid tissue may also be found in

I. pancreas

II. adenoids

III. appendix

IV. hypothalamus

(A) I and II

(B) I and IV

(D) III and IV

30. Which of the following are functions of secondary lymphoid organs?

I. traps for antigen

II. producing cytokines and chemokines

III. residence for a variety of lymphoid cells

IV. anatomical site where immune responses are initiated

(A) I, II and III

(B) I, II and IV

(D) II, III and IV

SECTION B: SHORT ANSWER QUESTIONS (30 MARKS)

ANSWER ALL QUESTIONS

1. a. Define inflammation. (2 Marks)

b. Name TWO (2) cellular sources of pro-inflammatory cytokines. (1 Marks)

macrophages, infected cells and injured cells

c. Describe SIX (6) major physiological events that occur during an inflammatory response. (6 Marks)

2. a. Briefly explain THREE (3) main characteristics of an adaptive immunity. (3 Marks)

b. Provide examples of active and passive acquired immunity. (8 Marks)

3. a. Define delayed type hypersensitivity (DTH). (2 Marks)

b. Describe the aims of the DTH. (3 Marks)

c. Outline FIVE (5) cellular features of the DTH reaction. (5 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

ANSWER TWO (2) QUESTIONS ONLY

Question 1

Discuss in detail the stages of antibody production in lymphoid organs. (20 Marks)

Question 2

Discuss on the types of antibody mediated responses. (20 Marks)

Question 3

Discuss on immunological tolerance. Include the general properties of tolerance and factors important in its induction to support your answer. (20 Marks)

August 2015

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS

1. Which of the following cells are granulocytes?

(A) basophils*

(B) CD4 T cells

(D) natural killer cells

2. Which of the following falls into third line body defense mechanism?

(A) lysozyme

(B) inflammation

(D) delayed type hypersensitivity

3. Peptidoglycan in Gram positive bacteria is degradable by

(A) lysozyme

(B) histamine

(D) complement

4. Extravascular monocytes are called

(A) leukocytes

(B) macrophages*

(D) natural killer cells

5. B and T lymphocytes present in blood with a ratio of approximately

(A) 1:1

(B) 1:3

(D) 1:7

6. This type of cell is highly specialized in the activation and priming of lymphocytes in lymph nodes:

(A) hairy cell

(B) plasma cell

(D) natural killer cell

7. Which of the following is NOT a function of secondary lymphoid organs?

(A) traps for antigen

(B) producing cytokines and chemokines*

(D) anatomical site where immune responses are initiated

8. The presence of secondary follicles with germinal centers within lymph nodes indicates

(A) an ongoing immune response*

(B) an excessive accumulation of RBCs

(D) the bone marrow is producing new immune cells

9. Which of the following immune cells involves mainly in parasite infections?

(A) eosinophils*

(B) neutrophils

(D) dendritic cells

10. Breast milk, sputum, and gastric juice consist of which antibody type?

(A) IgA*

(B) IgD

(D) IgM

11. Chemotaxis is defined as a

(A) process where the pathogens killed by natural killer cells

(B) product of cellular digestion that can associate with class I-MHC

(D) process of a directed migration of phagocytes to the inflammatory site*

12. These are the categories of intrinsic epithelial barriers to infection EXCEPT

(A) microbial (normal flora)

(B) chemical (fatty acid, lysozyme)

(D) mechanical (tight junction, movement of mucus by cilia)

13. The two longer subunits of an antibody is called

(A) J chains

(B) L chains

(D) M chains

14. Antibodies bind to a part of antigens called

(A) MHC

(B) epitope*

(D) membrane

15. These antibodies are associated with B lymphocyte cell surface expression:

(A) IgE and IgD

(B) IgA and IgG

(D) IgG and IgM

16. Which of the following antibodies can pass through the mother placenta to the fetus?

(A) IgA

(B) IgG*

(D) IgM

17. An important cell that regulates or helps B cells differentiation is

(A) CD4 T cell

(B) CD8 T cell

(D) dendritic cell

18. The proliferation of CD4 T cells in antibody production is driven by

(A) leukokine

(B) cytokines*--IL-2

(D) prostaglandins

19. What is the final stage of antibody production?

(A) differentiation of CD4 T cells into T helper

(B) differentiation of dendritic cells into macrophage

(D) differentiation of B cells into plasma or memory B cell*

20. Major histocompatibility complex (MHC) class I

(A) is also called CD32.

(B) is associated with exogenous antigens type.--endo

(D) will stimulate recognition and binding of helper T cells upon expression.--CD8 T

21. Endogenous antigens are degraded into small peptide fragments by

(A) liposome

(B) proteasome*

(D) glucuosamine

22. T cells binds to peptide-MHC complexes through

(A) TcR--*

(B) epitope

(D) Fas-ligand

23. Effector mechanism of antibodies against Clostridium tetani or Corynebacterium diphtheriae is likely involves

(A) opsonisation

(B) agglutination

(D) antibody dependent cell-mediated cytotoxicity

24. Plasma factor B and factor D involve in which complement pathway?

(A) lectin

(B) humoral

(D) alternative

25. Effector mechanism of antibodies against parasitic worm infection is likely involves

(A) agglutination

(B) neutralization

(D) antibody dependent cell-mediated cytotoxicity

26. Delayed type hypersensitivity is also known as

(A) type I hypersensitivity

(B) type II hypersensitivity

(D) type IV hypersensitivity

27. Which of the following immune reactions is MOST damaging to the host cells?

(A) phagocytosis

(B) Fas-mediated cytotoxicity

(D) antibody dependent cell-mediated cytotoxicity

28. What is the MOST commonly used protein subunit vaccine?

(A) tetanus toxoid

(B) rotavirus DNA

(D) hepatitis B surface antigen

29. What is the disadvantage of killed or inactivated vaccine?

(A) too expensive

(B) poor antibody responses

(D) does not stimulate cell-mediated immunity

30. The two types of T lymphocytes are

I. CD4

II. CD8

III. CD16

IV. CD32

(A) II only

(B) I and II*

(D) III and IV

SECTION B: SHORT ANSWER QUESTIONS (30 MARKS)

ANSWER ALL QUESTIONS

1. a. Compare FIVE (5) differences between innate and adaptive immunity. (5 Marks)

b. Describe FIVE (5) functions of proinflammatory cytokines. (5 Marks)

phagocytosis

opsonization

activation of complement

initiate adaptive immune response

decreased viral and bacterial replication

increased Ag processing and specific immune response

2. a. State FOUR (4) stages of phagocytosis. (2 Marks)

b. Briefly explain each stage. (8 Marks)

3. a. Name TWO (2) killing mechanisms of cytotoxic T cell (CTL). (2 Marks)

b. Explain FOUR (4) stages of CTL killing mechanism that involves perforin and granzymes. (8 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

ANSWER TWO (2) QUESTIONS ONLY

Question 1

Discuss in detail the mechanisms of classical and alternative complement pathway. (20 Marks)

Question 2

Discuss the mechanisms of delayed-type hypersensitivity (DTH). (20 Marks)

Question 3

In your own words, discuss in detail the types of vaccine. (20 Marks)

January 2015

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

CHOOSE ONE BEST STATEMENT TO ANSWER THE QUESTIONS

1. Which of the following cells are found with lowest concentration in blood?

(A) basophils*

(B) neutrophils

(D) macrophages

2. Which of the following falls into third line body defense mechanism?

(A) lysozyme

(B) inflammation

(D) delayed type hypersensitivity*

3. This substance is able to degrade the peptidoglycan of Gram positive bacteria:

(A) lysozyme*

(B) histamine

(D) complement

4. Extravascular monocytes are called

(A) leukocytes

(B) macrophages*

(D) natural killer cells

5. B and T lymphocytes present in blood with a ratio of approximately

(A) 1:1

(B) 1:3

(D) 1:7

6. These cells are highly specialised in the activation and priming of lymphocytes:

(A) hairy cells

(B) plasma cells

(D) natural killer cells

7. Which of the following is NOT a function of secondary lymphoid organs?

(A) traps for antigen

(B) producing cytokines and chemokines*

(D) anatomical site where immune responses are initiated

8. The presence of secondary follicles with germinal centres within lymph nodes indicates

(A) an ongoing immune response*

(B) an excessive accumulation of RBCs

(D) the bone marrow is producing new immune cells

9. Spot the non-phagocytic immune cells below:

(A) eosinophils

(B) neutrophils

(D) dendritic cells*

10. Breast milk, sputum, and gastric juice consist of which antibody type?

(A) IgA*

(B) IgD

(D) IgM

11. Chemotaxis is defined as a

(A) process where the pathogens killed by natural killer cells

(B) product of cellular digestion that can associate with class I-MHC

(D) process of a directed migration of phagocytes to the inflammatory site*

12. These are the categories of intrinsic epithelial barriers to infection EXCEPT

(A) microbial (normal flora)

(B) chemical (fatty acid, lysozyme)

(D) mechanical (tight junction, movement of mucus by cilia)

13. The two shorter subunits of an antibody is called

(A) J chains

(B) L chains*

(D) M chains

14. Antibodies bind to a part of antigens called

(A) MHC

(B) epitope*

(D) membrane

15. The total binding strength between antigens and antibodies is called

(A) avidity*

(B) affinity

(D) proximity

16. These antibodies are associated with B lymphocyte cell surface expression:

(A) IgE and IgD

(B) IgA and IgG

(D) IgG and IgM

17. Which of the following antibodies can pass through the mother placenta to the fetus?

(A) IgA

(B) IgG*

(D) IgM

18. T cells will recognize and bind to its target antigens in the presence of

(A) Fab binding region

(B) Fc surface receptor

(D) minor histocompatibility complex

19. Endogenous antigens are degraded into small peptide fragments by

(A) liposome

(B) proteasome*

(D) glucuosamine

20. An important cell that regulates or helps B cells differentiation is

(A) CD4 T cell

(B) CD8 T cell

(D) dendritic cell

21. The proliferation of CD4 T cells in antibody production is driven by

(A) leukokine

(B) cytokines*

(D) prostaglandins

22. What is the final stage of antibody production?

(A) differentiation of CD4 T cells into T helper

(B) differentiation of dendritic cells into macrophage

(D) differentiation of B cells into plasma or memory B cell*

23. Plasma factor B and factor D involve in which complement pathway?

(A) lectin

(B) humoral

(D) alternative

24. Which of the following näive T cells may transform into cytotoxic T cell?

(A) CD2 T cell

(B) CD4 T cell

(D) CD8 T cell*

Figure 1

Bind to viruses and prevent them from entering the host cells

25. The mechanism of antibody response in Figure 1 refers to

(A) phagocytosis

(B) agglutination

(D) complement activation

26. Granule exocytosis will occur in the presence of

(A) CD4 T cells

(B) MHC class I

(D) complement C9

27. Which of the following immune reactions is MOST damaging to the host cells?

(A) phagocytosis

(B) Fas-mediated cytotoxicity

(D) antibody-dependant cell-mediated cytotoxicity

28. What is the MOST commonly used protein subunit vaccine?

(A) tetanus toxoid

(B) rotavirus DNA

(D) hepatitis B surface antigen

29. These are properties that ideal vaccines should have EXCEPT

(A) safety

(B) stability

(D) ease of administration

30. What is the disadvantage of killed or inactivated vaccine?

(A) too expensive

(B) poor antibody responses

(D) does not stimulate cell-mediated immunity

SECTION B: SHORT ANSWER QUESTIONS (30 MARKS)

ANSWER ALL QUESTIONS

1. a. Compare FIVE (5) differences between natural and acquired immunity. (5 Marks)

b. Describe FIVE (5) functions of proinflammatory cytokines. (5 Marks)

2. a. Define germinal centre. (2 Marks)

a specialized structure formed within lymphoid tissue following an encounter with Ag

b. Explain the way B cells are stimulated by antigen and their interaction with helper T cells in lymph nodes during antibody production process. (8 Marks)

Antigen bind to naive Bcr

Ag degradation in B cells

B cells as APC

MHC II bound antigenic peptide binds to Tcr

Tcr activate B cells by secreting chemokines

differentiation into plasma or memory cells

some differentiate into plasma cells secreting IgM

some undergo class switch to IgG (IgG secreting plasma cells)

after 4~7 days, some of the B and Th migrate to primary follicles to form germinal centre

3. a. Describe FIVE (5) properties of ideal vaccines. (5 Marks)

b. Explain briefly on attenuated vaccine. (5 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

ANSWER TWO (2) QUESTIONS ONLY

Question 1

Explain the characteristics of each antibody type presents in human body with diagrams. (20 Marks)

Question 2

Discuss in detail the mechanisms of classical and alternative complement pathway. (20 Marks)

Question 3

Discuss the mechanisms of delayed-type hypersensitivity (DTH). (20 Marks)

January 2014

SECTION A – OBJECTIVE QUESTIONS (30 MARKS)

Choose ONE best statement to answer the questions.

1. A polymorphonuclear neutrophil (PMN) is

(A) a bone marrow stem cell

(B) closely similar to a mast cell

(D) contain microbicidal due to its cytoplasmic granules*

2. Which of the following is a primary lymphoid organ?

(A) spleen

(B) thymus*--bone marrow

(D) Peyer’s patch

3. Which cell type produces antibodies?

(A) mast cell

(B) plasma cell*

(D) natural killer cell

4. Macrophages are derived from

(A) basophil

(B) neutrophil

(D) granulocytes

5. Substances that are recognized as foreign and provoke the immune responses are called

(A) inducers

(B) antigens*

(D) infective agents

6. Which of the following is specifically killed by a natural killer cell?

(A) fungi

(B) protozoa

(D) tumor cells and cells infected by microorganism*

7. Dendritic cells

(A) are mainly important in the defense against protozoan and helminth parasites

(B) play an important role in the development of allergies and hypersensitivity

(C) contain granules with histamine and other pharmacologically active substances that contribute to the inflammatory response.

(D) are capable of recognizing specific pathogen-associated molecular patterns and play an important role in non-specific resistance.*

8. Which of the following mechanism is involved in phagocytosis?

(A) complement fixation

(B) production of bacteriocins

(D) lysosomal mediated hydrolysis

9. Which of the following is an antigen presenting cell (APC)?

(A) stem cell

(B) monocyte

(D) natural killer cell

10. Several of the complement components are

(A) enzymes*

(B) cytokines

(D) glycolipids

https://sdbidoon.com/document/b-pharma-3rd-year-biotechnology-13.04%202020.pdf

11. Class I and II MHC molecules

(A) consist of a complex of two protein chains

(B) contain alpha-1 and alpha-2 domains that forms an antibody-binding pocket

(C) consist of a complex of two protein chains and contain alpha-1 and alpha-2 domains that forms an antibody-binding pocket

(D) neither consist of a complex of two protein chains nor contain alpha-1 and alpha-2 domains that forms an antibody-binding pocket

12. Which of the following is TRUE about lymphocytes?

(A) It is present in lymph nodes permanently.

(B) It enters the tissue and remains for long period.

(D) It is recirculated between blood and lymphoid tissues.

13. CD8 is a marker of

(A) B-cells

(B) T-cells

(D) cytotoxic T-cells*

14. Protection against microorganisms inside the cells is provided by

(A) T-cell

(B) antibody

(D) complement

15. T-cell surface receptors for recognize

(A) antigens*

(B) cytokines

(D) major histocompatibility cells (MHC)

16. Immunological unresponsiveness to self antigens is called

(A) memory

(B) tolerance*

(D) immunogen

17. Which of the following immunoglobulin is associated with hypersensitivity reaction?

(A) Ig A

(B) Ig D

(D) Ig G

18. Type IV hypersensitivity is often referred to as

(A) delayed response*

(B) allotypic response

(D) anaphylactic response

19. A Fab fragment is

(A) bound to an antigen*

(B) lacking of light chain

(D) attached with a disulfide bond

20. Which of the following statements does NOT apply to IgG?

(A) It can opsonize bacteria

(B) It neutralizes bacterial toxins

(D) It appears early in primary immune response*

21. The T cell receptor is comprised of

(A) complement C3

(B) delta protein chain

(D) alpha and beta protein chain*

22. The basic immunoglobulin unit is composed of

(A) two different heavy and two identical light chains

(B) two identical heavy and two different light chains

(D) two identical heavy and two identical light chains

23. Opsonization is the process when

(A) a bacterium is coated with antibody*

(B) a complement causes inflammation to occur

(D) all the complement cascades is attached to a bacterium

24. Clonal selection occurs when antigen is encountered by

(A) T-cell*

(B) mast cell

(D) neutrophils

25. Pyrogens are molecules that induce

(A) pain

(B) fever*

(D) inflammation

26. The alternative complement pathway plays important role in

(A) innate immunity

(B) specific immunity

(D) innate and adaptive immunities

27. Which of the following is a reaction between soluble antibody and soluble antigen?

(A) precipitation*

(B) agglutination

(D) immunoflourescence

28. Which of the following is NOT an example of autoimmune disease?

(A) multiple sclerosis

(B) rheumatoid fever*

(D) Parkinson’s disease

29. T-dependent antigens

(A) are generally carbohydrates

(B) activates B cells without the aid of other lymphocytes

(D) must be processed before a cellular immune response can be initiated

30. Vaccination is a

(A) naturally acquired active immunity

(B) naturally acquired passive immunity

(D) artificially acquired passive immunity

SECTION B – SHORT ANSWER QUESTIONS (30 MARKS)

Answer ALL questions.

1. a. List THREE (3) major components of immune system and briefly describe their functions . (6 Marks)

b. Briefly describe the physical and chemical barriers of host defenses. (4 Marks)

physical/mechanical--epithelial cells joined by tight junctions, block microbes, movement of mucus by cilia can remove pathogens from body, coughing eject pathogens from mouth

chemical--lysozyme from saliva, sweat , tears kill pathogens, stomach acid kills pathogens that enter GIT via water and food

microbiological--NF prevent colonization of pathogens, produce antibacterial substances

2. a. Distinguish between innate and adaptive immune responses. (6 Marks)

b. Identify FOUR (4) immunology laboratory tests. (4 Marks)

3. Define the following terms :

a. hapten

b. epitope

c. cytokine

d. vaccination

e. hypersensitivity

(10 Marks)

SECTION C – ESSAY QUESTIONS (40 MARKS)

Answer TWO (2) questions only.

Question 1

Describe the production of antibodies and their importances in the immune system. (20 Marks)

Question 2

Explain the mechanisms of antigen recognition in immune system. (20 Marks)

Question 3

Explain the cell-mediated immune response and humoral immune response. (20 Marks)

August 2013

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

Choose ONE best statement to answer the questions.

1. Which of the following cells constitute highest concentration in blood?

(A) basophils

(B) neutrophils*

(D) macrophages

2. Innate and adaptive immunity are similar respectively with

(A) simple and complex.

(B) natural and acquired.*

(D) neutral and non-neutral.

3. Which of the following is able to degrade peptidoglycan of gram positive bacteria?

(A) interferon

(B) histamine

(D) complement

4. Monocytes that have entered the extravascular pool and become resident in the tissues are known as

(A) leucocyte.

(B) macrophage.*

(D) natural killer cell.

5. The ratio of B- and T-lymphocytes in a blood is approximately

(A) 1:1.

(B) 1:3.

(D) 1:7.

6. Which of the following is NOT a major function of secondary lymphoid organs?

(A) traps for antigen

(B) origin of numerous types of cytokines*

(D) anatomical site in which immune responses are initiated

7. Which of the following cells is highly specialised in the activation and priming of lymphocytes?

(A) hairy cell

(B) plasma cell

(D) natural killer cell

8. The presence of secondary follicles with germinal centers in a lymph node indicates

(A) an ongoing immune response.*

(B) an excessive accumulation of RBCs.

(D) the bone marrow is producing new immune cells.

9. Which of the following is NOT a specialized macrophage in human body?

(A) osteoclast in bone

(B) Kupffer cell in liver

(D) reticulocyte in lymph node*

10. Which of the following are components of adaptive immunity only?

(A) proinflammatory cytokines

(B) B cells, MHC and dendritic cells*

(D) intact skin, epithelial layers, cough and fever

11. Breast milk, sputum, and gastric juice may consist of which antibody type?

(A) IgA*

(B) IgD

(D) IgM

12. Chemotaxis is defined as a

(A) process where the pathogens killed by natural killer cells.

(B) product of cellular digestion that can associate with class I-MHC.

(D) process of a directed migration of phagocytes to the inflammatory site.*

13. These are the categories of intrinsic epithelial barriers to infection, EXCEPT

(A) microbial (normal flora)

(B) chemical (fatty acid, lysozyme)

(D) mechanical (tight junction, movement of mucus by cilia)

14. The two shorter subunits of an antibody is called

(A) J chains

(B) L chains*

(D) M chains

15. Antibodies bind to a part of antigens called

(A) MHC

(B) epitope*

(D) membrane

16. The types of antibody associated with B-lymphocyte cell surface expression are

(A) IgE and IgB

(B) IgA and IgG

(D) IgM and IgD*

17. Which of the following antibodies can pass through the mother placenta to the fetus?

(A) IgA

(B) IgG*

(D) IgM

18. The T cells are able to recognize antigen presented on the surface of infected cells in the presence of

(A) complement

(B) Fab binding region

(D) major histocompatibility complex*

19. Antigens within the cellular cytoplasm are degraded into peptide fragments by

(A) proteosomes*

(B) glucuosomes

(D) carboxylasms

20. An important cell that regulates or helps B cells differentiation is

(A) CD4 T cell

(B) CD8 T cell

(D) dendritic cell

21. Which of the following is NOT a stage in T helper (Th) activation and proliferation?

(A) activation of antigen-specific CD4 T cells

(B) delivery of antigen to lymph nodes or spleen

(D) proliferation of activated CD4 T cells and differentiation into Th

22. The proliferation of CD4 T cells in antibody production mechanism is driven by

(A) leucokine

(B) cytokines*

(D) prostaglandins

23. What is the final stage in B cell differentiation?

(A) differentiation of CD4 T cell into T helper

(B) differentiation of dendritic cell into macrophage

(D) differentiation of B cell into plasma or memory B cell*

24. Which of the following is a complement pathway that involves components called factor B and factor D?

(A) Lectin

(B) Humoral

(D) Alternative*

25. Which of the following naive T cells can transform into cytotoxic T cell?

(A) CD2 T cell

(B) CD4 T cell

(D) CD8 T cell*

Limit the spread of pathogens by retaining them in clumps

Figure 1

26. The process of immune response in Figure 1 refers to

(A) phagocytosis

(B) agglutination*

(D) complement activation

27. Which of the following immune responses associated with parasite infections?

(A) opsonisation

(B) complement activation

(D) antibody-dependent cell-mediated cytotoxicity

28. Granule exocytosis will occur in the presence of

(A) CD4 T cells

(B) MHC class I

(D) complement C9

29. The type of cell commonly involved in delayed-type hypersensitivity is

(A) Goblet cell

(B) dendritic cell

(D) natural killer cell

30. Which of the following immune reactions is most damaging to the host cells?

(A) Phagocytosis

(B) Neutralisation

(D) Membrane attack complex

SECTION B: SHORT ANSWER QUESTIONS (30 MARKS)

Answer ALL questions.

1. a) List FIVE (5) differences between innate and adaptive immunity. (5 Marks)

b) Describe FIVE (5) functions of proinflammatory cytokines. (5 Marks)

2. a) Write a short note on T lymphocytes. (5 Marks)

b) Name the secondary lymphoid organs in human. (1 Mark)

spleen, lymph nodes

c) List FOUR (4) events that occur in germinal centres during antibody production. (4 Marks)

Ab class switch

affinity maturation of Ab

differentiation of B cells into memory cells

differentiation of B cells into plasma cells

3. a) Define endogenous and exogenous antigens. (2 Marks)

endogenous Ag: compound generated within cell

exogenous Ag: foreign compound enter body from outside

b) Describe FIVE (5) functions of phagocytes. (5 Marks)

c) Explain briefly how the antigenic peptides get to the MHC molecules in the cell-mediated immunity. (3 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

Answer TWO (2) questions only.

Question 1

Discuss the characteristics of each antibody type presents in human body. (20 Marks)

Question 2

Discuss in detail the mechanisms of the classical complement pathway. (20 Marks)

Question 3

Discuss the mechanisms of CD8 T cell mediated cytotoxicity. (20 Marks)

January 2013

SECTION A: OBJECTIVE QUESTIONS (30 MARKS)

Choose ONE best statement to answer the questions.

1. Which of the following cells are found with highest concentration in blood?

(A) basophils

(B) neutrophils*

(D) macrophages

2. The terms innate and adaptive immune responses are respectively similar with

(A) simple and complex

(B) natural and acquired*

(D) neutral and non-neutral

3. Which of the following substances can degrade the peptidoglycan of gram positive bacteria?

(A) interferon

(B) histamine

(D) complement

4. When monocytes enter the extravascular pool and become resident in the tissues, they are called

(A) leucocyte

(B) macrophage*

(D) natural killer cell

5. B- and T-lymphocytes present in blood in a ratio of approximately

(A) 1:1

(B) 1:3

(D) 1:7

6. Which of the following cells is highly specialised in the activation and priming of lymphocytes?

(A) hairy cell

(B) plasma cell

(D) natural killer cell

7. The presence of secondary follicles with germinal centers within the lymph nodes indicates

(A) an ongoing immune response*

(B) an excessive accumulation of RBCs

(D) the bone marrow is producing new immune cells

8. The following cells are able to function as a phagocyte EXCEPT

(A) basophil*--exhibit phagocytic activity

(B) monocyte

(D) macrophage

9. Which of the following are the components of adaptive immunity only?

(A) proinflammatory cytokines

(B) B cells, MHC and dendritic cells*

(D) intact skin, epithelial layers, cough and fever

10. Breast milk, sputum, and gastric juice may consist of which antibody type?

(A) IgA*

(B) IgD

(D) IgM

11. Chemotaxis is defined as a

(A) process where the pathogens killed by natural killer cells.

(B) product of cellular digestion that can associate with class I-MHC.

(D) process of a directed migration of phagocytes to the inflammatory site.*

12. These are the categories of intrinsic epithelial barriers to infection EXCEPT

(A) microbial (normal flora)

(B) chemical (fatty acid, lysozyme)

(D) mechanical (tight junction, movement of mucus by cilia)

13. The two longer subunits of an antibody is called

(A) J chains

(B) L chains

(D) M chains

14. Antibodies bind to a part of antigens called

(A) MHC

(B) epitope*

(D) membrane

15. The total binding strength between antigens and antibodies is called

(A) avidity*

(B) affinity

(D) proximity

16. The types of antibody associated with B-lymphocyte cell surface expression are

(A) IgE and IgB

(B) IgA and IgG

(D) IgM and IgD*

17. Which of the following antibodies can pass through the mother placenta to the fetus?

(A) IgA

(B) IgG*

(D) IgM

18. The T cells are able to recognize antigen presented on the surface of infected cells in the presence of

(A) Fab binding region

(B) Fc surface receptor

(D) minor histocompatibility complex

19. Antigens within in the cellular cytoplasm are degraded into peptide fragments by

(A) liphosome

(B) proteosome*

(D) carboxylasm

20. An important cell that regulates or helps B cells differentiation is

(A) CD4 T cell

(B) CD8 T cell

(D) dendritic cell

21. Which of the following is NOT the stage in helper T cell (Th) activation and proliferation?

(A) Activation of antigen-specific CD4 T cells

(B) Delivery of antigen to lymph nodes or spleen

(D) Proliferation of activated CD4 T cells and differentiation into Th

22. The proliferation of CD4 T cells in antibody production mechanism is driven by

(A) leucokine

(B) cytokines*

(D) prostaglandins

23. What is the final stage in B cell differentiation?

(A) Differentiation of CD4 T cell into T helper

(B) Differentiation of dendritic cell into macrophage

(D) Differentiation of B cell into plasma or memory B cell*

24. Which of the following pathways of complement activation involves plasma factor B and factor D?

(A) lectin

(B) humoral

(D) alternative*

25. Which of the following naive T cells can transform into cytotoxic T cell?

(A) CD2 T cell

(B) CD4 T cell

(D) CD8 T cell*

Figure 1

Limit the spread of pathogens by retaining them in clumps

26. The process of immune response in Figure 1 refers to

(A) phagocytosis

(B) agglutination*

(D) complement activation

27. Which of the following immune responses is usually associated with parasites?

(A) Opsonisation

(B) Complement activation

(D) Antibody-dependent cell-mediated cytotoxicity

28. Granule exocytosis will occurs in the presence of

(A) CD4 T cells

(B) MHC class I*--CTL

(D) complement C9

29. The type of cell that commonly involved in delayed-type hypersensitivity is

(A) Goblet cell

(B) dendritic cell*

(D) natural killer cell

30. Which of the following immune reactions is most damaging to the host cells?

(A) phagocytosis

(B) neutralization

(D) membrane attack complex

SECTION B: SHORT ANSWER QUESTIONS (30 MARKS)

Answer ALL questions.

1. a. Name FIVE (5) examples of specialized macrophages and their location in our body. (5 Marks)

b. Name the primary and secondary lymphoid organs in human. (2 Marks)

primary--bone marrow, thymus

secondary--lymph nodes, spleen

c. List THREE (3) major functions of secondary lymphoid organs. (3 Marks)

residence for a variety of lymphoid cells

traps for Ag

anatomical site in which immune responses are initiated

2. a. List FIVE (5) differences between innate and adaptive immunity. (5 Marks)

b. Describe FIVE (5) functions of proinflammatory cytokines. (5 Marks)

3. a. Describe FIVE (5) functions of phagocytes. (5 Marks)

b. Briefly explain how endogenous antigens are presented on the cell surface by major histocompatibility complex (MHC) molecule. (5 Marks)

SECTION C: ESSAY QUESTIONS (40 MARKS)

Answer TWO (2) questions only.

Question 1

Discuss in detail the three stages of antibody production. (20 Marks)

Question 2

Discuss in detail the mechanisms of the classical complement pathway. (20 Marks)

Question 3

Discuss the mechanisms of CD8 T cell mediated cytotoxicity and the delayed type hypersensitivity. (20 Marks)

2/2009/2010

PART A – OBJECTIVE QUESTIONS (30MARKS)

Answer all questions in the OMR sheet provided.

1. Lymphocytes cell include the following EXCEPT

A. T cells

B. B cells

C. Macrophages*

D. Natural killer cells

2. Immunoglobulin are produced by

A. large granular lymphocytes.

B. B lymphocytes.*

C. T lymphocytes.

D. dendritic cells.

3. The most abundant leukocytes in the blood of healthy person are

A. lymphocytes.

B. eosinophils.

C. monocytes

D. neutrophils*

4. Which one of the following is a primary lymphoid organ?

A. Lymph nodes.

B. Liver.

C. Spleen.

D. Thymus.*

5. The major class of immunoglobulin found on the surface of the walls of the intestines and airways is

A. IgG.

B. IgM.

C. IgA.*

D. IgD.

https://quizlet.com/29975076/ch-16-adaptive-immunity-flash-cards/

6. Which cells express MHC class I molecules?

A. Red blood cells.

B. Antigen-presenting cells only.

C. Neutrophils only.

D. All nucleated cells.*--CD8 T

7. In which of following sites can B cells can be found?

A. Lymph nodes.

B. Spleen.

C. Intestinal wall.

D. All of the above*--+ red bone marrow

8. Cytotoxic T-cells

A. kill viruses directly.*

B. are usually have CD4.

C. restrict viral replication.

D. do not have surface receptor.

9. Clonal selection occurs when antigen is encountered by

A. eosinophils.

B. mast cells.

C. T-cells.*

D. neutrophils.

10. Specific antibodies are readily detectable in serum following primary contact with antigen after

A. 3-5 weeks.

B. 5-7 days.

C. 1 hour.

D. 10 minutes.

11. CD 8 is marker of

A. B cells.

B. activated macrophages.

C. helper T cells.

D. cytotoxic T cells.*

12. CD4 is found on which cells?

A. B cells.

B. Neutrophils.

C. T helper cells.*

D. T cytotoxic cells.

13. Which of the following classes of MHC protein are produced only by APCs?

A. Class I.

B. Class II.*

C. Class III.

D. Class IV

14. The first immunoglobulin class expressed on the surface of a newly produced B cell

A. IgG .

B. IgA.

C. IgD.

D. IgM*

15. The Fab region of immunoglobulin is responsible for

A. macrophage binding.

B. compliment fixation.

C. antigen binding.*

D. antigen presentation.

16. Immunological unresponsiveness to an antigen is called

A. tolerance.*

B. autoimmunity.

C. memory.

D. naiveity.

17. Which of the following is a reaction between antibody and particulate antigen?

A. Precipitation.*

B. Agglutination.

C. Flow cytometry.

D. Immunofluorescence.

18. T-dependent antigens

A. are usually carbohydrates.

B. include lipopolysaccharide.

C. are presented on MHC class II molecules.

D. are presented to Tc cells.

19. Secondary antibody response are better because

A. they provide defence against unrealted antigens.

B. the antibody can be made by both T cells and B cells.

C. they do not required T cell help.

D. they are more rapid and efficient in binding antigen.

20. Which cells produces Ig E?

A. Mast cells.

B. T lymphocytes.

C. Plasma cells.*

D. Basophils.

21. T cell lymphocytes

A. involved in humoral immunity.

B. cannot recognize free antigen.

C. mature in bone marrow.

D. Can produce antibody.

22. Hypersensitivity Type I associated with

A. cytotoxicity.

B. immune complex.

C. allergic reaction.

D. requires large amount of antigen.

23. Disease that associated with Hypersensitivity Type II.

A. Hemolytic anemia

B. Asthma

C. Thyrotoxicosis

D. Glomerulonephritis

24. In normal condition self antigen is

A. immunogenic.

B. tolerogenic.

C. antigenic.*

D. mutagenic.

25. Disease that associated with T lymphocytes deficiency is.

A. Agammaglobulinemia

B. Chronic granulomatus disease

C. DiGeorge syndrome

D. Complement deficiency

26. Regarding with AIDS, which of the following statement is TRUE?

A. Causes by rotavirus.

B. Virus infects CD4 T cells.

C. One of example of primary immunodeficiency.

D. Associated with genetic abnormalities.

27. Which of the statement below occur during inflammation process?

A. Decreases velocity of blood flow.*

B. Phagocytes flow slowly through vessels.--leukocytes

C. Vasoconstriction of blood vessels.*

D. Migration of erythrocytes into tissue.

28. Allergen

A. is normally parasite antigen.

B. can stimulate degranulation of mast cell.

C. is normally bind to Ig A.

D. can stimulate type III hypersensitivity.

29. The following are types of autoimmune reaction EXCEPT

A. cytotoxic

B. allergic

C. immune complex

D. cell mediated

30. The following are autoimmune diseases. EXCEPT

A. Grave disease

B. Di George Syndrome

C. Myasthemia gravis

D. Rheumatoid Arthritis

PART B: Short Answer Questions ( 40 Marks)

Answer ALL questions.

Question 1

a. List FOUR (4) changes occur during apoptosis. (4 marks)

b. State the series of steps in process of phagocytosis. (6 marks)

Question 2.

a. What is epitope? (2 marks)

b. Draw and label the complete structure of antibody. (8 marks)

Question 3

a. List SIX (6) protective outcome of antibody- antigen binding. (6 marks)

b. State the types of immunoglobulin associated with the statements below.

i. Immunoglobulin that can cross placenta. IgG

ii. Dimmer structure with J-chain. IgA

iii. 5% -13% of circulating antibodies in plasma. IgM

iv. Involved in development of antibody response. IgD

(4 marks)

Question 4

a. Define immunodeficiency. (2 marks)

b. List FOUR (4) types of primary immunodeficiency. (4 marks)

c. State the causes of secondary immunodeficiency. (4 marks)

PART C : Essay Questions (30 Marks)

Answer THREE (3) questions only.

Question 1

a. State the comparison between T dependent antigen and T independent antigen. (4 marks)

b. Briefly explain the comparison between cytotoxic T cells and helper T cells. (6 marks)

Question 2

a. Define humoral immunity? (2 marks)

synthesis of specific molecules by B cells (Ab) which are subsequently found in body fluids (blood and lymph fluid)

b. Briefly explain its process of humoral immunity production. (8 marks)

Question 3

a. What are the properties that an ideal vaccine should have? (2 marks)

b. Briefly explain FOUR (4) types of vaccines. (8 marks)

Question 4

Discuss the process of vascular dilation and smooth muscle contraction can in Type I Hypersensitivity? (10 marks)

1/2010/2011

SECTION 1

PART A – OBJECTIVE QUESTIONS (30 MARKS)

Answer all questions in the OMR objective sheet provided.

1. Lymphocytes include the following EXCEPT

A. T cells

B. B cells

C. Macrophages*

D. Natural killer cells

2. Immunoglobulin is produced by

A. large granular lymphocytes.

B. B lymphocytes.*

C. T lymphocytes.

D. dendritic cells.

3. The most abundant leukocytes in the blood of healthy persons are

A. lymphocytes.

B. eosinophils.

C. monocytes

D. neutrophils*

4. Which one of the following is a primary lymphoid organ?

A. Lymph nodes.

B. Liver.

C. Spleen.

D. Thymus.*

5. The major class of immunoglobulin found on the surface of the walls of the intestines and airways is

A. IgG.

B. IgM.

C. IgA.*

D. IgD.

6. Which cells express MHC class I molecules?

A. Red blood cells.

B. Antigen-presenting cells only.

C. Neutrophils only.

D. All nucleated cells.*

7. In which of following sites can B cells can be found?

A. Lymph nodes.

B. Spleen.

C. Intestinal wall.

D. All of the above*

8. Cytotoxic T-cells

A. kill viruses directly.*

B. usually have CD4.

C. restrict viral replication.

D. do not have surface receptor.

9. Clonal selection occurs when antigen is encountered by

A. eosinophils.

B. mast cells.

C. T-cells.*

D. neutrophils.

10. Specific antibodies are readily detectable in serum following primary contact with antigen after

A. 3-5 weeks.

B. 5-7 days.

C. 1 hour.

D. 10 minutes.

11. CD 8 is marker of

A. B cells.

B. activated macrophages.

C. helper T cells.

D. cytotoxic T cells.*

12. CD4 is found on which cells?

A. B cells.

B. Neutrophils.

C. T helper cells.*

D. T cytotoxic cells.

13. Which of the following classes of MHC protein are produced only by APCs?

A. Class I.

B. Class II.*

C. Class III.

D. Class IV

14. The first immunoglobulin class expressed on the surface of a newly produced B cell

A. IgG .

B. IgA.

C. IgD.

D. IgM*

15. The Fab region of immunoglobulin is responsible for

A. macrophage binding.

B. compliment fixation.

C. antigen binding.*

D. antigen presentation.

16. Immunological unresponsiveness to an antigen is called

A. tolerance.*

B. autoimmunity.

C. memory.

D. naiveity.

17. Which of the following is a reaction between antibody and particulate antigen?

A. Precipitation.*

B. Agglutination.

C. Flow cytometry.

D. Immunofluorescence.

18. T-dependent antigens

A. are usually carbohydrates.

B. include lipopolysaccharide.

C. are presented on MHC class II molecules.

D. are presented to Tc cells.

19. Secondary antibody response are better because

A. they provide defence against unrealted antigens.

B. the antibody can be made by both T cells and B cells.

C. they do not required T cell help.

D. they are more rapid and efficient in binding antigen.

20. Which cells produces Ig E?

A. Mast cells.

B. T lymphocytes.

C. Plasma cells.*

D. Basophils.

21. T cell lymphocytes

A. are involved in humoral immunity.--B cells

B. cannot recognize free antigen.*--recognize foreign Ag only

C. mature in bone marrow.--thymus

D. can produce antibody.--B cells

22. Hypersensitivity Type I is associated with

A. cytotoxicity.

B. immune complex.

C. allergic reaction.*

D. requires large amount of antigen.

23. Disease that are associated with Hypersensitivity Type II.

A. Hemolytic anemia

B. Asthma

C. Thyrotoxicosis

D. Glomerulonephritis

24. Under normal condition self antigen is

A. immunogenic.

B. tolerogenic.

C. antigenic.*

D. mutagenic.

25. A disease associated with T lymphocytes deficiency is

A. Agammaglobulinemia

B. Chronic granulomatus disease

C. DiGeorge syndrome

D. Complement deficiency

26. Which of the following statement is TRUE regarding with AIDS.

A. Causes by rotavirus.

B. Virus infects CD4 T cells.

C. One of example of primary immunodeficiency.

D. Associated with genetic abnormalities.

27. Which of the following occurs during the inflammation process?

A. Decreases velocity of blood flow.*

B. Phagocytes flow slowly through vessels.

C. Vasoconstriction of blood vessels.

D. Migration of erythrocytes into tissue.

28. Allergen

A. are normally parasite antigens.

B. can stimulate degranulation of mast cell.

C. normally bind to Ig A.

D. can stimulate type III hypersensitivity.

29. The following are types of autoimmune reaction EXCEPT

A. cytotoxic

B. allergic

C. immune complex

D. cell mediated

30. The following are autoimmune diseases. EXCEPT

A. Grave disease

B. Di George Syndrome

C. Myasthenia gravis

D. Rheumatoid Arthritis

SECTION 2

PART A: SHORT ANSWER QUESTIONS (20 MARKS)

Answer ALL questions.

Question 1

a. List FOUR (4) changes that occur during apoptosis. (4 Marks)

b. Write the series of steps during the process of phagocytosis. (6 Marks)

Question 2.

a. Define immunodeficiency. (2 Marks)

b. List FOUR (4) types of primary immunodeficiency. (2 Marks)

c. Briefly explain the FOUR (4) causes of secondary immunodeficiency. (6 Marks)

PART B : ESSAY QUESTIONS (20 MARKS)

Answer TWO (2) out of FOUR (4) questions only.

Question 1

a. State the comparison between T dependent antigen and T independent antigen. (4 Marks)

b. Briefly explain the comparison between cytotoxic T cells and helper T cells. (6 Marks)

Question 2

a. Define humoral immunity? (2 Marks)

b. Briefly explain the process of humoral immunity production. (8 Marks)

Question 3

a. What are the properties of an ideal vaccine should have? (2 Marks)

b. Briefly explain FOUR (4) types of vaccines available today. (8 Marks)

Question 4

Discuss the process of vascular dilation and smooth muscle contraction that occur in Type I Hypersensitivity? (10 Marks)

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