Test 88    (immunology)

1. The following are true about cell-mediated immunity:

a. antigen-specific function is the role of the 
    T-lymphocytes

b. cell-mediated immunity can activate the complement
     system

c. it is responsible for the delayed hypersensitivity 
    reaction.

d. g-interferon is an important mediator of B-cell 
    activation.

e. acute graft rejection is caused by cell-mediated 
    immunity.

Answera.F   b.T  c.F  d.F  e.F
T cells either signal B-cells to make antibody via cytokines or membrane molecules production or kill virally infected cells or tumour cells.
The complement system may be activated in the absence of antibodies.
alpha and beta interferon inhibit viral replication, 
activate the natural killer cells and up-regulate class I MHC.

2. The following are useful in the diagnosis of HIV infection:

a. polymerase chain reaction

b. antibodies by enzyme-liked immunoadsorbent assay

c. P24 protein assay

d. immunoglobulin assay

e. CD4:CD8 ratio

Answera.T   b.T   c.T  d.T  e.T

3. The following are true about chemicals involved in allergic reaction:

a. thromboxane -leukocyte activation

b. prostaglandin-2 - vasodilatation

c. platelet-activating factor - leukocyte activation

d. heparin - augments inactivation of prostaglandins

e. histamine - increases cAMP.

Answera.F   b.T  c.F  d.F  e.T
Thromboxane causes platelet aggregation, constriction of microvasculature and bronchoconstriction.
Platelet-activating factor causes neutrophil 
deactivation, aggregation and enzyme release.
Heparin augments inactivation of histamine.
.

4. In AIDS, the following abnormalities are seen:

a. persistent lymphopenia

b. increased g interferon production in response
    to antigens

c. decreased interleukin-2 production

d. impaired delayed cutaneous hypersensitivity reactions

e. absolute depletion of CD8 lymphocytes.

Answera.T  b.F  c.T  d.T   e.F
Production of gamma interferon is decreased.
There is absolute depletion of CD4 lymphocytes.

5. The following are true:

a. Ig G crosses the placenta

b. thymus gland is responsible for cellular immunity

c. C1-9 is used by the alternative complement pathway

d. eosinophils are responsible for phagocytosis

e. interleukin-1 activates B cells to produce interleukin-2

Answera.T   b.T  c.F  d.F  e.F
The alternative pathway uses C3bBD-C356789 whereas classical pathway uses C1-9.
Interleukin-1 activates T cells to produce interleukin-2.
Neutrophils and monocytes are the main phagocytes.

 
 

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