1. ANSWER EITHER “1A” OR “1B” POINTS WILL BE DEDUCTED …



1. Match each immunoglobulin isotype in a through d with the description(s) listed below (1-13) that are true about that isotype. Some of the descriptions may apply to more than one isotype; others may not apply to any isotype.

a. _____________ IgA b. _____________IgE c. __________IgG d. ___________ IgM.

1. Secreted form is a pentamer of the basic H2L2 unit.

2. binds to Fc receptors on mast cells

3. Multimeric forms have J-chains.

4. Present on the surface of mature, unprimed B cells

5. The most abundant Ig class in serum.

6. Major antibody in secretions such as saliva, tears and colostrum.

7. Present on the surface of immature B cells.

8. The first serum antibody made in a primary immune response.

9. Plays an important role in protecting against pathogens that invade through the gut or respiratory mucosa.

10. Can participate in ADCC.

2. Indicate whether each of the following statements is true or false. If you think a statement is false. explain why.

a. Indirect immunofluorescence is a more sensitive technique than direct immunofluorescence.

b. Most antigens induce a polyclonal response.

c. A papain digest of anti-SRBC antibodies can agglutinate sheep red blood cells (SRBC).

d. A pepsin digest of anti-SRBC antibodies can agglutinate sheep red blood cells (SRBC).

e. Indirect immunofluorescence can be performed using a Fab fragment as the initial nonlabeled antibody.

f. For precipitation to occur, both antigen and antibody must be multivalent.

g. The Ouchterlony technique is a quantitative precipitin technique.

3. For each incomplete statement below (a-d), select the phrase(s) that correctly completes the statement. More than one choice may be correct.

3a. Recombination of Ig gene segments serves to:

1. promote Ig diversification

2. assemble a complete Ig coding sequence

3. allow changes in coding information during B-cell maturation

4. increase the affinity of Ig for antibody

5. all of the above

3b. Somatic mutation of Ig genes accounts for :

1. allelic exclusion

2. class switching from IgM to IgG

3. affinity maturation

4. all of the above

5. none of the above

3c. The frequency of somatic mutation in Ig genes is greatest during:

1. differentiation of pre-B cells into mature B cells

2. differentiation of pre-T cells into mature T-cells

3. generation of memory B cells

4. antibody secretion by plasma cells

5. none of the above

3d. Kappa and lambda light chain genes

1. are located on the same chromosome

2. associate with only one type of heavy chain

3. can be expressed by the same B cell

4. all of the above

5. none of the above

3e. Generation of combinatorial diversity among Igs involves

1. mRNA splicing

2. DNA rearrangement

3. recombination signal sequences

4. one-turn/two-turn joining rule

5. switch sites

5. Indicate whether each of the properties listed below applies to the T-cell receptor (TCR), B-cell Ig (IG) , or both (B).

1. is associated with CD3

2. is monovalent

3. exists in membrane-bound and secreted forms

4. contains domains with the Ig fold

5. is MHC restricted

6. exhibits diversity generated by imprecise joining of gene segments

7. exhibits diversity generated by somatic mutation

6. Indicate whether each of the following statements is true or false. If you think a statement is false, explain why.

a) A monoclonal antibody specific for b2 microglobulin can be used to detect both class I MHC and class II MHC molecules on the surface of cells.

b) Antigen presenting cells express both class I and class II MHC molecules on their membrane.

7. (10 pts) Cyclosporin A is a powerful immunosuppressive drug that now is given to transplant recipients. Describe how this drug suppresses the immune response.

Would this drug have to be given continuously or occasionally? Why?

8. State ONE type of cell that responds to each of the following cytokines and the nature of the response (5 pts)

IL-1

IL-2

IL-3

IL-4

IL-6

9. How do the two subsets of TH cells differ in their roles in the immune system and in the cytokines they produce? (5 pts)

10. Describe the primary signals required to activate naive B cells. (5pts)

What additional signals, if any, are needed to stimulate proliferation and differentiation of activated B cells? (5 pts)

11. What is the costimulatory signal in the generation of CTL activity? (4 pts)

What cell membrane molecules are involved in generating this signal? (4 pts)

What is the direct consequence of the costimulatory signal? (4 pts)

How does this consequence impact the generation of CTL activity? (4 pts)

12. HIV, the virus that leads to AIDS, infects and leads to a decrease in the number of CD4+ cells. (15 pts)

What effect, if any, would HIV have on the DTH response?

Could this effect be involved in the susceptibility of HIV+ individuals to pathogens that are successfully dealt

with by HIV- individuals? If so, how?

13. Would you expect a C1 or a C3 complement deficiency to be more serious clinically? Why? (5 pts)

14. Match each complement component(s) or reaction (a-l) with the appropriate activity or description listed below (1-12). The numbers may be used once, more than once, or not at all. (15 pts)

a) C3b

b) C1, C4, C2 and C3

c) C9

d) C3, factor B and factor D

e) C1q

f) C4b2a3b

g) C5b, C6, C7, C8 and C9

h) C3 C3a + C3b

i) C3a, C5a and C5b67

j) C3a, C4a and C5a

k) C4b2a

l) C3b +B C3bBb + Ba

1. Major amplification step

2. early components of alternative pathway

3. components of the membrane- attack complex

4. mediates opsinization

5. early components of classical pathway

6. has perforin-like activity

7. binds to Fc region of antibodies

8. chemotatic factors

9. has C3 convertase activity

10. has C5 convertase activity

15. What feature(s) of the Sabin polio vaccine cause it to produce an immune response that includes IgA? (5 pts)

16. What is an attenuated organism? What are the advantages and disadvantages of using such an organism as a vaccine? (15 pts)

17. (10 pts.) What are the two stages in the process of graft rejection?

What occurs in each stage?

18. List the major classes of immunodeficiency diseases, and the name, immune system deficiency and possible mechanism of production of one example of one of the classes. (10 pts.)

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