Part I. Clearly state the meaning / function for each of the terms, abbreviations, cell types or organs listed below. Be sure to include a detailed enough answer to indicate your full understanding of the definition you provide

1. HAART: is known as highly active anti-retroviral therapy. It functions to decrease the

2. perforin:

3. localized anaphylaxis:

4. antigenic variation:

5. M cells:

6. primary immunodeficiency:

7. seroconversion:

8.  herd immunity:

9. ITAM:

10. commensal microorganism:

Part II: Decide whether each of these statements is true or false, and then briefly explain why. Be sure to include a detailed enough answer to indicate your full understanding of the definition you provide;

1.   Celiac disease and the tuberculin test are good examples of type III hypersensitivity reactions

2.   CD3 on T cells is functionally analogous to Igá/Igâ on B cells.

3.   Memory B cells do not require T cell help.

4.   A live attenuated vaccine would not likely require aIDition of an adjuvant.

5.   Blocking of the Fas-Fas ligand interaction is likely to completely inhibit Tc responses.

6.   An immature B cell that readily binds to a bone marrow stromal cell will likely exit the bone marrow and migrate to a secondary lymphoid organ for further maturation.

7.   Our capacity to generate naïve T cells diminishes as we age.

8.   The pTá on thymocytes is functionally analogous to the surrogate light chain on pre-B cells.

9.   Type O individuals can accept blood from type A, type B and type AB donors.

10. Systemic anaphylaxis is a life-threatening allergic reaction.

Part III:

1. Briefly answer each of the following questions:

a. What is the hygiene hypothesis?

b. How might this hypothesis influence the development of new treatment strategies for type I hypersensitivities?

2. T cells develop and are “educated” in the thymus where they undergo positive and negative selection. Explain what occurs during positive and negative selection; and why these selection processes are important. In your answers be sure to specifically explain what particular impact these selection processes have on T cell development. AIDitionally be sure to explain the role of the AIRE protein.

3. Describe specific steps in the HIV life cycle to help answer the following questions: 

a.   Why do infected patients experience a prolonged latency period between infection and full blown AIDS?

b.   What are three ways that HIV evades the immune system?

c.   Why do patients ultimately succumb to opportunistic infections?

d.   Why might individuals with mutations in the CCR5 chemokine receptor be resistant to infection by HIV?

4. Most B cell responses require T cell help while others do not.

a. Distinguish between TD, TI-1 and TI-2 antigens and the characteristics of the humoral responses which they induce.

b. Describe the steps involved in TD antigen activation of B cells.  Be sure to explain the roles of the various cell surface molecules involved in the activation process.

5. Distinguish between Th1, Th2 and Treg cells by answering the following questions:

a. What are the key effector functions of these cells?

b. How could these three cell types be clearly and simply distinguished from each other in an experimental laboratory?

c. How and where do these different cell types differentiate to their mature functional characteristics?