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Immunology Test #3 Review Questions
Spring 2012
1. What are kinases? How do they (in general) regulate cell-signaling events?
2. What are phosphatases? How do they (in general) regulate cell-signaling
events?
3. Differentiate between scaffolds and adaptors. Be able to give one example of
each of these types of proteins, and to tell how each is involved in a specific
cell-signaling pathway.
4. What are small G proteins? How are they activated…in general…? Be able to
give one example of a small G protein, and to tell how it is involved in a
specific cell-signaling pathway.
5. What is an SH2 domain? An SH3 domain? A pleckstrin homology domain?
What do each of these domains bind to? Be able to give at least one specific
example of a cell-signaling pathway (including names of molecules) that
involves each of these types of domains.
6. What are ubiquitin ligases? Be able to discuss two different ways..including
the pathways involved… in which these proteins can regulate an immune
response.
7. Describe, with specific examples, two different ways in which immune
response signaling pathways can be turned off, or at least down-regulated.
8. Be able to name and discuss the roles of each component of the T Cell and B
Cell receptor complexes.
9. What is an ITAM? Where are the B and T cell receptor complex ITAMs
located, and how do they get phosphorylated?
10. Discuss the role of ZAP-70 in T cell activation, including how ZAP-70 is
recruited to the T Cell Receptor complex, how it is activated, and how it in
turn activates other molecules (be able to name them).
11. What are the roles of CD4/CD8 co-receptors in T Cell signaling? How are
they recruited to the T Cell Receptor complex?
12. How to Csk and CD45 regulate Lck activation? What does Lck do?
13. How are LAT and SLP-76 recruited to the TCR complex and then activated?
What are their roles in cell signaling?
14. How is PLC- activated? Be sure to discuss the role of the TCR co-stimulatory
molecule CD28 and PI3K in this process.
15. What reaction does active PLC-catalyze?
16. Discuss the series of cellular events by which increased levels of IP3 leads to
the activation of NFAT
17. Discuss the series of cellular events by which DAG activates a small G protein
that leads to the activation of part of the AP-1 transcription factor.
18. Discuss the series of cellular events by which DAG activates PKC-θ, and how
that activation leads to the activation of both NFkB and the other half of the
AP-1 transcription factor.
19. Name the components of the B Cell Co-receptor complex, and describe their
roles in B Cell Signaling.
20. How are the Src family kinases (Blk, Fyn, Lyn) activated during B cell
activation? What do they phosphorylate once they are activated?
21. How is the Syk kinase activated and what, in turn, does it activate (and how)?
22. Describe the roles of BLNK and Btk in B cell signaling.
23. How is PLC-activated in B cells?
24. Be able to compare and contrast B cell and T cell signaling. In what ways are
they similar, and in what ways do they differ?
25. Be able to list a few other types of cells that use ITAMs for activation.
26. How does CTLA-4 regulate T cell function?
27. What are ITIMs? Give a few examples and tell their functions.
28. Be able to describe how cytokines of the hematopoietin family cause the
activation of new gene transcription (give the cell signaling events).
29. Be able to describe how binding of Fas to its ligand causes apoptosis (give the
cell signaling events).
30. Describe the intrinsic pathway of apoptosis.
31. Describe the roles of sentinels, protectors and executioners in apoptosis.
32. In which central lymphoid compartments do B and T cell development occur?
33. Be able to describe the order of rearrangements of the immunoglobulin
genes, and to tell the status of the rearrangements in each B cell
developmental stage.
34. What is allelic exclusion, and when does it happen?
35. How is somatic recombination temporarily turned off in the large pre-B cells?
36. What types of cells in the bone marrow are critical to the maturation of B
cells, and why?
37. Be able to describe the roles of IL-7, FLT3, CXCL12 and SCF in B cell
development.
38. When somatic recombination turns back on, why don’t heavy chains continue
to rearrange?
39. What is isotypic exclusion and when does it happen?
40. What is the pre-B cell receptor? Be able to discuss its structure, and to tell
how it signals the B cell. What is the result of its signaling?
41. How are E2A and EBF involved in B cell development?
42. How is Pax5 involved in B cell development?
43. Why do immunoglobulin light chains get several chances to rearrange, while
heavy chains only get one?
44. What is receptor editing, and when does it happen?
45. Define clonal deletion, clonal anergy and clonal ignorance. How does each
happen? Which of these cell types (deleted, anergic or ignorant) is of the
most concern in terms of autoimmune responses? Defend your answer.
46. In what cellular compartment does T cell selection occur?
47. What are double-negative thymocytes? What three types of cells make up
the double-negative lineage?
48. Be able to describe the normal development of  T cells.
49. What are DN1 cells, and what cell surface markers do they display?
50. Describe the order in which the TCR undergoes somatic rearrangement, and
to tell in which developmental stage each rearrangement occurs. Be sure to
also be able to state the status of CD45, Kit, CD25 and CD4/CD8 on these
cells.
51. Why can TCR light chains undergo multiple rounds of somatic
rearrangement, while the heavy chains do not?
52. In which T cell stage is the pre-T-cell receptor expressed? Describe its
structure and its role in T cell development.
53. The thymus can be divided into several compartments. Describe the
migration of developing T cells through these compartments as they mature,
and then undergo positive and negative selection.
54. Describe how positive and negative selection are thought to occur, and how
the affinity hypothesis is involved. Make sure to discuss all cell types
involved in positive and negative selection, and how selection determines the
CD4/CD8 fate of developing thymocytes.
55. Describe how signaling through the  T cell receptor and the pre-T-cell
receptor determine thymocyte fate.
56. Describe the waves of  production that occur during fetal and newborn
development, and how each gives rise to a unique population of T Cells.