Transcript
White Version Answer Key:
1. A
2. A
3. ALL ANSWERS
4. C
5. D
6. E
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8. D
9. B
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14. D
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17. E
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19. D
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35. A
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41. B
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43. B
44. A
45. B
46. E
Spring 2009
Exam II
Questions 1-20 (1 point each): Select one answer for each question.
1. What MHC molecule is needed to activate helper T cells?
a. the same MHC molecule that is stabilized by invariant chain b. the same MHC molecule that activates T cells
c. the same MHC molecule that presents peptides from intracellular antigens
d. the same MHC molecule that presents peptides produced by the proteosome e. c and d
2. What is the function of CD4 and CD8 during T cell activation?
a. to bind directly to the MHC molecule on the antigen presenting cell b. to bind directly to the TCR and stabilize the TCR
c. to bind directly to the antigen on the antigen presenting cell d. to bind directly to CD3
e. to bind directly to adhesion molecules to stabilize the interaction with the APC
3. What is the correct order of gene rearrangement during B cell development?
a. VH, joins JH, then the VJ segment joins DH, then VL joins JL
b. VH, joins JH, then VL joins JL and the VJ segment joins DL
c. VH, joins JH, then VL joins DL and the VD segment joins JL
d. VH, joins DH, then the VD segment joins JH, then VL joins JL
e. VH, joins JH, then VL joins JL
4. What occurs during negative selection of T cells?
a. T cells that bind to self peptide and self MHC with low affinity die
b. T cells that bind to foreign peptide and self MHC with low affinity die c. T cells that bind to self peptide and self MHC with high affinity die
d. T cells that bind to self peptide and self MHC with high affinity live e. a and b
5. What MHC molecule uses 2microglobulin?
a. the same MHC molecule that presents small peptides
b. the same MHC molecule that presents large peptides
c. the same MHC molecule that is recognized by the TCR on cytotoxic T cells d. a and c
e. b and c
6. What does the term “allelelic exclusion” describe in the development of B cells?
a. the maternal allele of
b. the maternal allele of light chain is expressed in at least 90% of B cells
c. only the maternal allele of heavy chain is produced while both the maternal and paternal alleles of light chain are produced in a B cell
d. productive rearrangement of heavy chain gene segments stops rearrangement of light chain gene segments e. productive rearrangement of heavy chain gene segments on one allele stops rearrangement of gene
segments on another allele
7. What occurs when the pre-TCR is expressed on a T cell?
a. the T cell stops rearranging the chain genes
b. the T cell stops expressing CD4 and CD8 on its surface c. the T cell activates Tdt
d. two of the above answers are correct
e. all of the above answers are correct
8. How do the adhesion molecules on a T cell change during activation?
a. the adhesion molecules change shape and bind directly to the antigen b. the adhesion molecules change shape and bind directly to CD4/CD8
c. the adhesion molecules change shape and move far away from the TCR
d. the adhesion molecules change shape and increase their affinity for their ligands
e. the adhesion molecules change shape and transmit a signal to the nucleus of the cell
9. Some viruses inhibit TAP from functioning. How will this affect the immune response to the virus?
a. helper T cells could not be activated by the virus
b. cytotoxic T cells could not be activated by the virus
c. macrophages would be unable to phagocytose the virus d. antibodies would be unable to bind to the virus
e. there would be no effect on the immune response
10. Where would you find IgM+ cells in the bone marrow?
a. near the hard bone
b. near the central artery
c. mixed with other cells randomly throughout the bone marrow d. mixed with the CD43+ cells
e. nowhere in the bone marrow, they would only be found in the secondary lymphoid organs
11. What is the difference between CD28 and CD3?
a. CD28 binds to antigen peptides and CD3 does not bind to antigen peptides b. CD3 binds to antigen peptides and CD28 does not bind to antigen peptides
c. CD28 binds to a ligand on the antigen presenting cell and CD3 does not bind to a ligand d. CD3 binds to a ligand on the antigen presenting cell and CD28 does not bind to a ligand
e. none of the above
12. During development in the bone marrow, B cells go through 3 checkpoints. The third checkpoint occurs during the
transition from immature B to mature B. What is being “checked” during this time?
a. if the immature B cell makes an unproductive rearrangement of light chain genes, the cell will die b. if the immature B cell makes a productive rearrangement of light chain genes, the cell will live
c. if the immature B cell binds to self antigens with high affinity, the immature B cells usually dies d. if the immature B cell binds to self antigens with high affinity, the immature B cell usually lives
e. more than one of the above answers is correct
13. What is the difference between MHC class I and MHC class II?
a. MHC I has one peptide binding site and MHC II has two peptide binding sites b. MHC I binds to one TCR and MHC II binds to two TCRs
c. MHC I is expressed on both B and T cells, MHC II is expressed on B cells but not on T cells d. MHC I is transcribed from one gene segment, MHC II is transcribed from two gene segments e. none of the above
14. How are CD8+ T cells activated?
a. the TCR on the T cell binds to MHC class II and antigen peptide on an antigen presenting cell b. the TCR on the T cell binds to MHC class I and a whole antigen
c. the TCR on the T cell binds to MHC class II and a whole antigen
d. the TCR on the T cell binds to MHC class I and antigen peptide on an antigen presenting cell e. none of the above
15. What is the difference between T cells and T cells?
a. the TCR on T cells binds to MHC I or MHC II, the TCR on T cells only binds to MHC I
b. the TCRs switch to TCRs after a T cell is activated
c. T cells develop in the thymus, T cells developed completely in the bone marrow d. T cells are CD4+ or CD8+, T cells are CD4- and CD8-
e. T cells activate B-1 cells, T cells activate B-2 cells
16. You have four experimental groups with four different peptides in a cytotoxicity assay. The amount of radioactivity found in the supernantant of each group is shown below. Based on this data, which group of APCs had the peptide that would be the least effective as a vaccine?
Group Amount of Radioactiity
A 100 cpm
B 500 cpm
C 200 cpm
D 50 cpm
17. What is the difference between pro-B cells and pro-T cells?
a. pro-B cells only use RAG for gene rearrangement, pro-T cells only use Tdt b. pro-B cells proliferate, pro-T cells do not proliferate
c. pro-B cells have an antigen receptor on their surface, pro-T cells do not d. pro-T cells are “double positive”, pro-B cells are “double negative”
e. pro-T cells rearrange gene segments, pro-B cells rearrange gene segments
18. When RAG binds to two RSS sequences, what occurs?
a. a hepatmer-12 spacer-nonamer sequence is linked to a nonamer-23 spacer-heptamer sequence b. the hepatmer sequences are linked to form a coding joint
c. the noname sequences are linked to form a coding joint d. two of the above are correct
e. none of the above are correct
19. When an antigen is phagocytosed, what happens to the antigen?
a. the proteosome breaks the antigen apart into peptides
b. the antigen peptides are loaded onto the MHC molecules in the endoplasmic reticulum c. the antigen peptides are stabilized by CLIP until they bind to MHC molecules
d. the antigen peptides and MHC are used to activate helper T cells e. more than one of the above answers are correct
20. What cells survive during positive selection of T cells?
a. T cells that bind to self peptide and self MHC with high affinity b. T cells that bind to self peptide and self MHC with low affinity c. T cells that have no affinity for self peptide and self MHC
d. T cells that bind to foreign peptide and self MHC with high affinity e. b and c
Questions 21-45: True/False. Select one answer for each question. (1 point/question)
21. T cells will not present a TCR on their plasma membrane without CD3. a. True b. False
22. In the absence of Ig , an animal will not produce IgA, but will still be able to produce IgM and IgD. a. True b. False
23. The (alpha) chain encoded by the maternal allele of HLA-A gene can pair with the (beta) chain encoded by the paternal allele of the HLA-B gene.
a. True b. False
24. Double negative thymocytes are found in the cortex and single positive thymocytes are found in the medulla. a. True b. False
25. The same number of gene segments are found in light chain genes and alpha ( ) chain genes. a. True b. False
26. All of the professional APCs have constituitively high levels of CD80 and CD86 on their surface. a. True b. False
27. If a patient’s haplotype includes the gene: HLA-DPA 06 25, the patient has an alpha chain from a MHC II molecule that is recognized by an antibody in group 6.
a. True b. False
28. Immature dendritic cells have fewer MHC molecules on their surface than mature dendritic cells. a. True b. False
29. The cytoplasmic tail of the TCR, CD3, and (zeta) chain all contain ITAMs that recruit and activate kinases. a. True b. False
30. HAT media kills plasma cells and mutant myeloma cells, but it does not kill B cell hybridomas. a. True b. False
31. A CD43+ B220- cell could differentiate into a B cell, T cell, or dendritic cell depending on what growth factors and signals it receives.
a. True b. False
32. Without invariant chain, MHC I and MHC II would compete for the same ligands within a specific location of a cell. a. True b. False
33. The HLA-DMB gene encodes a beta chain that binds to CD4 and the 2-microglobulin gene encodes a beta chain that binds to CD8.
a. True b. False
34. Pro-T cells can be separated from pre-T cells based on their expression of CD4 and/or CD8. a. True b. False
35. Without the (lambda) 5 gene, mice would have a normal number of pro-B cells, but a decreased number of pre-B
cells.
a. True b. False
36. Calnexin stabilizes the MHC I alpha chain alone (not associated with another chain) in the endoplasmic reticulum. a. True b. False
37. B-1 cells are predominantly found in the peritoneal cavity where they secrete IgG (known as natural antibodies)
without being stimulated by an antigen. a. True b. False
38. Mature white blood cells can be killed by cytotoxic T cells but mature red blood cells can not be killed by cytotoxic T
cells.
a. True b. False
39. Antibodies and T cell receptors have the same number of antigen binding sites but only one (either the TCR or antibodies) can be secreted.
a. True b. False
40. Without terminal deoxynucleotidyl transferase (Tdt), cells would lack N nucleotides, but would still have P nucleotides. a. True b. False
41. In order for an immature B cell to differentiate into a mature B cell, the immature B cell needs to use RAG again to rearrange the C gene segments.
a. True b. False
42. Mice that lack cathepsin also lack CLIP. a. True b. False
43. The first step in an ELISA is to use an enzyme-labeled antigen to capture a specific antibody. a. True b. False
44. When a peptide binds to a MHC molecule, the anchor residues interact directly with the peptide binding motif. a. True b. False
45. The only cells in an animal that express MHC II are B cells, macrophages, and dendritic cells. a. True b. False
Extra Credit:
46. The function of the ITSM region in the SLAM molecule is:
a. to recruit enzymes that suppress activation of T cells b. to recruit enzymes that stimulate activation of T cells
c. to bind to and block the ITAM in the cytoplasmic tail of the TCR
d. to bind to and block the ITIM in the cytoplasmic tail of the TCR
e. to help activate T cells and to help inhibit T cells
