Maximum score: 96%
Minimum score: 30%
Approximate scale:
96-85 = A
84-62 = B
61-51 = C
50-40 = D
39-30 = F
| Average score: 64% Maximum score: 96% Minimum score: 30% Approximate scale: 96-85 = A 84-62 = B 61-51 = C 50-40 = D 39-30 = F |
|
Questions numbered 1 through 25 count 2 points each (50 points).
| B | 1. | (1) | The role of complement component C2a in mediating inflammation. |
| (2) | The role of complement component C4a in mediating inflammation. | ||
| B | 2. | (1) | The lifespan of a plasma cell. |
| (2) | The lifespan of a memory cell. | ||
| A | 3. | (1) | The ability of Factor I to inhibit the production of C3b by physically cleaving cell-bound C3b. |
| (2) | The ability of Protein H to inhibit the production of C3b by physically cleaving cell-bound C3b. | ||
| C | 4. | (1) | The ability of the C3bBb complement complex to cleave C3. |
| (2) | The ability of the C4b2b complement complex to cleave C3. | ||
| B | 5. | (1) | The number of mice that could be killed using 1 milligram of a toxin with an LD50 of 1 milligram. |
| (2) | The number of mice that could be killed using 1 milligram of a toxin with an LD50 of 1 microgram. | ||
| A | 6. | (1) | The role of the spleen in the collection of blood-borne antigens. |
| (2) | The role of the lymph nodes in the collection of blood-borne antigens. | ||
| A | 7. | (1) | The ability of most exotoxins to elicit an antibody response. |
| (2) | The ability of most endotoxins to elicit an antibody response. | ||
| A | 8. | (1) | The number of T-cells that express the CD3 surface protein. |
| (2) | The number of T-cells that express the CD4 surface protein. | ||
| B | 9. | (1) | The overall effect on the immune system produced by the congenital defect known as hypogammaglobulinemia. |
| (2) | The overall effect on the immune system produced by the congenital defect known as DiGeorge syndrome. | ||
| B | 10. | (1) | The role of covalent bonds in antibody-antigen interactions. |
| (2) | The role of hydrogen bonds in antibody-antigen interactions. | ||
| A | 11. | (1) | The importance of humoral factors in preventing disease caused by Streptococcus pneumoniae. |
| (2) | The importance of humoral factors in preventing disease caused by Mycobacterium tuberculosis. | ||
| B | 12. | (1) | The role of IgM in helping to protect a fetus in utero. |
| (2) | The role of IgG in helping to protect a fetus in utero. | ||
| B | 13. | (1) | The importance of macrophages to the acquisition of an immediate hypersensitivity. |
| (2) | The importance of mast cells to the acquisition of an immediate hypersensitivity. | ||
| A | 14. | (1) | The role of CD8 in stabilizing the interaction between a T-cell receptor and Class I MHC. |
| (2) | The role of CD8 in stabilizing the interaction between a T-cell receptor and Class II MHC. | ||
| A | 15. | (1) | The amount of evidence suggesting that the condition referred to as pemphigus results from a Type II hypersensitivity. |
| (2) | The amount of evidence suggesting that the condition referred to as pemphigus results from a Type III hypersensitivity. | ||
| C | 16. | (1) | The number of amino acids that comprise the variable region of an immunoglobulin light chain. |
| (2) | The number of amino acids that comprise the variable region of an immunoglobulin heavy chain. | ||
| B | 17. | (1) | The role of IgG in the mechanism described for an Immediate Hypersensitivity. |
| (2) | The role of IgG in the mechanism described for a Cytotoxic Hypersensitivity. | ||
| B | 18. | (1) | The role of activated macrophages in the elimination of an extracellular bacterium. |
| (2) | The role of activated macrophages in the elimination of an intracellular bacterium. | ||
| C | 19. | (1) | The ability of a rabbit to produce antibodies directed against the isotypic determinants of human immunoglobulin IgG. |
| (2) | The ability of a rabbit to produce antibodies directed against the allotypic determinants of human immunoglobulin IgG. | ||
| B | 20. | (1) | The probability that an epitope derived from an extracellular bacterium would be presented to a T-cell via a Class I MHC molecule. |
| (2) | The probability that an epitope derived from an extracellular bacterium would be presented to a T-cell via a Class II MHC molecule. | ||
| A | 21. | (1) | The probability that antibody excess might occur when a person is exposed to a virus from which they have recently recovered. |
| (2) | The probability that antigen excess might occur when a person is exposed to a virus from which they have recently recovered. | ||
| A | 22. | (1) | The role of perforin in the mechanism of cell killing by cytotoxic T-cells. |
| (2) | The role of properdin in the mechanism of cell killing by cytotoxic T-cells. | ||
| B | 23. | (1) | The probability that an extracellular organism would produce a chronic disease. |
| (2) | The probability that an intracellular organism would produce a chronic disease. | ||
| A | 24. | (1) | The probability that antibodies produced against certain Rickettsia will cross-react with antigens from Proteus. |
| (2) | The probability that antibodies produced against certain Rickettsia will cross-react with antigens from Treponema. | ||
| A | 25. | (1) | The molecular weight of the Class I MHC alpha chain. |
| (2) | The molecular weight of the Class II MHC alpha chain. |
Questions 26-29: Correctly match the CELL TYPE on the left with its appropriate MOLECULE(S) listed on the right. | |||||
| E | 26. | B-cell | A. | Class II MHC | |
| D | 27. | T-cell | B. | Fc receptor | |
| G | 28. | Macrophage | C. | C3b receptor | |
| B | 29. | K-cell | D. | TCR | |
| E. | Both A and B | ||||
| F. | Both B and C | ||||
| G. | A, B and C | ||||
| H. | None of the above | ||||
Questions 30-33: Correctly match the TYPE OF HYPERSENSITIVITY listed on the left with its appropriate CHOICE(S) listed on the right. | |||||
| G | 30. | Type I | A. | Involves antibodies that react with "self" antigens | |
| A | 31. | Type II | B. | Cause of "serum sickness" | |
| F | 32. | Type III | C. | Koch's phenomenon | |
| C | 33. | Type IV | D. | Can be ascertained by the observance of an "Arthus" reaction | |
| E. | Both A and B | ||||
| F. | Both B and D | ||||
| G. | None of the above | ||||
| Questions 34-38: Correctly match the STATEMENT listed on the left with its appropriate IMMUNOGLOBULIN listed on the right. | |||||
| C | 34. | Found in a pentameric form | A. | IgA | |
| A | 35. | Found in secretions such as tears | B. | IgG | |
| B | 36. | Produced in large amounts during the secondary response | C. | IgM | |
| E | 37. | Binds specifically to the surface of mast cells | D. | IgD | |
| B | 38. | Involved in opsonization | E. | IgE | |
39. List three (3) of the four characteristics that define an antigenic substance (3 points).
| 1) large molecular weight, 2) complex structure, 3) accessible to the immune system, 4) foreign (not "self") |
40. List three (3) ways that cytotoxic T-cells (CTLs) are thought to exert their cytotoxic activity (3 points).
| 1) release of perforin, 2) release of enzymes, 3) release of lymphokines/cytokines |
41. Draw the general structure of an IgG immunoglobulin showing i) the Fc region, ii) the antigen binding region, iii) the constant regions and iv) the variable regions (4 points).
42. Describe the concept of antigen cross-reactivity. Use a picture to illustrate the concept (4 points).
| Cross-reactivity occurs when 2 or more antigens can bind to a single antibody. As shown in the picture, antibody produced in response to antigen 1 can bind antigen 2 but with a reduced affinity. |
43. A researcher studying a particular antigen-antibody reaction performed the following experiment. First, five (5) ml of serum containing the antibody was added to each of five different tubes. Then, different amounts of the antigen was added to each tube. After centrifugation, the amount of Ag-Ab precipitate was measured and the results are shown in the table (4 points).
| Amount of Antigen (arbitrary units) | 1 | 2 | 3 | 4 | 5 |
| Weight of Precipitate | 1 mg | 2 mg | 4 mg | 2 mg | 1 mg |
Use these data to draw a graph. On the graph, indicate the regions of 1) antibody excess, 2) antigen excess and 3) equivalence.
44. A laboratory technician was given a sample of blood from a patient suspected of having a viral infection and asked to test for the presence of anti-viral antibody. The technician used a complement fixation assay for this determination. Below, list the additional reagents that the technician added to the patient's serum IN ORDER OF ADDITION. Also, describe the end result if 1) the patient's serum contained anti-viral antibody or 2) the patient's serum did not contain anti-viral antibody (6 points).
| List and order of reagents: |
| 1) Patient's serum |
| 2) Specific Viral Antigen |
| 3) Sheep Red Blood Cells (SRBC) |
| 4) Anti-SRBC antibody |
| 5) Complement |
| Results: |
| 1) if the patient's serum contained anti-viral antibody the result would be: |
| Minimal SRBC lysis |
| 2) if the patient's serum did not contain anti-viral antibody the result would be: |
| Maximum SRBC lysis |