Immunology Mcqs-iv (gate Helpline)

GATE HELPLINE IMMUNOLOGY MCQs-IV

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1. Jenner observed that milkmaids who were infected with cowpox were later immune to smallpox infections. This is an example of a. acquired immunity of barrier skin cells. b. active immunization with a non-related organism that causes similar symptoms. c. memory response to a cross-reactive antigen. d. passive immunization from contact with cow's milk antibodies. 2. Macrophages generally kill the bacteria they phagocytosis by fusing lysosomes containing digestive enzymes with the phagocytic vesicle. In the case of pathogens which block this fusion, pathogen killing can still be achieved through the effector function of a. B cells. b. complement. c. cytotoxic T cells. d. Th cells. 3. Phagocytosis a. can be stimulated by antigen binding to complement or antibody. b. is an antigen-specific process. c. must be preceded by antigen processing. d. rids the body of virus-infected cells. 4. Several friends who went on a picnic together developed vomiting and diarrhea from eating potato salad contaminated with Staphylococcus aureus enterotoxin. Effects of the toxin could best be counteracted by a. antibody binding and neutralization of the toxin. b. antibody opsonization and phagocytosis of S. aureus. c. antibody opsonization and phagocytosis of the toxin. d. B cell binding to S. aureus. 5. Which of the following statements is FALSE? a. An example of passive Humoral immunity is treatment with horse anti-snake venin. b. Antigen recognized by helper T cells must be associated with Class II MHC molecules on the surface of professional APC. c. Each lymphocyte has many antigen binding receptors, each receptor capable of binding the same antigen. d. Recognition and killing of virus-infected cells by cytotoxic T cells is an example of adaptive immunity. 6. The ability of an antigen to induce an immune response does NOT depend on the antigen's a. degree of aggregation. b. dose. c. size. d. usual presence in the body.

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7. Alum is an effective adjuvant because it a. disaggregates the antigen. b. is immunogenic for stem cells c. is immunogenic for T cells. d. slows the release of antigen. e. transports antigen into the cytoplasm of antigen-presenting cells. 8. Antibody cross-reactivity is demonstrated by antibody binding to a. a hapten. b. a hapten-carrier complex. c. an antigen that is structurally similar to the immunogen d. the immunogen. 9. The antibiotic penicillin is a small molecule that does not induce antibody formation. However, penicillin binds to serum proteins and forms a complex that in some people induces antibody formation resulting in an allergic reaction. Penicillin is therefore a. an antigen. b. a hapten. c. both an antigen and a hapten. d. both an antigen and an immunogen. 10. Antigen entering the body in a subcutaneous injection activates its specific lymphocytes in the a. blood circulation. b. draining lymph nodes. c. MALT. d. skin. 11. During the lag period between antigen contact and detection of adaptive immunity, a. antigen is hidden from the immune system in macrophages. b. cellular immunity can be detected but antibodies cannot. c. innate immune effectors are eliminating antigen. d. innate immunity blocks the activation of adaptive immune effector cells. 12. The immune response to a booster vaccine is called a. cellular response. b. innate response. c. primary response. d. secondary response.

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13. Lymphocytes are activated by antigen in the a. blood stream. b. bone marrow. c. liver. d. lymph nodes. 14. A molecule that can be covalently linked to a non-immunogenic antigen to make it an immunogen is called a. adjuvant. b. carrier. c. hapten. d. mitogen. 15. A polyclonal antibody response a. is not antigen-specific. b. is produced only in response to polymeric antigens. c. is produced by several B cells recognizing different epitopes on the same antigen. d. occurs during the lag phase of the immune response. 16. Very low doses of antigen may induce a. a secondary response. b. hypersensitivity. c. immunological ignorance. d. low zone tolerance. 17. A virus vaccine that can activate cytotoxic T cells MUST contain a. a high dose of virus particles. b. an adjuvant to stimulate T cell division. c. foreign MHC. d. virus peptides. 18. Which statement about antigen epitopes is FALSE? a. An epitope may be shared by two different antigens. b. A protein molecule usually contains multiple epitopes. c. B cells bind only processed antigen epitopes. d. Epitopes may be linear or assembled. 19. CD antigens a. allow leukocytes to recognize antigen. b. are each expressed on only one cell type. c. are expressed on immune cells by immunologists to "mark" them for separation. d. function as receptors for cytokine and CAMs.

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