Question 1

Which of the following best explains why adaptive immunity takes longer to mount than innate immunity?

Accepted Answer

Adaptive immunity requires the activation and clonal expansion of specific lymphocytes after antigen recognition.

Question 2

A patient is exposed to a novel virus. Which of the following steps occurs FIRST in the adaptive immune response?

Accepted Answer

Antigen presentation by dendritic cells to T cells

Question 3

Which of the following statements about antigen-presenting cells (APCs) is CORRECT?

Accepted Answer

APCs present antigens to T cells using MHC II molecules.

Question 4

A patient with a genetic defect preventing the expression of MHC I molecules would have the most difficulty with which of the following immune functions?

Accepted Answer

Destruction of virus-infected cells by cytotoxic T cells

Question 5

Which of the following best describes the process of isotype switching in B cells?

Accepted Answer

A plasma cell changes from producing IgM to producing IgG antibodies during the course of an infection.

Question 6

A child receives a DTaP vaccine and is exposed to pertussis bacteria three weeks later. Which antibody response would you expect to be most prominent?

Accepted Answer

A rapid and high-titer IgG response

Question 7

Which of the following is a function of helper T (TH) cells in the adaptive immune response?

Accepted Answer

They secrete cytokines that activate B cells and cytotoxic T cells.

Question 8

A patient with DiGeorge Syndrome lacks a thymus. Which of the following immune responses would be most severely impaired?

Accepted Answer

Response to T-dependent antigens

Question 9

Which of the following best describes the role of memory cells in adaptive immunity?

Accepted Answer

They enable a faster and stronger response upon re-exposure to the same antigen.

Question 10

Which of the following antibody isotypes is most likely to be elevated in a patient experiencing an anaphylactic reaction to bee venom?

Accepted Answer

IgE

Question 11

A cytotoxic T cell (CD8+) recognizes a cell displaying a viral peptide on MHC I. What is the next step in the immune response?

Accepted Answer

The cytotoxic T cell releases perforin and granzymes to induce apoptosis in the infected cell.

Question 12

Which of the following best explains why matching MHC molecules is critical for organ transplantation?

Accepted Answer

Mismatched MHC molecules are recognized as foreign, leading to immune rejection of the transplanted tissue.

Question 13

Which of the following is TRUE regarding the difference between T-dependent and T-independent antigens?

Accepted Answer

T-dependent antigens require helper T cell involvement for full B cell activation, while T-independent antigens do not.

Question 14

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies coat pathogens, enhancing their recognition and uptake by phagocytes.

Question 15

A patient is born with a mutation in the CD8a gene, resulting in a lack of functional CD8+ T cells. Which infection would this patient be most susceptible to?

Accepted Answer

Viral infections such as Epstein-Barr Virus

Question 16

Which of the following pairs of molecules do NOT directly interact with one another during the adaptive immune response?

Accepted Answer

BCR and TCR

Question 17

Which of the following is the correct order of events in the adaptive immune response?

Accepted Answer

Antigen presentation → Lymphocyte activation → Lymphocyte proliferation and differentiation → Antigen elimination and memory

Question 18

Which of the following best describes the function of IgA antibodies?

Accepted Answer

They are prevalent in mucous membranes and secretions, providing protection at mucosal surfaces.

Question 19

A patient is exposed to the same strain of Rhinovirus 18 months after an initial infection. Which component of the immune system is primarily responsible for the rapid and effective response?

Accepted Answer

Memory B cells

Question 20

Which of the following best explains why superantigens can be dangerous to the host?

Accepted Answer

They activate large numbers of T helper cells, leading to excessive cytokine release and potential shock.

Adaptive Immunity: Mechanisms, Cells, and Antibody Responses

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