Question 1

Which of the following best describes the role of MHC I molecules in adaptive immunity?

Accepted Answer

They present intracellular antigens to CD8+ T cytotoxic cells.

Question 2

A patient is exposed to a virus for the first time. Which antibody isotype is most likely to be produced first in response to this infection?

Accepted Answer

IgM

Question 3

Which of the following is a key difference between T cell and B cell antigen recognition?

Accepted Answer

B cells recognize antigens directly, while T cells require antigen presentation via MHC molecules.

Question 4

Which cytokines are primarily involved in the differentiation of TH1 cells, and what is the main function of these cells?

Accepted Answer

Interleukin 12 and interferon gamma; activate cytotoxic T cells and macrophages

Question 5

A mutation prevents the expression of CD40L on T helper cells. Which process would be most directly impaired?

Accepted Answer

Activation of B cells by T-dependent antigens

Question 6

Which of the following best explains why memory cells provide a faster and stronger response upon secondary exposure to an antigen?

Accepted Answer

Memory cells have already undergone clonal expansion and differentiation, allowing rapid activation.

Question 7

Which antibody isotype is most prevalent in mucosal secretions such as saliva and tears, and what is its main function?

Accepted Answer

IgA; neutralization of pathogens at mucosal surfaces

Question 8

A patient with a deficiency in MHC II molecules would have the most difficulty with which of the following immune processes?

Accepted Answer

Activation of helper T cells by extracellular antigens

Question 9

Which of the following steps occurs during the elimination of a virus-infected cell by a cytotoxic T cell?

Accepted Answer

Release of perforins and granzymes to induce apoptosis

Question 10

Which of the following best describes the process of clonal expansion in adaptive immunity?

Accepted Answer

A single lymphocyte divides repeatedly to produce a population of cells with identical antigen specificity.

Question 11

Which antibody isotype is most effective at crossing the placenta to provide passive immunity to a fetus?

Accepted Answer

IgG

Question 12

A bacterial polysaccharide triggers antibody production without T cell help. This is an example of which type of antigen?

Accepted Answer

T-independent antigen

Question 13

Which of the following is a function of the Fc region of an antibody?

Accepted Answer

Determining the antibody's isotype and mediating complement activation

Question 14

Which process is enhanced by antibodies through opsonization?

Accepted Answer

Phagocytosis by macrophages

Question 15

A patient is found to have high levels of IgE. Which of the following conditions is most likely present?

Accepted Answer

Parasitic infection or allergic response

Question 16

Which of the following best explains why red blood cells do not present antigens via MHC I?

Accepted Answer

They lack a nucleus and do not express MHC I molecules.

Question 17

Which of the following is a direct result of the interaction between B7 (CD80/86) on an APC and CD28 on a T cell?

Accepted Answer

Secondary co-stimulatory signal required for full T cell activation

Question 18

Which of the following best describes the outcome if a pathogen is encountered a second time after memory cells have formed?

Accepted Answer

The immune response is faster and more robust due to the presence of memory cells.

Question 19

Which of the following is NOT a function of antibodies?

Accepted Answer

Directly lysing infected host cells

Question 20

Which T cell subset is primarily responsible for suppressing immune responses after a threat has passed?

Accepted Answer

T regulatory (Treg) cells

Adaptive Immunity: T Cells, B Cells, and Antibody-Mediated Responses

Study Guide - Practice Questions