Question 1

Which of the following best describes the role of dendritic cells in the adaptive immune response?

Accepted Answer

They act as antigen-presenting cells that bridge innate and adaptive immunity.

Question 2

A patient is infected with a virus that only infects cells in the cytoplasm. Which immune response is primarily responsible for eliminating these infected cells?

Accepted Answer

Cell-mediated immunity involving cytotoxic T cells

Question 3

Which class of immunoglobulin is the first to be produced during a primary immune response and is most effective at agglutinating microbes?

Accepted Answer

IgM

Question 4

What is the main function of the variable (Fab) region of an antibody?

Accepted Answer

To bind specifically to antigens

Question 5

Which of the following best explains why IgG is important for neonatal immunity?

Accepted Answer

IgG is the only antibody class that can cross the placenta.

Question 6

A patient with a parasitic worm infection is most likely to have elevated levels of which immunoglobulin?

Accepted Answer

IgE

Question 7

Which of the following is a correct sequence of events in the activation of a B cell by a T-dependent antigen?

Accepted Answer

B cell binds antigen → B cell presents antigen with MHC II → Helper T cell recognizes complex → Helper T cell secretes cytokines → B cell activation

Question 8

Which of the following best describes the difference between MHC class I and MHC class II molecules?

Accepted Answer

MHC I presents endogenous antigens to CD8+ T cells; MHC II presents exogenous antigens to CD4+ T cells.

Question 9

A mutation prevents the expression of TAP proteins in a cell. Which immune process would be most directly affected?

Accepted Answer

Presentation of endogenous antigens by MHC I

Question 10

Which of the following is NOT a function of antibodies?

Accepted Answer

Direct lysis of infected cells

Question 11

A patient experiences a severe allergic reaction after exposure to pollen. Which immunoglobulin and immune mechanism are primarily responsible?

Accepted Answer

IgE-mediated degranulation of mast cells

Question 12

Which of the following best explains the concept of clonal selection in B cells?

Accepted Answer

Only B cells with receptors specific to an encountered antigen proliferate and differentiate.

Question 13

Which cytokine is most likely to be released by dendritic cells after phagocytosing a pathogen, and what is its primary function?

Accepted Answer

Interleukin; acts as a chemical messenger to activate other immune cells

Question 14

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

Accepted Answer

They provide a faster and stronger response upon second exposure to the same antigen.

Question 15

Which of the following scenarios best illustrates the principle of passive immunity?

Accepted Answer

A child receives IgG antibodies from the mother through the placenta.

Question 16

Which immune cell is responsible for killing virally infected cells by recognizing MHC I-antigen complexes and releasing perforin and granzymes?

Accepted Answer

Cytotoxic T cell (CD8+)

Question 17

Which of the following is a key difference between natural killer (NK) cells and cytotoxic T (TC) cells?

Accepted Answer

TC cells are activated by specific antigen-MHC I complexes, while NK cells kill cells lacking MHC I.

Question 18

Which antibody class is most abundant in body secretions and plays a critical role in mucosal immunity?

Accepted Answer

IgA

Question 19

A patient is exposed to the same pathogen for a second time. Which of the following best describes the expected antibody response?

Accepted Answer

A faster and stronger IgG response due to memory cells

Adaptive Immunity: Structure, Function, and Mechanisms

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