$$\text{Target cell} + \text{Perforin} + \text{Granzymes} \rightarrow \text{Apoptosis}$$

Question 1

Which of the following best describes the primary function of dendritic cells (DCs) in the immune response?

Accepted Answer

They engulf and degrade microbes, then display antigens to T cells.

Question 2

Which class of T cells is responsible for recognizing antigens presented by MHC class II molecules on antigen-presenting cells (APCs)?

Accepted Answer

Helper T cells (CD4+)

Question 3

A patient receives an injection of antibodies after exposure to rabies. Which type of adaptive immunity is this an example of?

Accepted Answer

Artificially acquired passive immunity

Question 4

Which of the following is a key difference between the primary and secondary immune responses to an antigen?

Accepted Answer

The secondary response is faster and produces more IgG antibodies.

Question 5

Which equation best represents the process of apoptosis induced by cytotoxic T lymphocytes (CTLs)?

Accepted Answer

$$	ext{Target cell} + 	ext{Perforin} + 	ext{Granzymes} ightarrow 	ext{Apoptosis}$$

Question 6

Which of the following best explains why natural killer (NK) cells can destroy virus-infected cells that lack MHC class I molecules?

Accepted Answer

NK cells detect the absence of MHC class I molecules and induce apoptosis.

Question 7

Which subset of T helper cells is primarily responsible for activating macrophages and is associated with delayed hypersensitivity reactions?

Accepted Answer

T	extsubscript{H}1 cells

Question 8

A protozoan parasite is too large to be phagocytosed. Which immune mechanism is most likely to eliminate it?

Accepted Answer

Antibody-dependent cell-mediated cytotoxicity (ADCC)

Question 9

Which of the following best describes the role of regulatory T cells (Treg) in the immune system?

Accepted Answer

They suppress T cell responses to prevent autoimmunity.

Question 10

Which of the following is a correct sequence of events in the activation of a CD4+ T helper cell?

Accepted Answer

Antigen presentation by MHC II → TCR binding → Costimulatory signal → Cytokine production

Question 11

Which of the following best explains why memory cells are important for the secondary immune response?

Accepted Answer

They allow for a faster and more robust response upon re-exposure to the antigen.

Question 12

Which of the following cell types is NOT considered a professional antigen-presenting cell (APC)?

Accepted Answer

Cytotoxic T lymphocyte

Question 13

Which of the following best describes the process of class switching during a secondary immune response?

Accepted Answer

B cells switch from producing IgM to producing IgG antibodies.

Question 14

Which of the following equations best represents the relationship between antigen exposure and antibody titer in the secondary immune response?

Accepted Answer

$$	ext{Antigen exposure}_{2} ightarrow 	ext{Memory cell activation} ightarrow 	ext{Increased antibody titer}$$

Question 15

Which of the following is a characteristic of artificially acquired active immunity?

Accepted Answer

It results from vaccination.

Question 16

Which of the following best describes the role of perforin in the immune response?

Accepted Answer

It forms pores in the target cell membrane, facilitating entry of granzymes.

Question 17

A newborn receives antibodies from its mother through breast milk. This is an example of which type of immunity?

Accepted Answer

Naturally acquired passive immunity

Question 18

Which of the following best explains why cytotoxic T lymphocytes (CTLs) are effective against intracellular pathogens such as viruses?

Accepted Answer

CTLs recognize viral peptides presented by MHC class I molecules on infected cells.

Question 19

Which of the following is a function of T	extsubscript{H}2 cells?

Accepted Answer

Activate B cells to produce IgE and activate eosinophils.

(Chapter 17, Part 2) Cell-Mediated Immunity and Adaptive Immune Responses

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