$$\text{Activated T cell} \xrightarrow{\text{mitosis}} \text{Clone of identical T cells}$$

Question 1

Which of the following best describes the process of antigen presentation by antigen-presenting cells (APCs)?

Accepted Answer

APCs internalize antigens, digest them into fragments, and display these fragments in the grooves of MHC proteins on their surface.

Question 2

Which type of T cell is primarily responsible for directly attacking and destroying virus-infected or cancerous cells?

Accepted Answer

Cytotoxic T (TC) cells

Question 3

A patient is exposed to a superantigen produced by pathogenic staphylococci. What is the most likely consequence of this exposure?

Accepted Answer

A massive, non-specific activation of T cells leading to excessive cytokine release and potential toxic shock.

Question 4

Which of the following statements about MHC proteins is correct?

Accepted Answer

MHC-1 proteins are found on all nucleated cells and present internal peptides.

Question 5

During T cell activation, what is the role of costimulation?

Accepted Answer

It ensures that T cells are only activated in the presence of both antigen and additional danger signals, preventing autoimmunity.

Question 6

Which of the following best explains why memory T cells respond more rapidly upon re-exposure to the same antigen?

Accepted Answer

They require fewer steps to be activated and are more numerous than naive T cells.

Question 7

A researcher observes that a certain T cell only responds to antigens presented by MHC-2 proteins. Which type of T cell is this most likely to be?

Accepted Answer

Helper T (TH) cell

Question 8

Which of the following is NOT a function of helper T (TH) cells during the attack phase of cellular immunity?

Accepted Answer

Directly killing infected cells by releasing perforin and granzymes.

Question 9

Which equation best represents the process of clonal selection during T cell activation?

Accepted Answer

$$	ext{Activated T cell} \xrightarrow{	ext{mitosis}} 	ext{Clone of identical T cells}$$

Question 10

A patient with a genetic defect in MHC-1 expression would most likely have impaired function in which immune process?

Accepted Answer

Destruction of virus-infected and cancerous cells by cytotoxic T cells.

Question 11

Which of the following best describes the role of regulatory T (TR) cells?

Accepted Answer

They suppress pathological immune responses and help maintain immune tolerance.

Question 12

Which of the following scenarios best illustrates the concept of MHC restriction?

Accepted Answer

Cytotoxic T cells only respond to antigens presented by MHC-1 proteins, while helper T cells only respond to antigens presented by MHC-2 proteins.

Question 13

Which of the following is a direct effect of interleukins secreted by helper T cells?

Accepted Answer

Attraction of neutrophils and NK cells to the site of infection.

Question 14

A patient is unable to mount a rapid immune response upon re-exposure to a pathogen. Which cell type is most likely deficient?

Accepted Answer

Memory T cells

Question 15

Which of the following best explains why identical twins have structurally identical MHC proteins?

Accepted Answer

They have identical genetic material encoding the MHC complex.

Question 16

Which of the following is a correct sequence of events in the activation of a cytotoxic T cell?

Accepted Answer

Antigen recognition → Costimulation → Clonal selection → Attack

Question 17

Which chemical released by cytotoxic T cells is responsible for creating pores in the membrane of target cells?

Accepted Answer

Perforin

Question 18

A patient with a deficiency in helper T cells would most likely experience which of the following?

Accepted Answer

Impaired coordination of both cellular and humoral immune responses.

Question 19

Which of the following best describes the function of memory in cellular immunity?

Accepted Answer

It allows for a faster and stronger response upon subsequent exposures to the same antigen.

Question 20

Which of the following is a real-world example of the importance of cytotoxic T cells in human health?

Accepted Answer

Destruction of cancer cells by recognizing tumor antigens presented on MHC-1 proteins.

Cellular Immunity: T Cells, Antigen Presentation, and Immune Response

Study Guide - Practice Questions