Question 1

Which of the following best describes the primary function of cytokines in the immune system?

Accepted Answer

They act as chemical messengers that mediate cell development, differentiation, and immune responses.

Question 2

A patient receives a kidney transplant from a genetically unrelated donor. Which type of graft is this, and what is a major concern post-surgery?

Accepted Answer

Allograft; risk of immune rejection due to MHC mismatch

Question 3

Helper T (T$_H$) cells are essential for which of the following reasons?

Accepted Answer

They activate both humoral and cellular arms of the adaptive immune response.

Question 4

Which cytokine is released by macrophages to stimulate bound T cells, and what is its effect?

Accepted Answer

Interleukin 1 (IL-1); stimulates T cells to release IL-2 and synthesize more IL-2 receptors

Question 5

A patient with severe combined immunodeficiency (SCID) has a genetic defect in the adenosine deaminase (ADA) enzyme. What is the consequence of this defect?

Accepted Answer

Accumulation of toxic metabolites that are lethal to T cells, leading to a marked deficit in B and T cells

Question 6

Which of the following best explains why regulatory T (T$_{Reg}$) cells are important in the immune system?

Accepted Answer

They suppress self-reactive lymphocytes and help prevent autoimmune reactions.

Question 7

A patient develops an autoimmune disease after a viral infection. Which mechanism best explains how this could occur?

Accepted Answer

Foreign antigens from the virus resemble self-antigens, leading to cross-reactivity of antibodies.

Question 8

Which of the following is NOT a typical target for cytotoxic T (T$_C$) cells?

Accepted Answer

Extracellular bacteria in the bloodstream

Question 9

A patient is treated with immunosuppressive therapy after an organ transplant. Which of the following is a likely side effect of this treatment?

Accepted Answer

Increased susceptibility to infections

Question 10

Which of the following best describes the process by which cytotoxic T (T$_C$) cells kill their target cells?

Accepted Answer

They release perforin and granzymes, which induce apoptosis in the target cell.

Question 11

Which of the following is a real-world example of an allograft?

Accepted Answer

A liver transplant from one unrelated human to another

Question 12

A patient with AIDS is susceptible to opportunistic infections because:

Accepted Answer

HIV impairs the activity of helper T (T$_H$) cells, crippling the immune response.

Question 13

Which of the following best explains why matching MHC antigens is important in organ transplantation?

Accepted Answer

Mismatched MHC antigens increase the risk of immune rejection of the transplanted organ.

Question 14

Which of the following scenarios could lead to the appearance of new self-antigens and potentially trigger autoimmunity?

Accepted Answer

Gene mutations or trauma that releases novel self-antigens

Question 15

Which of the following is a function of interleukin 2 (IL-2) in the immune response?

Accepted Answer

Stimulates proliferation of T and B cells

Question 16

A patient with type 1 diabetes mellitus is found to have autoantibodies against pancreatic beta cells. This is an example of:

Accepted Answer

An autoimmune disease caused by loss of self-tolerance

Question 17

Which of the following best describes the difference between autografts and xenografts?

Accepted Answer

Autografts are from one body site to another in the same person, while xenografts are from another animal species.

Question 18

Which of the following is a plausible outcome if regulatory T (T$_{Reg}$) cells fail to function properly?

Accepted Answer

Increased risk of developing autoimmune diseases

Question 19

A patient with glomerulonephritis is found to have antibodies that cross-react with kidney tissue after a streptococcal infection. This is an example of which mechanism of autoimmunity?

Accepted Answer

Antibodies against foreign antigen cross-reacting with self-antigen

Question 20

Which of the following best explains why patients with SCID are at high risk for infections?

Accepted Answer

They have a marked deficit in both B and T cells, impairing both humoral and cellular immunity.

Cellular Immunity: T Cells and Immune Regulation (Part 2: Part 2)

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