Question 1

Which of the following best describes the role of helper T (TH) cells in the adaptive immune response?

Accepted Answer

They activate B cells, cytotoxic T cells, and macrophages by releasing cytokines.

Question 2

A patient receives a kidney transplant. Which class of MHC protein on the donor kidney cells is most likely to trigger a cytotoxic T cell response in the recipient?

Accepted Answer

MHC Class I proteins on all nucleated cells

Question 3

Which of the following is required for the activation of a naïve cytotoxic T (TC) cell?

Accepted Answer

Recognition of antigen presented by MHC I and co-stimulation by CD8

Question 4

A B cell is activated when it binds to its specific antigen and receives co-stimulatory signals from a helper T cell. Which cytokines are most important for B cell proliferation and differentiation into plasma cells?

Accepted Answer

Interleukin-2 (IL-2) and Interleukin-6 (IL-6)

Question 5

Which of the following best explains why a secondary immune response is faster and more effective than a primary immune response?

Accepted Answer

Memory B cells and T cells are already present and can rapidly respond to the antigen.

Question 6

Which of the following statements about antigenic determinants (epitopes) is correct?

Accepted Answer

Antigenic determinants are the specific regions of an antigen that antibodies or lymphocyte receptors bind to.

Question 7

A patient with a genetic defect in regulatory T cells (Tregs) is most likely to develop which of the following conditions?

Accepted Answer

Autoimmune diseases due to loss of self-tolerance

Question 8

Which of the following is a function of antibodies in the immune response?

Accepted Answer

Tagging antigens for destruction by other immune cells (opsonization)

Question 9

Which of the following best describes the process of antigen presentation by MHC Class II molecules?

Accepted Answer

MHC II molecules present exogenous antigens to helper T cells.

Question 10

A patient is exposed to a virus for the first time. Which of the following best describes the timeline and characteristics of the primary immune response?

Accepted Answer

There is a lag period of 4-5 days, with peak antibody levels at about 10 days, followed by a decline.

Question 11

Which of the following is a key difference between MHC Class I and MHC Class II molecules?

Accepted Answer

MHC Class I molecules present endogenous antigens to CD8+ T cells, while MHC Class II molecules present exogenous antigens to CD4+ T cells.

Question 12

A patient with AIDS is most likely to have a deficiency in which of the following cell types?

Accepted Answer

Helper T cells (CD4+)

Question 13

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

Accepted Answer

Only lymphocytes with receptors specific to the presented antigen are activated to proliferate and differentiate.

Question 14

Which of the following cytokines is primarily responsible for stimulating the proliferation of helper T cells and acting as a pyrogen to induce fever?

Accepted Answer

Interleukin-1 (IL-1)

Question 15

A patient is stung by a bee and develops an immediate, systemic allergic reaction. Which immunoglobulin and immune mechanism are primarily responsible for this response?

Accepted Answer

IgE and mast cell degranulation

Question 16

Which of the following best explains why complex molecules such as proteins and polysaccharides are more immunogenic than simple molecules like plastics?

Accepted Answer

Complex molecules have more antigenic determinants (epitopes) that can be recognized by the immune system.

Question 17

Which of the following is a direct result of the release of perforins and granzymes by cytotoxic T cells?

Accepted Answer

Induction of apoptosis in infected or abnormal cells

Question 18

A patient with a history of repeated infections is found to have a genetic defect affecting both T and B lymphocytes. Which immunodeficiency is most likely?

Accepted Answer

Severe combined immunodeficiency (SCID)

Question 19

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies bind to antigens, making them easier for phagocytes to recognize and engulf.

Adaptive Immunity: Specific Defense System in Human Physiology

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