Question 1

Which of the following best describes the main difference between the primary and secondary adaptive immune responses, as shown in the antibody titer graph?

Accepted Answer

The secondary response is faster and produces a higher concentration of IgG antibodies due to immunological memory.

Question 2

Which of the following is TRUE regarding antigen presentation in the adaptive immune response?

Accepted Answer

Antigen-presenting cells (APCs) use MHC II to present extracellular antigens to T helper cells.

Question 3

A patient receives antibodies from an antivenom after a snake bite. Which type of immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 4

Which of the following best explains why proteins are generally more immunogenic than lipids?

Accepted Answer

Proteins have greater molecular complexity and size, increasing their ability to trigger an immune response.

Question 5

What is the role of T helper 2 (TH2) cells in the adaptive immune response?

Accepted Answer

They stimulate B cells to produce antibodies, promoting the humoral response.

Question 6

Which of the following events occurs during Stage 3 of the adaptive immune response?

Accepted Answer

Lymphocyte proliferation and differentiation into effector and memory cells

Question 7

A patient is exposed to a virus for the first time. Which antibody is produced first in the primary immune response?

Accepted Answer

IgM

Question 8

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

Accepted Answer

They remain in lymphatic tissues and enable a rapid, amplified response upon re-exposure to the same antigen.

Question 9

Which of the following is a correct statement about the interaction between T cells and MHC molecules?

Accepted Answer

T cytotoxic cells recognize antigens presented by MHC I, while T helper cells recognize antigens presented by MHC II.

Question 10

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies tag antigens, enhancing their recognition and uptake by phagocytes.

Question 11

Which of the following is a feature of T-independent antigens?

Accepted Answer

They can directly activate B cells by cross-linking multiple B cell receptors.

Question 12

Which antibody isotype is most prevalent in mucosal secretions such as saliva and tears?

Accepted Answer

IgA

Question 13

A patient with a genetic defect cannot produce MHC I molecules. Which immune function would be most directly impaired?

Accepted Answer

Destruction of virus-infected or cancerous cells by T cytotoxic cells

Question 14

Which of the following best describes the role of perforins and granzymes released by T cytotoxic cells?

Accepted Answer

Perforins form pores in target cell membranes, allowing granzymes to enter and induce apoptosis.

Question 15

Which of the following is a characteristic of haptens?

Accepted Answer

They must be linked to a larger protein or polysaccharide to become immunogenic.

Question 16

Which of the following best explains why tissue transplants are often rejected by the recipient's immune system?

Accepted Answer

The recipient's immune system recognizes foreign MHC molecules on the transplanted tissue.

Question 17

Which of the following is NOT a function of antibodies?

Accepted Answer

Directly killing infected host cells

Question 18

Which of the following best describes the process of clonal expansion?

Accepted Answer

The rapid proliferation of activated lymphocytes to produce effector and memory cells.

Question 19

Which of the following is TRUE about the screening of T and B cells for self-tolerance?

Accepted Answer

Both T and B cells that react strongly to self-antigens are signaled to undergo apoptosis.

Adaptive Immunity: Mechanisms and Features

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