Question 1

Which of the following best describes the primary difference between humoral and cellular immunity in the adaptive immune system?

Accepted Answer

Humoral immunity produces antibodies to combat antigens outside cells, while cellular immunity uses T cells to target infected or abnormal cells.

Question 2

A patient receives an injection of antibodies after being exposed to rabies. What type of adaptive immunity is this an example of?

Accepted Answer

Artificially acquired passive immunity

Question 3

Which immunoglobulin class is most abundant in serum and is capable of crossing the placenta to protect the fetus?

Accepted Answer

IgG

Question 4

A laboratory test detects a high concentration of IgM in a patient's serum. What does this most likely indicate?

Accepted Answer

The patient is in the early stages of a primary immune response.

Question 5

Which of the following best explains why a person who has recovered from measles is usually immune to future infections by the same virus?

Accepted Answer

Memory cells produced during the primary response enable a faster and stronger secondary response.

Question 6

Which of the following is a function of cytokines known as chemokines?

Accepted Answer

They induce migration (chemotaxis) of leukocytes to sites of infection.

Question 7

A small molecule that is not antigenic by itself but can elicit an immune response when attached to a carrier protein is called a:

Accepted Answer

Hapten

Question 8

Which process describes the elimination of self-reactive B cells during immune system development?

Accepted Answer

Clonal deletion

Question 9

Which of the following is a correct sequence of events in the activation of B cells by T-dependent antigens?

Accepted Answer

Antigen binds BCR → B cell internalizes antigen → Antigen presented on MHC II → T helper cell recognizes antigen → B cell activation

Question 10

Which of the following best describes the role of MHC class I molecules?

Accepted Answer

They present endogenous antigens to cytotoxic T lymphocytes (CTLs).

Question 11

A patient with a parasitic worm infection is likely to have elevated levels of which immunoglobulin?

Accepted Answer

IgE

Question 12

Which of the following is NOT a result of antigen-antibody binding?

Accepted Answer

Antigen presentation on MHC I

Question 13

Which cell type is responsible for killing virus-infected cells by releasing perforin and granzymes, leading to apoptosis?

Accepted Answer

Cytotoxic T lymphocytes (CD8+)

Question 14

Which of the following best explains why natural killer (NK) cells can destroy some virus-infected or tumor cells that cytotoxic T cells cannot?

Accepted Answer

NK cells recognize cells lacking MHC class I molecules, while cytotoxic T cells require antigen presentation on MHC I.

Question 15

Which immunoglobulin class is most important in preventing microbial attachment to mucous membranes and is found in secretions such as saliva and breast milk?

Accepted Answer

IgA

Question 16

A child is exposed to chickenpox and develops the disease, later becoming immune. Which type of adaptive immunity is this?

Accepted Answer

Naturally acquired active immunity

Question 17

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, IgA, or IgE antibodies.

Question 18

Which of the following is a correct statement about T-independent antigens?

Accepted Answer

They are often polysaccharides from bacterial capsules or LPS.

Question 19

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

Accepted Answer

They suppress immune responses against self-antigens and help maintain tolerance.

Question 20

Which of the following is a possible consequence of an overproduction of cytokines?

Accepted Answer

Cytokine storm, leading to excessive inflammation and tissue damage

Adaptive Immunity: Specific Defenses of the Host (Chapter 17 Study Notes)

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