Question 1

Which of the following best describes the primary difference between humoral and cellular immunity?

Accepted Answer

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

Question 2

A patient receives an injection of preformed antibodies after exposure to rabies. Which type of adaptive immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 3

Which immunoglobulin class is most abundant in serum and can cross the placenta to protect the fetus?

Accepted Answer

IgG

Question 4

What is the role of the variable (V) region of an antibody molecule?

Accepted Answer

It binds specifically to epitopes on antigens.

Question 5

Which of the following best explains why haptens alone do not elicit an immune response?

Accepted Answer

They are too small to be recognized as antigens unless attached to a carrier molecule.

Question 6

A child is exposed to chickenpox and develops immunity after recovering. Which type of immunity is this?

Accepted Answer

Naturally acquired active immunity

Question 7

Which process describes the elimination of B cells that may react against self-antigens during development?

Accepted Answer

Clonal deletion

Question 8

Which of the following is a function of TH1 cells?

Accepted Answer

Produce IFN-γ to activate macrophages and enhance phagocytosis

Question 9

Which of the following best describes the mechanism of action for cytotoxic T lymphocytes (CTLs)?

Accepted Answer

They release perforin and granzymes to induce apoptosis in infected cells presenting antigen with MHC class I.

Question 10

Which immunoglobulin class is primarily found in secretions such as saliva, tears, and breast milk, and helps prevent microbial attachment to mucous membranes?

Accepted Answer

IgA

Question 11

A laboratory test measures the antibody titer in a patient's serum. What does a high antibody titer indicate?

Accepted Answer

The patient has a strong humoral immune response, possibly due to recent or past exposure to an antigen.

Question 12

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

Accepted Answer

They stimulate B cells directly, usually producing IgM and no memory cells.

Question 13

Which of the following best describes the role of natural killer (NK) cells in the adaptive immune system?

Accepted Answer

They destroy cells that do not express MHC class I self-antigens, including virus-infected and tumor cells.

Question 14

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

Accepted Answer

Direct lysis of viruses by antibodies alone

Question 15

Which cytokine is primarily responsible for inducing inflammation by recruiting neutrophils and is produced by TH17 cells?

Accepted Answer

IL-17

Question 16

A newborn receives antibodies from its mother through breast milk. Which type of immunity is this?

Accepted Answer

Naturally acquired passive immunity

Question 17

Which of the following best explains the concept of 'class switching' in immunological memory?

Accepted Answer

The immune system switches from producing IgM to IgG, IgE, or IgA during a secondary response.

Question 18

Which of the following is a function of regulatory T cells (Treg)?

Accepted Answer

Suppress T cells against self-antigens and protect beneficial intestinal bacteria

Question 19

Which of the following best describes the role of antigen-presenting cells (APCs) in adaptive immunity?

Accepted Answer

They engulf and degrade microbes, then display antigen fragments on MHC molecules to T cells.

Question 20

Which of the following is a possible consequence of cytokine overproduction?

Accepted Answer

Cytokine storm, leading to excessive inflammation and tissue damage

Adaptive Immunity: Specific Defenses of the Host – Study Notes

Study Guide - Practice Questions

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