Question 1

Which of the following best describes the primary difference between innate and adaptive immunity?

Accepted Answer

Innate immunity provides a rapid, non-specific response, while adaptive immunity provides a slower, highly specific response.

Question 2

A patient receives a vaccine containing an inactivated virus. Which sequence best describes the immune response leading to long-term protection?

Accepted Answer

The vaccine stimulates B cells to produce antibodies, and some B cells differentiate into memory B cells for future responses.

Question 3

Which cell type is primarily responsible for presenting antigens to helper T cells via MHC class II molecules?

Accepted Answer

Antigen-presenting cells such as dendritic cells and macrophages

Question 4

CAR T cell therapy is a promising cancer treatment. Which statement best explains how CAR T cells differ from normal cytotoxic T cells in targeting cancer?

Accepted Answer

CAR T cells recognize cancer cells using engineered receptors that bind directly to tumor antigens, bypassing the need for antigen presentation by MHC molecules.

Question 5

Which of the following best describes clonal selection in the adaptive immune response?

Accepted Answer

The proliferation of B or T cells that have bound to a specific antigen, resulting in a population of identical cells.

Question 6

A person is exposed to a novel pathogen. Which sequence correctly describes the initial steps of the innate immune response?

Accepted Answer

Phagocytic cells such as macrophages and neutrophils recognize pathogen-associated molecular patterns using toll-like receptors and engulf the pathogen.

Question 7

Which of the following is a mechanism by which the immune system avoids attacking normal body tissues?

Accepted Answer

Destruction or inactivation of self-reactive lymphocytes during development (central tolerance).

Question 8

Which scenario best illustrates how an autoimmune disease might develop?

Accepted Answer

A B cell that reacts to a self-antigen escapes deletion and produces antibodies against the body's own tissues.

Question 9

Which of the following best explains why memory B cells are important for long-term immunity?

Accepted Answer

They rapidly proliferate and differentiate into plasma cells upon re-exposure to the same antigen, producing a faster and stronger antibody response.

Question 10

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

Accepted Answer

Recognition and killing of infected cells by cytotoxic T cells.

Question 11

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

Accepted Answer

They activate B cells and cytotoxic T cells by releasing cytokines after recognizing antigens presented by MHC class II molecules.

Question 12

Which of the following is an example of a humoral immune response?

Accepted Answer

B cells differentiating into plasma cells that secrete antibodies into the bloodstream.

Question 13

Which of the following best explains why vaccines are effective at preventing infectious diseases?

Accepted Answer

They stimulate the production of memory B cells and antibodies specific to the pathogen's antigens.

Question 14

Which of the following is a function of toll-like receptors in the innate immune system?

Accepted Answer

They recognize conserved molecular patterns on pathogens and activate immune responses.

Question 15

A patient receives a bone marrow transplant and later develops an autoimmune disease. Which mechanism could explain this outcome?

Accepted Answer

The transplanted bone marrow contains self-reactive lymphocytes that were not eliminated during development.

Question 16

Which of the following best describes the process of phagocytosis?

Accepted Answer

The engulfment and digestion of pathogens by cells such as macrophages and neutrophils.

Question 17

Which of the following scenarios best illustrates cross-reactivity leading to autoimmunity?

Accepted Answer

A B cell produces antibodies that bind to both a bacterial antigen and a structurally similar self-antigen, leading to tissue damage.

Question 18

Which of the following best explains why cytotoxic T cells are effective against intracellular pathogens?

Accepted Answer

They recognize and kill infected cells displaying pathogen-derived peptides on MHC class I molecules.

Question 19

A patient is infected with a bacterium that remains outside host cells. Which immune response is most important for clearing this infection?

Accepted Answer

Humoral immune response involving B cells and antibodies.

Question 20

Which of the following best describes the role of plasma cells in the immune response?

Accepted Answer

They are differentiated B cells that secrete large quantities of antibodies specific to an antigen.

The Immune System: Innate and Adaptive Immunity, CAR T Cells, Vaccines, and Autoimmunity

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