Question 1

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

Accepted Answer

Innate immunity is inherited and nonspecific, while adaptive immunity is induced and specific to microbial invaders.

Question 2

A patient receives an injection of antibodies after exposure to rabies. Which type of immunity is this, and why is it considered short-lived?

Accepted Answer

Passive artificial immunity; because the injected antibodies have a short half-life and no memory cells are produced.

Question 3

Which immunoglobulin class is primarily responsible for protecting mucosal surfaces and is found in secretions such as saliva, tears, and breast milk?

Accepted Answer

IgA

Question 4

A newborn is protected from certain infections due to antibodies received from the mother through the placenta. Which immunoglobulin is responsible for this protection?

Accepted Answer

IgG

Question 5

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

Accepted Answer

Memory cells generated during the primary response quickly recognize and respond to the antigen.

Question 6

Which of the following is NOT a function of antibodies in the immune response?

Accepted Answer

Direct lysis of pathogens by forming pores

Question 7

A patient with a parasitic worm infection develops an allergic reaction. Which immunoglobulin is most likely elevated in this patient?

Accepted Answer

IgE

Question 8

Which of the following statements about clonal selection is correct?

Accepted Answer

Clonal selection results in the production of plasma cells that secrete antibodies and memory cells.

Question 9

Which type of T cell is primarily responsible for directly killing virus-infected cells and how does it accomplish this?

Accepted Answer

Cytotoxic T cells (CD8+); by releasing perforin and granzymes to induce apoptosis

Question 10

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

Accepted Answer

APCs engulf and degrade microbes, then present antigen fragments on MHC molecules to T cells.

Question 11

A laboratory test separates serum proteins using gel electrophoresis. Which fraction contains the majority of antibodies?

Accepted Answer

Gamma globulin

Question 12

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

Accepted Answer

They are mainly polysaccharides, provoke a weak immune response, and usually produce IgM.

Question 13

Which cytokine is primarily responsible for causing leukocytes to migrate to the site of infection?

Accepted Answer

Chemokine

Question 14

A patient with an autoimmune disease is found to have an overproduction of cytokines, resulting in tissue damage. What is this phenomenon called?

Accepted Answer

Cytokine storm

Question 15

Which of the following best explains why the immune system does not normally attack the body's own cells?

Accepted Answer

Self-antigens are not recognized by B and T cells due to clonal deletion during development.

Question 16

Which immunoglobulin is the first to appear in the primary immune response and is most effective at agglutinating microbes?

Accepted Answer

IgM

Question 17

A patient is exposed to a bacterial toxin and develops antibodies that neutralize the toxin. Which antibody function is being demonstrated?

Accepted Answer

Neutralization

Question 18

Which of the following is TRUE regarding the structure of a typical antibody (immunoglobulin) molecule?

Accepted Answer

It consists of two identical heavy chains and two identical light chains joined by disulfide bonds.

Question 19

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

Accepted Answer

They recognize pathogens from previous encounters and mount a faster, stronger response upon re-exposure.

Question 20

Which of the following is a correct sequence of events in the activation of antibody-producing cells by clonal selection?

Accepted Answer

Antigen binds to B cell receptor → B cell activation → differentiation into plasma cells and memory cells → secretion of antibodies

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

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