Question 1

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

Accepted Answer

Innate immunity is present at birth and responds rapidly, while adaptive immunity develops over time and is specific to particular antigens.

Question 2

Which cell type is primarily responsible for antibody production in the adaptive immune response?

Accepted Answer

B cells

Question 3

A patient presents with a severe allergic reaction. Which myeloid cell is most likely responsible for releasing histamine and mediating this response?

Accepted Answer

Mast cells

Question 4

Which of the following best defines a cytokine?

Accepted Answer

A signaling molecule produced by immune cells that regulates immune responses.

Question 5

The skin and mucous membranes contribute to innate immunity primarily by:

Accepted Answer

Acting as physical and chemical barriers to prevent pathogen entry.

Question 6

During phagocytosis, pattern recognition receptors (PRRs) play a critical role by:

Accepted Answer

Recognizing conserved microbial structures and promoting adherence to pathogens.

Question 7

Leishmania donovani is able to evade phagocytosis by:

Accepted Answer

Inhibiting fusion of the phagosome with the lysosome.

Question 8

Which of the following statements about the classical and alternative pathways of complement activation is correct?

Accepted Answer

The classical pathway is triggered by antigen-antibody complexes, while the alternative pathway is activated directly by pathogen surfaces.

Question 9

Which of the following is NOT a function of the complement system?

Accepted Answer

Genetic recombination

Question 10

A patient with a viral infection develops a fever. Which innate defense mechanism is primarily responsible for this response?

Accepted Answer

Fever

Question 11

A 'cytokine storm' is characterized by excessive production of which of the following cytokines?

Accepted Answer

Tumor necrosis factor-alpha (TNF-\alpha), Interleukin-6 (IL-6), and Interleukin-1 (IL-1)

Question 12

Which lymphoid organ is the primary site for maturation of T cells?

Accepted Answer

Thymus

Question 13

In the structure of an antibody, which region is responsible for antigen binding?

Accepted Answer

Variable region

Question 14

Genetic recombination in B cells is essential for antibody diversity. Which process is directly involved in this recombination?

Accepted Answer

V(D)J recombination

Question 15

Which class of antibody is most abundant in serum and is responsible for secondary immune responses?

Accepted Answer

IgG

Question 16

Which function of antibodies involves the binding of pathogens to prevent their attachment to host cells?

Accepted Answer

Neutralization

Question 17

Which statement correctly differentiates MHC I and MHC II molecules?

Accepted Answer

MHC I is found on all nucleated cells and presents endogenous antigens to cytotoxic T cells, while MHC II is found on antigen-presenting cells and presents exogenous antigens to helper T cells.

Question 18

Which cell surface marker is characteristic of T helper cells?

Accepted Answer

CD4

Question 19

The immunological synapse refers to:

Accepted Answer

The interface between a T cell and an antigen-presenting cell involving MHC and T cell receptor interactions.

Question 20

Trypanosoma brucei is able to evade the antibody-mediated response by:

Accepted Answer

Undergoing antigenic variation of its surface glycoproteins.

Study Guide: Host Defenses and Immunity in Microbiology

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