Question 1

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

Accepted Answer

Humoral immunity involves antibodies produced by B cells, whereas cellular immunity involves direct cell-to-cell interactions by T cells.

Question 2

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

Accepted Answer

Artificially acquired passive immunity

Question 3

Which antibody class is primarily responsible for the initial response to a new infection and is found as a pentamer in the blood?

Accepted Answer

IgM

Question 4

A child is exposed to chickenpox and recovers, developing long-term immunity. What is the best explanation for this?

Accepted Answer

The child developed naturally acquired active immunity by producing their own antibodies and memory cells.

Question 5

Which of the following best describes the function of cytotoxic T cells (CTLs)?

Accepted Answer

They destroy infected or abnormal cells by inducing apoptosis.

Question 6

A laboratory test detects a rapid and high increase in antibody titer within 3 days after a second exposure to an antigen. What is this response called?

Accepted Answer

Secondary immune response

Question 7

Which of the following is true regarding Major Histocompatibility Complex (MHC) molecules?

Accepted Answer

MHC class I molecules are found on all nucleated cells and present antigens to CD8+ T cells.

Question 8

Which of the following best describes the role of cytokines in the immune response?

Accepted Answer

Cytokines are chemical messengers that regulate communication and activity among immune cells.

Question 9

A patient with a genetic defect cannot produce perforin. Which immune function would be most directly impaired?

Accepted Answer

Destruction of infected or abnormal cells by cytotoxic T cells and NK cells

Question 10

Which of the following is a correct statement about haptens?

Accepted Answer

Haptens are low molecular weight compounds that must bind to a carrier to become antigenic.

Question 11

A researcher observes that a certain antigen can stimulate B cells to produce antibodies without the involvement of T cells. This antigen is best described as:

Accepted Answer

A T-independent antigen

Question 12

Which of the following antibody classes is most abundant in blood and is responsible for neutralizing toxins and viruses?

Accepted Answer

IgG

Question 13

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

Accepted Answer

Naturally acquired passive immunity

Question 14

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies coat antigens, enhancing their ingestion and lysis by phagocytes.

Question 15

A patient experiences a severe inflammatory reaction due to excessive cytokine release. This phenomenon is best described as:

Accepted Answer

Cytokine storm

Question 16

Which of the following is a function of helper T cells (TH)?

Accepted Answer

Activate B cells to produce antibodies

Question 17

Which equation correctly represents the 'rule of 8' for MHC and T cell interactions?

Accepted Answer

$$CD4 	imes MHC2 = 8$$

Question 18

During an immune response, which of the following events occurs first in the activation of a CD4+ T cell?

Accepted Answer

An antigen-presenting cell displays an antigen with MHC II on its surface.

Question 19

Which of the following best explains why memory cells are important in adaptive immunity?

Accepted Answer

They allow for a faster and stronger antibody response upon re-exposure to the same antigen.

Question 20

A patient with a deficiency in MHC class II molecules would have the most difficulty with which immune function?

Accepted Answer

Activation of helper T cells and subsequent antibody production

Question 21

Which of the following is a correct sequence of events in the primary immune response?

Accepted Answer

Antigen exposure → slow rise in antibody titer → peak at 10-17 days → memory cell formation

Chapter 17: Adaptive Immunity – Specific Defenses of the Host

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