Q: Which equation best represents the clonal expansion of lymphocytes after activation?

$$N_{final} = N_{initial} \times 2^n$$

Q: Which equation represents the relationship between antibody concentration and time after secondary antigen exposure?

$$A(t) = A_0$ \times e$$^{kt}$$

Question 1

Which of the following best describes the role of MHC I molecules in the adaptive immune response?

Accepted Answer

MHC I molecules present intracellular antigens to CD8+ T cytotoxic cells.

Question 2

A patient is exposed to a viral infection. Which immune cell is primarily responsible for directly killing infected host cells, and what molecule does it use to recognize these cells?

Accepted Answer

CD8+ T cytotoxic cell; recognizes infected cells using MHC I.

Question 3

Which equation best represents the clonal expansion of lymphocytes after activation?

Accepted Answer

$$N_{final} = N_{initial} 	imes 2^n$$

Question 4

Which antibody isotype is most abundant in human blood and is capable of crossing the placenta?

Accepted Answer

IgG

Question 5

During a secondary antigen exposure, which of the following best describes the antibody response compared to primary exposure?

Accepted Answer

The antibody titer is higher and faster.

Question 6

Which of the following is a function of TH1 cells in the adaptive immune response?

Accepted Answer

Activate cytotoxic T cells, macrophages, and natural killer cells.

Question 7

A patient with a deficiency in CD40L would most likely have impaired activation of which cell type?

Accepted Answer

B cells by T-dependent antigens

Question 8

Which of the following best explains why B cells can recognize antigens without the need for antigen-presenting cells (APCs)?

Accepted Answer

B cell receptors (BCRs) can directly bind to soluble antigens.

Question 9

Which antibody isotype is most prevalent in mucosal secretions and can exist as a dimer?

Accepted Answer

IgA

Question 10

Which of the following is a correct sequence of the four stages of the adaptive immune response?

Accepted Answer

Antigen presentation → Lymphocyte activation → Lymphocyte proliferation and differentiation → Antigen elimination and memory

Question 11

Which of the following best describes the function of perforins and granzymes released by cytotoxic T cells?

Accepted Answer

Perforins form pores in target cells, and granzymes induce apoptosis.

Question 12

Which equation represents the relationship between antibody concentration and time after secondary antigen exposure?

Accepted Answer

$$A(t) = A_0$ 	imes e$$^{kt}$$

Question 13

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

Accepted Answer

Direct destruction of virus-infected cells

Question 14

A patient is found to have high levels of IgE. Which condition is most likely associated with this finding?

Accepted Answer

Allergic response or parasitic infection

Question 15

Which of the following best describes the process of isotype switching in B cells?

Accepted Answer

B cells alter the class of antibody they produce while maintaining epitope specificity.

Question 16

Which of the following is a key difference between T-independent and T-dependent antigen activation of B cells?

Accepted Answer

T-dependent antigens require T helper cells and co-stimulatory signals for activation.

Question 17

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

Accepted Answer

They allow for a rapid and amplified response upon re-exposure to the same antigen.

Question 18

Which of the following is true regarding the location and function of MHC II molecules?

Accepted Answer

MHC II molecules are found only on antigen-presenting cells and present extracellular antigens.

Question 19

Which of the following best describes the role of regulatory T cells (Treg) in the immune response?

Accepted Answer

They decrease immune responses once the threat has passed.

Adaptive Immunity: T Cells, B Cells, and Antibody-Mediated Responses

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