Q: Which equation best represents the noncovalent interaction between a peptide and an MHC molecule during antigen presentation?

$$\text{Peptide} + \text{MHC} \rightarrow \text{Peptide-MHC complex}$$

Q: Which equation best represents the process of antigen presentation by MHC class II molecules?

$$\text{Exogenous antigen} \xrightarrow{APC} \text{MHC II-antigen complex} \xrightarrow{CD4^+ \text{T cell}} \text{T cell activation}$$

Question 1

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

Accepted Answer

They process and present antigens to T cells, initiating adaptive immune responses.

Question 2

A patient is diagnosed with a deficiency in TAP (Transporter associated with antigen processing). Which immune function is most likely impaired?

Accepted Answer

Presentation of endogenous antigens on MHC class I molecules.

Question 3

Which equation best represents the noncovalent interaction between a peptide and an MHC molecule during antigen presentation?

Accepted Answer

$$	ext{Peptide} + 	ext{MHC} ightarrow 	ext{Peptide-MHC complex}$$

Question 4

A viral protein is degraded by the proteasome in a host cell. Which pathway will most likely present the resulting peptides to T cells?

Accepted Answer

MHC class I pathway, presenting to CD8+ T cells.

Question 5

Which of the following statements about MHC molecules is correct?

Accepted Answer

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

Question 6

During antigen presentation, which molecule prevents premature peptide binding to MHC class II in the endoplasmic reticulum?

Accepted Answer

Invariant chain

Question 7

A mutation in the anchor residues of a peptide would most likely affect which aspect of antigen presentation?

Accepted Answer

The stability of the peptide-MHC complex.

Question 8

Which of the following best explains the process of cross-presentation?

Accepted Answer

Dendritic cells present extracellular antigens on MHC class I molecules to CD8+ T cells.

Question 9

Which cell type is capable of both producing antibodies and presenting antigens to helper T cells?

Accepted Answer

B lymphocytes

Question 10

A patient with a defect in HLA-DM would most likely have impaired:

Accepted Answer

Exchange of CLIP for antigenic peptides in MHC class II molecules.

Question 11

Which equation best represents the process of antigen presentation by MHC class II molecules?

Accepted Answer

$$	ext{Exogenous antigen} \xrightarrow{APC} 	ext{MHC II-antigen complex} \xrightarrow{CD4^+ 	ext{T cell}} 	ext{T cell activation}$$

Question 12

Which of the following is a direct consequence of adaptive immunity?

Accepted Answer

Long-lasting protection through memory cells.

Question 13

CD4 and CD8 are co-receptors that recognize antigens presented by which MHC classes, respectively?

Accepted Answer

CD4 recognizes MHC class II; CD8 recognizes MHC class I.

Question 14

Which scenario best illustrates the function of the proteasome in antigen processing?

Accepted Answer

A viral protein is degraded into peptides for loading onto MHC class I.

Question 15

Which of the following steps occurs FIRST in the MHC class I antigen presentation pathway?

Accepted Answer

Proteins are degraded by the proteasome.

Question 16

A cell infected with an intracellular bacterium presents antigens to cytotoxic T cells. Which equation best represents this process?

Accepted Answer

$$	ext{Endogenous antigen} \xrightarrow{Proteasome} 	ext{Peptide} \xrightarrow{TAP} 	ext{MHC I-peptide complex} \xrightarrow{CD8^+ 	ext{T cell}} 	ext{T cell activation}$$

Question 17

Which of the following is TRUE regarding antigen presentation by B lymphocytes?

Accepted Answer

B lymphocytes present antigens to helper T cells via MHC class II molecules.

Question 18

Which process is facilitated by HLA-DM in antigen presentation?

Accepted Answer

Exchange of CLIP for antigenic peptides in MHC class II molecules.

Question 19

A dendritic cell presents a viral antigen on MHC class I to a CD8+ T cell. Which process is this an example of?

Accepted Answer

Cross-presentation

Question 20

Which of the following is a function of anchor residues in antigen presentation?

Accepted Answer

They stabilize the peptide-MHC complex by binding to pockets in the MHC molecule.

Adaptive Immunity and Antigen Presentation: Key Concepts in Immunology

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