Question 1

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

Accepted Answer

To display peptide fragments of protein antigens in association with MHC molecules for recognition by T cells

Question 2

Which of the following cell types is NOT considered a professional antigen presenting cell (APC)?

Accepted Answer

Neutrophil

Question 3

A viral protein is synthesized in the cytosol of a nucleated cell. Through which pathway will this antigen most likely be processed and presented?

Accepted Answer

Class I MHC pathway, presented to CD8+ T cells

Question 4

Which of the following statements about MHC genes is CORRECT?

Accepted Answer

MHC genes are highly polymorphic and co-dominantly expressed

Question 5

Which of the following best explains why MHC molecules display only one peptide at a time?

Accepted Answer

The peptide-binding groove is highly specific and can accommodate only one peptide due to anchor residues

Question 6

Which of the following is a key difference between MHC class I and class II molecules?

Accepted Answer

Class I MHC molecules are expressed on all nucleated cells, while class II MHC molecules are mainly on dendritic cells, macrophages, and B lymphocytes

Question 7

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

Accepted Answer

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

Question 8

Which of the following is TRUE regarding the binding of peptides to MHC molecules?

Accepted Answer

Anchor residues of the peptide fit into pockets of the MHC molecule

Question 9

A patient receives a kidney transplant from a genetically unrelated donor. Which property of MHC molecules is most relevant to the likelihood of transplant rejection?

Accepted Answer

MHC molecules are highly polymorphic, leading to differences between individuals

Question 10

Which of the following steps is unique to the processing of antigens for presentation by class II MHC molecules?

Accepted Answer

Association of processed peptides with class II MHC molecules in endosomal/lysosomal vesicles

Question 11

Which of the following best describes the role of the invariant chain (Ii) in MHC class II antigen processing?

Accepted Answer

It prevents premature binding of peptides to class II MHC molecules in the ER

Question 12

Which of the following is a consequence of the co-dominant expression of MHC genes?

Accepted Answer

Both maternal and paternal alleles of each MHC gene are expressed, increasing the diversity of peptides presented

Question 13

Which of the following best explains why T cells are said to be 'MHC restricted'?

Accepted Answer

A single T cell can recognize only a specific peptide presented on a specific MHC molecule

Question 14

Which of the following is a feature of peptide-MHC interactions that enhances immune specificity?

Accepted Answer

Each MHC molecule displays only one peptide at a time, ensuring precise T cell recognition

Question 15

Which of the following best describes the role of HLA-DM in antigen processing?

Accepted Answer

It acts as a peptide exchanger, removing CLIP and facilitating peptide binding to class II MHC molecules

Question 16

A mutation in the TAP gene would most directly impair which aspect of antigen presentation?

Accepted Answer

Transport of peptides from the cytosol to the endoplasmic reticulum for class I MHC loading

Question 17

Which of the following best explains why class II MHC molecules are primarily expressed on dendritic cells, macrophages, and B lymphocytes?

Accepted Answer

These cells are specialized for capturing and presenting extracellular antigens to CD4+ T cells

Question 18

Which of the following is a direct result of antigen presentation by class II MHC molecules on dendritic cells?

Accepted Answer

Activation of naïve CD4+ T cells

Question 19

Which of the following best describes the role of proteasomes in antigen processing?

Accepted Answer

They degrade cytosolic proteins into peptides for class I MHC presentation

Antigen Capture and Presentation: Foundations of Immunology

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