Question 1

How many complementarity-determining regions contribute to the antigen-binding site in an intact T-cell receptor?

Accepted Answer

A) 2 
B) 3 
C) 4 
D) 6 
E) 12.

Question 2

Discuss how T-cell receptors differ from immunoglobulins in the way that they recognize antigen.Use the following terms in your

Accepted Answer

The answer of Discuss how T-cell receptors differ from immunoglobulins...

Question 3

MHC molecules have promiscuous binding specificity.This means that

Accepted Answer

A) a particular MHC molecule has the potential to bind to different peptides 
B) when MHC molecules bind to peptides,they are degraded 
C) peptides bind with low affinity to MHC molecules 
D) none of the above describes promiscuous binding specificity.

Question 4

The complementarity-determining region (CDR)1 and CDR2 loops of the T-cell receptor contact the _______:

Accepted Answer

A) side chains of amino acids in the middle of the peptide 
B) co-receptors CD4 or CD8 
C) membrane-proximal domains of the MHC molecule 
D) constant regions of antibody molecules 
E) α helices of the MHC molecule.

Question 5

T cells recognize antigen when the antigen

Accepted Answer

A) forms a complex with membrane-bound MHC molecules on another host-derived cell 
B) is internalized by T cells via phagocytosis and subsequently binds to T-cell receptors in the endoplasmic reticulum 
C) is presented on the surface of a B cell on membrane-bound immunoglobulins 
D) forms a complex with membrane-bound MHC molecules on the T cell 
E) bears epitopes derived from proteins,carbohydrates,and lipids.

Question 6

The peptide-binding groove of MHC class I molecules is composed of the following extracellular domains:

Accepted Answer

A) α1:β1 
B) β1:β2 
C) α2:β2 
D) α2:α3 
E) α1:α2.

Question 7

A.What are alloantibodies?
B.How do alloantibodies arise naturally?
C.Why are alloantibodies problematic for transplantation?

Accepted Answer

The answer of A.What are alloantibodies?
B.How do alloantibodies arise naturally?
C.Why...

Question 8

Identify the three functions of the invariant chain.

Accepted Answer

The answer of Identify the three functions of the invariant...

Question 9

Which of the following HLA-DRB genotypes is not possible in an individual? (X: X represents diploid genotype.)

Accepted Answer

A) DRB1: DRB1 
B) DRB1,DRB3: DRB1,DRB4 
C) DRB1: DRB1,DRB5 
D) DRB1,DRB4: DRB1 
E) DRB3: DRB1,DRB5.

Question 10

Explain the difference between interallelic conversion and gene conversion,and (B)provide an example for both.

Accepted Answer

The answer of Explain the difference between interallelic conversion and...

Question 11

The diversity of MHC class I and II genes is due to _____.(Select all that apply.)

Accepted Answer

A) gene rearrangements similar to those observed in T-cell receptor genes 
B) the existence of many similar genes encoding MHC molecules in the genome 
C) somatic hypermutation 
D) extensive polymorphism at many of the alleles 
E) isotype switching.

Question 12

What evidence supports the proposal that MHC diversity evolved by natural selection caused by infectious pathogens rather than exclusively by random DNA mutations?

Accepted Answer

The answer of What evidence supports the proposal that MHC...

Question 13

The mechanisms contributing to peptide editing include which of the following? (Select all that apply.)

Accepted Answer

A) removal of amino acids from the amino-terminal end by endoplasmic reticulum aminopeptidase (ERAP) 
B) cathepsin S-mediated cleavage of invariant chain 
C) the participation of tapasin in finding a 'good fit' for class I heterodimers 
D) recycling an MHC class I heterodimer if the peptide falls out of its peptide-binding groove 
E) upregulation of HLA-DM by interferon-γ.

Question 14

Which of the following is not a characteristic of immunoproteasomes?

Accepted Answer

A) They make up about 1% of cellular protein. 
B) They consist of four rings of seven polypeptide subunits that exist in alternative forms. 
C) They are produced in response to IFN-γ produced during innate immune responses. 
D) They produce a higher proportion of peptides containing acidic amino acids at the carboxy terminus compared with constitutive proteasomes. 
E) They contain 20S proteasome-activation complexes on the caps.

Question 15

When describing the various components of the vesicular system,which of the following is not included?

Accepted Answer

A) nucleus 
B) Golgi apparatus 
C) endoplasmic reticulum 
D) exocytic vesicles 
E) lysosomes.

Question 16

Explain how mycobacteria avoid immune recognition by T cells during infection.

Accepted Answer

The answer of Explain how mycobacteria avoid immune recognition by...

Question 17

Which of the following cell types does not express MHC class I?

Accepted Answer

A) erythrocyte 
B) hepatocyte 
C) lymphocyte 
D) dendritic cell 
E) neutrophil.

Question 18

Which of the following removes CLIP from MHC class II molecules?

Accepted Answer

A) HLA-DM 
B) HLA-DO 
C) HLA-DP 
D) HLA-DQ 
E) HLA-DR.

Question 19

B cells,transport of immunoglobulin to the membrane is dependent on association with two invariant proteins,Igα and Igβ.Which of the following invariant proteins provide this function for the T-cell receptor in T cells?

Accepted Answer

A) CD3γ 
B) CD3δ 
C) CD3ε 
D) ζ 
E) All of the above.

Question 20

The_____ refers to the complete set of HLA alleles that a person possesses on a particular chromosome 6.

Accepted Answer

A) isoform 
B) isotype 
C) oligomorph 
D) allotype 
E) haplotype.

Exam 5: Antigen Recognition by T Lymphocytes