MHC and Tissue Compatibility Quiz

12 Questions

Which type of cells recognize peptide antigens displayed by MHC molecules?

T lymphocytes

What is the physiological role of MHC molecules?

To display peptides derived from microbial protein antigens to antigen-specific T lymphocytes

Which individuals are likely to accept grafts from each other?

Identical twins

Which of the following is true regarding human leukocyte antigens (HLAs)?

HLAs are analogous to MHC molecules identified in mice

What do the class I and class II MHC genes encode?

Molecules involved in antigen presentation

What is the meaning of polymorphism in the context of MHC genes?

The presence of many variants of these genes in the population

Which domains of the alpha chain in class I MHC molecules contain polymorphic residues?

Alpha 1 and alpha 2 domains

What is the function of the CD8 T cell coreceptor in class I MHC molecules?

Binds to the invariant alpha 3 domain

What is the typical length of peptides that can be accommodated in the peptide-binding cleft of class I MHC molecules?

8 to 9 amino acids long

What is the function of the CD8 coreceptor in T cell activation?

To recognize peptides displayed by class I MHC molecules

What is the difference between the α1 and α2 domains in class II MHC molecules?

The α1 domain is nonpolymorphic, while the α2 domain contains polymorphic residues

What is the role of the β2-microglobulin in MHC molecules?

To bind to the α3 domain of class I MHC molecules

Study Notes

Antigen Recognition and MHC Molecules

CD8+ T cells recognize peptide antigens displayed by MHC class I molecules
MHC molecules play a physiological role in presenting antigens to T-cells for recognition and response

MHC and Graft Acceptance

Identical twins are likely to accept grafts from each other due to their identical MHC makeup

Human Leukocyte Antigens (HLAs)

HLA genes are highly polymorphic, with many alleles, causing different individuals to have distinct HLA types
HLA genes are responsible for encoding MHC molecules

MHC Genes and Proteins

Class I MHC genes encode proteins that present endogenous antigens to CD8+ T cells
Class II MHC genes encode proteins that present exogenous antigens to CD4+ T cells
The polymorphism of MHC genes refers to the high degree of genetic variation between individuals

Class I MHC Structure and Function

The alpha 1 and alpha 2 domains of class I MHC molecules contain polymorphic residues
The CD8 T cell coreceptor binds to the alpha 3 domain of class I MHC molecules
The peptide-binding cleft of class I MHC molecules can accommodate peptides typically 8-11 amino acids in length
The CD8 coreceptor functions to stabilize the interaction between the T cell receptor and the MHC-peptide complex during T cell activation

Class II MHC Structure and Function

The α1 and α2 domains of class II MHC molecules are involved in peptide binding
The β2-microglobulin is a protein that associates with the α chain of class I MHC molecules to form a functional complex