MHC in Antigen Presentation Flashcards
What does the TCR recognize when interacting with an APC?
MHC
Polymorphic region
Peptide
All MHC I molecules are formed with these 2 structures
Alpha and beta2 microglobulin
This is essential for expression of all HLA class I molecules and is coded by a non MHC gene
Beta2 microglobulin
Where are the polymorphic binding residues found on an MHC I molecule?
Alpha 1 and alpha 2 domains
These make up the peptide binding groove on the MHC I molecule
Alpha 1 and alpha 2 domains
In what domain is diversity found in the MHC class I molecules?
Alpha domain
All MHC II molecules are formed with these 2 structures
Alpha and beta chain
Which structure of HLA-DR is nonpolymorphic?
Alpha chain
Which structure of the HLA-DR is highly polymorphic?
Beta chain - a lot of alleles
The alpha and beta chains of these MHC II molecules are polymorphic
HLA-DP and HLA-DQ
What type of allele dominance do MHC gene show?
Co-dominant; phenotype from both parents will be expressed
Think of how in blood type if parents are A and B, child will be AB
Expression of this MHC class can be induced by certain cytokines
MHC class II
These 3 cells are considered professional APCs
Dendritic cells
Macrophages
B cells
Only this group of cells makes MHC class II receptors
APCs
These residues in the MHC I have less variability and hold the peptide in place
Anchor residues
This influences peptide binding in the alpha 1 and alpha 2 domains of MHC I
Allelic variation
What is the clinical relevance of allele specific binding?
Allelic variation —> better or worse ability to bind with antigens
Can also contribute to better self-binding —> autoimmunity
Which MHC class is able to bind bigger peptides?
Class II
This MHC class is responsible for presenting exogenous antigens
Class II
What MHC class is responsible for presenting endogenous antigens?
Class I
What cell is able to transfer an exogenous antigen to MHC I?
Dendritic cells - this is called cross presentation
Allows them to activate cytotoxic cells
What is a risk associated with limited polymorphism in MHC genes?
Increased susceptibility to certain illnesses or not creating a desired response to a vaccine
