Lecture 14. Major Histocompatability Comple (MHC) Molecules Flashcards
What are the two types of MHC molecule ?
- Human leucocyte class I antigens
- Human leucocyte class II antigens
What are MHC molecules coded for by ?
Genes in the MHC complex on chromosome 6 in humans
What are the two main functions of MHC molecules ?
- Present peptides
- Restrict T lymphocytes
When does transplant rejection not occur ?
If its autologous
When does transplant rejection happen ?
Allogenic
What is meant by congenic ?
Identical except for the genes that code for rejection
What do all nucleated cells produce ?
Class I MHC
Where are class II MHC restricted to ?
Antigen presenting cells
What can nucleated cells become ?
Cancerous
What is the immunoglobulin domain ?
Beta sheets held together by two disulphide bonds
What is essential for class I ?
B2m
What is the structure of an alpha helix in a class I MHC ?
Ends are close
What is the structure of a class II alpha helix ?
The ends are open
What is meant by hypervariable ?
Lots of mutation resulting in different amino acids
What sort of MHC does complement have ?
Class III
What is the structure of MHC II molecule ?
- alpha one
- alpha two
- beta one
- beta two
- peptide binding groove
What do MHC class II binding peptides bind into ?
A beta sheet
Where are dendritic cells found ?
Anywhere there are macrophages
Where does MHC I present to ?
CD8+ T-cells
What is the structure of HC I ?
Alpha chain with three domains, non covalently associated beta-2 microglobulin
What forms the peptide binding groove that is recognised by TCR ?
Alpha one and alpha two
What does alpha three do in MHC I ?
Binds CD8 Co-receptor
How would you describe the process of class I antigen processing and presentation ?
Endogenous
What does MHC I bind ?
Short peptides (8-10 amino acids long)
What is binding of the peptide stabilised by ?
Contacts between atoms at carboxy and amino terminal ends of peptide and invariant sites on end of MHC I peptide binding groove
What is the story with each MHC I binding ?
Binds many different peptides byt with common anchor residues
