Lecture 6 - MHC Restriction Flashcards
What is ‘MHC restriction’?
The ability of T cells to ONLY recognise peptides in association with MHC, and thence only the peptides that an individual’s MHC molecules are capable of presenting.
What are the two protein chains of the MHC I molecule? Which one varies between individuals?
Alpha chain - varies between individuals
Beta-2 Microglobulin - highly conserved
Which part of the MHC I molecule interacts with the peptide being presented?
Alpha chain
Which cell types express MHC II?
Specialised antigen presenting cells only e.g dendritic cells, macrophages
What are the two chains of the MHC II molecule? Which varies between individuals?
Alpha chain
Beta chain
- both vary between individuals
Which chain/s of the MHC II molecule bind the antigen to be presented?
Both alpha and beta chains.
How many MHC I alpha chain polymorphisms are there per chromosome?
3; an individual will co-express 3 from each maternal and paternal chromosomes at once.
What is the maximum amount of different MHC I molecules an individual can express?
6
How many different MHC II molecules can an individual express?
Variable - many possible combinations between 4 alpha and 4 beta chains from each parent, though not all combinations are functional.
How does MHC polymorphism influence individual disease susceptibility?
Some MHC molecules are ‘better’ at presenting antigen from certain organisms that others. Some MHC are more self-reactive than others. Some MHC will be protective against a certain disease, which assists survival of a population
Name one situation where an entire population has identical MHC and are therefore at greater risk of extinction due to infectious disease.
Factory farmed chickens
Lab mice of the same strain
How did Devil Facial Tumour Disease occur?
Same/similar MHC molecules among tasmanian dvils - during fighting, inoculated neoplastic cells not rejected by second animal; proliferative tumour results.
