HLA and Disease Flashcards
1
Q
How are HLA genes expressed?
A
Co-dominantly
2
Q
What cells express MHC Class I molecules?
A
All nucleated cells and platelets
3
Q
What cells express MHC Class II?
A
Antigen presenting cells
4
Q
Where do MHC Class I polymorphisms tend to cluster around?
A
Peptide binding cleft
5
Q
Why are some T cells eliminated in the medulla?
A
If they have a very high affinity for self-MHC and self-peptides
6
Q
Thymocytes recognising MHC Class I become what kind of T cells?
A
CD8+
7
Q
Thymocytes recognising MHC Class II become what kind of T cells?
A
CD4+
8
Q
what is ankylosing spondylitis?
A
Chronic inflammatory arthritis of axial skeleton
9
Q
Why does absence of Asp 57 in DQB increase risk of type 1 diabetes?
A
- Cannot form salt bridge with Arg on alpha helix
- So molecule can be ‘more floppy’ and may be more likely to recognise self MHC
10
Q
What link between HLA alleles and autoimmune disease is hypothesised?
A
- HLA alleles influence T cell repertoire selection
- HLA alleles bind self-peptides too poorly to drive negative selection of self-reactive thymocytes
