MHC Flashcards
(26 cards)
How many domains does the class one have
3 alpha domains, with a non MHC molecule stabilizer, B2 microglobulin
Group of class one molecules ensuring tolerance of the mother to the baby
G antigen
MHC class 1
Closed Accommodates 12- 10 amino acid chains Ubiquitous Bulging peptides Cd8 cells Uses IL 2, gamma IFN, GSSF, Tumor necrosis factor and lymphotoxin Cellular immune response One transmembrane attachment 2-3 pockets
MHC class 2
Open ends, more accommodating Accommodates13-18 AA chains Double transmembrane attachment Double chains Present only on apcs, immune competent cells CD4 cells Humoral immune response Uses IL4, 5, 6, 10 Flat peptides
Molecular weights of heavy and light chains of mhc 1
HEAVY CHAIN- 45,000
Light chain- 12,000
Molecular weights of heavy and light chains of mhc 2
Alpha chain;heavy chain- 33,000
Beta chain; light chain- 27,000
Chromosome coding b2 microglobulin
Chromosome 15
Chromosome coding for MHC
Chromosome #6
Mhc equivalent in mice and where is it located?
H-2 ; chromosome 17
Gene domain for class 1
HLA- A
HLA- B
HLA- C
Minor hlA molecules, EFG
Gene domain for class 2
HLA- D ONLY
Specifically DQ, DR, DP
Most highly polymorphic B gene
DR B - 18 known allelic polymorphisms
Allelic polymorphisms for class 1 genes
HLA -A; 530 alleles
HLA -B; 921 alleles
HLA -C; 312 alleles
MHC genes are considered; and inherited as a package
Codominant; haplotype with both chromosome pairs 6 having a set of alleles
Class 3 MHC codes for
Complement proteins (c4 and 2) and cytokines, factor b
Ranking for transplantation and immune response
Class one
Class two
Class three
Immune response: c2,c1,c3
Transplantation: c1, c2, c3
Similar for HLA and H-2
Class 3
Minor histocompatibility complex chromosome
23
Class 1 is found ubiquitously except in
RBCs and spermcells
Binding sites for mhc class 1
A2 and A1
Binding sites for mhc class 2
A1 and B2
Class one mhc site components and process
Made in the ER.
Calnexin holds the 3 domain alpha chain into a partially folded structure to allow binding of B2 microglobulin
The binding process happens in the ER
The proteins are degraded first by proteosomes, cleaved and then DELIVERED BY TAP1 and TAP2
Tapasin brings TAP into close proximity of mhc molecules and mediates interaction with them
It is then transferred at the cell membrane.
Class one mhc site components and process
Also made in the ER
Binding site is is within the phagocytic vesicles( endocytic)
Most potent activators for T cells are dendritic cells
The invariant chain, a 31kd molecule prevents interaction with endogenous peptides
Once bound to an invariant chain, it is transported in to a endosomal compartment(vesicle) and then waits for processed exogenous peptides
Once it encounters a peptide, the invariant chain is degraded into a CLIP(class 2 invariant chain peptide) and is exchanged for exogenous peptides (low ph favors this binding)
Peptide bonding present within class 2 mhc
Hydrogen bonds
