Flashcards in Lecture 6: The Major Histocompatibility Complex Deck (18)
What is the MHC?
set of closely linked genetic loci that are important in determining fate of engrafted tissue
also play central role in control of cellular interactions for physiological immune responsiveness
What is the function of MHC gene products?
to present peptides to T lymphocytes (they constantly sample environment)
What are the 3 Class I HLAs in humans?
HLA-A, B, C (cell surface glycoproteins on all nucleated cells that regulate immune cell interactions)
HLA molcules present antigen to ______ T lymphocytes
What are the Class II HLA Loci?
Where are Class II molecules found in the body?
on APCs (dendritic cells, B cells, macrophages)
Where in the genome is the MHC found?
short arm of chromosome 6
What does the conformation of the Class I MHC molecule look like?
one alpha chain (Class I polypeptide) and one light chain B2 microglobulin
True or False: the B2 microglobulin is the same in all MHC class I molecules
True (the alpha chains differ)
Peptide binding cleft of MHC Class I is made of ___ and ____.
alpha 1 and alpha 2
the cytoplasmic tail of MHC Class I is made of ___
alpha 3 (traverses the cell membrane)
In terms of peptide length, MHC Class I binds _________ peptides and MHC Class II binds __________ peptides
What does the peptide binding cleft look like for MHC Class II?
one beta 1 and one alpha 1
True or false: B2 microglobulin is encoded within the MHC region of chromosome 6
What is the pattern of MHC antigen expression?
CO-DOMINANT (in other words, all 3 maternal and 3 paternal class I molecular types as well as Class II types are expressed)
Each individual has 2 half sets of MHC genes making them what?
What is the benefit of polymorphism in MHC?
can present wider diversity of environmental antigens