Major Histocompatibility Complexes Flashcards
MHC is a…
genetic complex
in ALL vertebrate species
MHC stands for
Major Histocompatibility Complex
MHC genes are….
polymorphic (come in MANY genetic forms)
Classes of MHC
MHC Class I
MHC Class II
MHC I Structure
PART PRESENTED TO T-CELLS:
alpha-1 bind to membrane. alpha-2 & -3 combined form peptide-binding cleft. B-2 microglobulin doesn’t contribute to it’s function.
MHC II Structure
PART PRESENTED TO T-CELLS:
B-2 and a-2 bind to cell membrane. b-1 and a-1 form peptide-binding cleft.
MHC I expressed by
ALL nucleated cells
MHC I present Ag to…
CD8 T-cells
MHC I presents Ags that are…
sythesized inside the cell
cytosolic pathogens
Types of Ags presented by MHC I
viral antigens
intracellular parasites
MHC II expressed by…
dendritic cells
macrophages
B-cells
MHC II present Ags to…
CD4 T-cells
MHC II presents Ags that are…
made outside the cell and internalized
intravesicular pathogens & extracellular pathogens & toxins
Types of Ags presented by MHC II
extracellular parasites
extracellular phase of intracellular parasites
MHC functions
transport intracellular antigens to the surface of a cell where the TCR can “see” it
MHC I Antigen Processing
Tumer antigen coding region in nueclues –> endogenously synthesized Ag –> proteasome –> peptides –> peptide enters ER & binds to MHC I –> MHC I + Ag go to Golgi then DGN –> cell membrane