6. MHC I and II Flashcards Preview

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Flashcards in 6. MHC I and II Deck (10):

MHC types / encoded by

MHC I and II / encoded by HLA genes


MHC I vs II according to loci

MHC I ( 1 letter) HLA A, HLA-B, HLA-C
MHC II ( 2 leeter HLA- DR, HLA-DP, HLA-DQ


MHC I vs II according to binding

MHC I --> TCR and CD8
MHC II--> TCR and CD 4


MHC I vs II according to expression (which cells express them)

MHC I --> All nucleated cells (not on RBCs)
MHC II--> antigen presenting cells (APCs)


MHC I vs II according to function

MHC I --> present ENDOGENOUSLY synthesised antigens (eg viral or cytosolic proteins ) to CD 8 cytotoxic cells
MHC II --> present EXOGENOUSLY synthesized antigens (eg bacterial proteins) to CD4 helper T cells


MHC I vs II according to antigen loading

MHC I --> Antigen peptides loaded onto MHC I in RER after delivery via TAP ( Transporter associated antigen processing)
MHC II --> antigen loaded following release of invariant chain in an acidified endosome


MHC I vs II according to associated proteins

MHC I --> b2 microglobulin
MHC II --> Invariant chains (CD 74)


MHC Structure I

α peptide , β2 microglobulin --> peptide binding groove


MHC II Structure

α peptide , β peptide, invariant chain


Invariant chain ( cd 74) - function

1. shape the peptide binding groove and prevent formation of closed conformation
2. prevent binding of peptides from the endogenous pathway to the groove
3. Facilitates MHC class II from the ER in vesicle