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Major Histocompatability Complexes (view source)
Revision as of 15:42, 28 August 2008
, 15:42, 28 August 2008→Function
===Function===
===Function===
* MHC class II molecules bind antigenic peptides and present them to TCR on CD4+ T-cells
*MHC II presents '''exogenous''' (that is, derived from the ECF) peptides
* The antigen-binding groove is larger and more open than that of MHC class I
*Endocytosed antigen interacts with MHC II in the cytoplasm to form a complex:
** MHC II can therefore interact with larger peptides
**Antigen is endoycotsed from the ECF
**Lysosomes fuse with primary endosomes to digest the antigen to peptides
**MHC II is meanwhile being produced by the endoplasmic reticulum, along with an invariant chain chaperone
**These pathways (endoytotic and secretory) merge to allow interaction between the antigen and MHC II:
***The invariant chain is digested, leaving a CLIP peptide in the binding groove
***Foreign antigen then replaces the CLIP peptide
*The MHC II-antigen complex is then secreted to the cell surface for presentation to [[Lymphocytes - WikiBlood#Helper CD4+|CD4+ T-cells]]
* MHC class II are present on those cells that have antigen-processing ability
* MHC class II are present on those cells that have antigen-processing ability
=Interaction of MHC With Antigen=
=Interaction of MHC With Antigen=