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T cell differentiation (view source)
Revision as of 12:48, 9 September 2008
, 12:48, 9 September 2008→T-Cell Activation
* [[Lymphocytes - WikiBlood#T cells|T cells]] function only after recent activation by antigen.
* [[Lymphocytes - WikiBlood#T cells|T cells]] function only after recent activation by antigen.
* CD4 binds MHC class II.
* CD4 binds [[MHC - WikiBlood#MHC II|MHC class I]].
** [[Lymphocytes - WikiBlood#Helper CD4+|CD4+ T-cells]] therefore recognise antigen only in association with [[Adaptive Immune System - WikiBlood#Structure and Function of MHC Class I|MHC]] class II
** [[Lymphocytes - WikiBlood#Helper CD4+|CD4+ T-cells]] therefore recognise antigen only in association with [[MHC - WikiBlood#MHC II|MHC class I]]
* CD8 binds MHC class I.
* CD8 binds [[MHC - WikiBlood#MHC I|MHC class I]].
** [[Lymphocytes - WikiBlood#Cytotoxic CD8+|CD8+ T-cells]] recognise antigen only in association with [[Adaptive Immune System - WikiBlood#Structure and Function of MHC Class I|MHC]] class I.
** [[Lymphocytes - WikiBlood#Cytotoxic CD8+|CD8+ T-cells]] recognise antigen only in association with [[MHC - WikiBlood#MHC I|MHC class I]].
* Activation of [[Lymphocytes - WikiBlood#T cells|T cells]] requires two distinct signals.
* Activation of [[Lymphocytes - WikiBlood#T cells|T cells]] requires two distinct signals.
** '''Signal 1'''
** '''Signal 1'''
*** The interaction of the TcR with the antigenic peptide/MHC complex on the antigen presenting cell.
*** The interaction of the TcR with the antigenic peptide/[[MHC - WikiBlood|MHC]] complex on the antigen presenting cell.
** '''Signal 2'''
** '''Signal 2'''
*** The interaction of CD28 on the [[Lymphocytes - WikiBlood#T cells|T cells]] with its ligand, CD80, on the antigen-presenting cell.
*** The interaction of CD28 on the [[Lymphocytes - WikiBlood#T cells|T cells]] with its ligand, CD80, on the antigen-presenting cell.