Molecular
Basis for Alloantigen Recognition
URole of T-cell receptors (TCR=s)
-TCR=s
may recognize donor antigens in two ways:
1.host TCR=s recognize donor MHC molecules on graft tissue
2.host TCR=s recognize donor MHC-peptide complexes on graft tissue
URole of THelper (CD4+) cells
-CD4 cells recognize MHC class II molecules on donor tissue and produce cytokines as follows:
1.IL-2 & IFN-(
activate TCytotoxic (CD8+) cells
2.IL-2, IL-4 & IL-5
activate
B-cells
3.TNF-$
& IFN-(
activate
macrophages
URole of TCytotoxic (CD8+) cells
-CD8 cells recognize MHC class I molecules on donor tissue with the help of CD4 cells.