بنام خداي زيبائيها
Major Histocompatibility complex OR MHC
MHC The principal function of T cells are : Defense against intracellular microbes Activation of other cells(B cells ,Macrophages ) peptide recognition by T and B cells is different. B cells recognize soluble as well as cell associated Ags In contrast ,T cells recognize peptide which is displaying only by APC in associated with MHC proteins.
MHC MHC genes are the most polymorphic genes MHC genes are codominantly expressed in each individual There are two main type of MHC:class I & II The physiologic function of MHC molecules is presentation of peptides to T cells ,control of immune responsiveness to all proteins and graft rejection MHC-I present cytosolic peptides to T cytotoxic cells and MHC-II present endocytosed peptides to Th cells
MHC genes
MHC –I structure
MHC-II structure
T cell receptor and MHC interaction
Polymorphism of class II HLA-DPA 12 HLA-DPB 88 HLA-DQA 17 HLA-DQB 42 HLA-DR >400
Polymorphism of class I HLA-A >280 HLA-B >500 HLA-C >130
MHC genes and graft rejection
HLA expression
Peptide presentation by MHC-II
Peptide presentation by MHC-I