1. بنام خداي زيبائيها

2. Major Histocompatibility complex OR
MHC

3. 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.

4. 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

5. MHC genes

7. MHC –I structure

8. MHC-II structure

9. T cell receptor and MHC interaction

11. Polymorphism of class II
HLA-DPA
HLA-DPB
HLA-DQA
HLA-DQB
HLA-DR >400

12. Polymorphism of class I
HLA-A >280
HLA-B >500
HLA-C >130

13. MHC genes and graft rejection

14. HLA expression

15. Peptide presentation by MHC-II

16. Peptide presentation by MHC-I