MHC and Ag presentation PDF

In the Name of God Major Histocompatibility Complex and Ag presentation Hossein Asgarian-Omran Ph.D., Prof. of Immunology Dep. of Immunology, School of Medicine Mazandaran University of Medical Sciences...

In the Name of God Major Histocompatibility Complex and Ag presentation Hossein Asgarian-Omran Ph.D., Prof. of Immunology Dep. of Immunology, School of Medicine Mazandaran University of Medical Sciences Sari, Iran [email protected] [email protected] Ag Recognition by Receptors of Acquired Immune System T cell recognition by major histocompatibility complex Discovery of MHC Genes In the 1940s, a scientist named George Snell, who was trying to discover the cause of transplant tissue rejection, was able to identify the relevant genes in mice. Discovery of MHC Genes Immune response specific for X  Different types of MHC  MHC I (class I): antigen presentation to CD8 T- lymphocytes  MHC II (class II): antigen presentation to CD4 T- lymphocytes  ‫‪MHC Class I‬‬ ‫قطعات پپتيدي‬ ‫با طول ‪ 8-11‬اسيد آمينه‬ ‫‪44 to 47 kDa‬‬ ‫‪12 kDa‬‬ ‫قسمت اتصال‬ ‫به مولكول ‪CD8‬‬  ‫‪MHC Class II‬‬ ‫قطعات پپتيدي‬ ‫با طول ‪ 10-30‬اسيد آمينه‬ ‫‪32-34 kDa‬‬ ‫قسمت اتصال‬ ‫به مولكول ‪CD4‬‬  Characteristics of MHC genes  Short arm of chromosome number 6  In humans, called HLA (Human Leukocyte Antigen)  Polygenic  Codominant  The most polymorphic genes known (polymorphism)  Linkage disequilibrium  Inheritance of MHC genes Jack Jill Bo Kim Mo Lee DP 1 2 3 4 1 3 1 4 2 3 2 4 DQ DR B C A  Expression of MHC genes  MHC I: On the surface of all nucleated cells in the body  MHC II: APCs, Dendritic cells, macrophages, B lymphocytes, etc. Processing of antigens and presentation to T lymphocytes Antigen processing and presentation to CD8 T- lymphocytes Cartoon of MHC Class I Presentation Antigen processing and presentation to CD4 T- lymphocytes  Comparison between antigen processing and presentation in the MHC I and MHC II pathways. Functions of professional antigen-presenting cells Costimulatory molecules