Self-major histocompatibility complex

Hess AD, hoburn C Immune tolerance to self-major histocompatibility complex class II antigens after bone marrowtransplan-tation role of regulatory cells. Biol Blood Marrow Transplant 2006 12 518-29. 

Human leukocyte antigens (HLA) Groups of genes found on the major histocompatibility complex, which contain cell-surface antigen-presenting proteins. The body uses HLA to distinguish between self-cells and non-self-cells. 

This provides potential defensive proteins directed at almost every imaginable invader. It also ensures that every individual has a set of proteins that labels its own cells as "self," and that virtually every individual on earth has cell surface proteins different from those of every other person. In both the innate and adaptive responses the immune system must carefully distinguish "self" from "nonself."36 37 In the innate system this discrimination developed during evolution of the host and its pathogens. In the adaptive system it depends upon interaction of the T cells with surface molecules, primarily those of the major histocompatibility complex (MHC). 

Major histocompatibility complex (MHC) proteins are essential components of the immune system (1). One speeific role is for them to bind and present cellularly derived peptides (-8-10 amino acids - MHC Class I peptides) at the cell surface. These peptides are subsequently challenged by cytolytic T-lymphocytes (CTL s) which are programmed to differentiate between self and exogenous peptides. T-cell recognition of these latter peptides initiates a response that ultimately results in cell lysis and death of the infected cell. Hence, structural characterization of such peptides could potentially result in the development of therapeutie treatments of a number of infectious disease states such as viral cancers, AIDS, and autoimmune disease. However, the task of sequencing such peptides is difficult since MHC class I proteins can bind and present 10,000-15,000 different cellularly derived peptides present at the sub-pieo-femtomole level (2,3). 

Major histocompatibility complex (MHC)— A set of genes responsible for most of the proteins on the surface of cells in the body that are responsible for recognition of self. ... 

Kappler JW, Staerz U, White J, Marrack PC Self-tolerance eliminates T cells specific for Mls-modified products of the major histocompatibility complex. Nature 1988 332 35-40. 

Major histocompatibility complex (MHC). A cluster of genes encoding cell surface antigens that are polymorphic within a species and have a crucial function in signalling between lymphocytes and cells expressing antigen and in recognition of self. 

The immune system also makes use of the ubiquitin-mediated pathway in the response to altered self-cells, particularly virus-infected cells. Viral proteins within the cytosol of infected cells are ubiquitinated and then degraded in pro-teasomes specially designed for this role. The resulting antigenic peptides are transported to the endoplasmic reticulum, where they bind to class I major histocompatibility complex (MHC) molecules within the ER membrane. Subsequently, the peptide-MHC complexes move to the cell membrane where the antigenic peptides can be recognized by c3rt otoxic T lymphocytes, which mediate the destruction of the Infected cells. 

---