Tissue Histocompatibility genes

HISTOCOMPATIBILITY COMPLEX The set of histocompatibility genes that are important in the acceptance or rejection of tissue grafts. 

MHC class I and II proteins, the presenters of peptides to T cells, were discovered because of their role in transplantation rejection. A tissue transplanted from one person to another or from one mouse to another is usually rejected by the immune system. In contrast, tissues transplanted from one identical twin to another or between mice of an inbred strain are accepted. Genetic analyses revealed that rejection occurs when tissues are transplanted between individuals having different genes in the major histocompatibility complex, a cluster of more than 75 genes playing key roles in immunity. The 3500-kb span of the MHC is nearly the length of the entire E. coli chromosome. The MHC encodes class I proteins (presenters to cytotoxic T cells) and class II proteins (presenters to helper T cells), as well as class III proteins (components of the complement cascade) and many other proteins that play key roles in immunity. 

Genetic analyses revealed that rejection occurs when tissues are transplanted between individuals having different genes in the major histocompatibility complex, a cluster of more than 75 genes playing key roles in immunity. 

The chromosomes of every vertebrate species contain a set of linked genes known as the major histocompatibility complex (MHC). Two animals with vastly different MHC genes will reject a xenograft very quickly. If the MHC genes differ by a little, then a tissue from one will be only slowly rejected by the other (Talmage, 1979). 

Lectins may be used as probes for the study of the organization of specific components of chromatin. Three glycoproteins (mol. wt. 6.9 x 10 , 1.25, and 1.35 x 10 ) have been isolated from the non-histone chromosomal proteins from rat liver nuclei. The H-2 major histocompatibility complex is a complex of genes on murine chromosome 17, and is recognised as controlling the rejection of tissue allografts. Of five major peptides isolated from a... 

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