Histocompatibility (redirected from histocompatible)

histocompatibility /his·to·com·pa·ti·bil·i·ty/ (-kom-pat?i-bil´it-e) that quality of being accepted and remaining functional; said of that relationship between the genotypes of donor and host in which a graft generally will not be rejected, a relationship determined by the presence of compatible HLA antigens.histocompat´ible

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his·to·com·pat·i·bil·i·ty (hst-km-pt-bl-t)

n.

A state or condition in which the absence of immunologic interference permits the grafting of tissue or the transfusion of blood without rejection.

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Histocompatibility

The major histocompatibility determinants are the human leukocyte antigens (HLA) and characterize how well the patient and donor are matched.

Mentioned in: Bone Marrow Transplantation

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histocompatibility,

n the compatibility of the antigens of donor and recipient of transplanted tissue.

histocompatibility testing,

n the determination of the compatibility of the antigens of donor and recipient before tissue transplantation. Usually follows a blood typing protocol.

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histocompatibility

the quality of a cellular or tissue graft enabling it to be accepted and functional when transplanted to another animal.

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histocompatibility antigen

genetically determined antigens present on the cell membranes of nucleated cells of most tissues, which incite rejection when tissues are grafted to a different individual and thus determine the compatibility of tissues in transplantation. Major histocompatibility antigens exert the strongest effect on transplanted tissues, while the many minor histocompatibility antigens, such as blood group substances and the secretory alloantigen system, have a weaker, though often highly significant role in graft rejection.

histocompatibility genes

genes that code for the histocompatibility antigens.

major histocompatibility complex (MHC)

a cluster of loci on one autosomal chromosome containing the genes that code for the major histocompatibility antigens. The best studied MHC is the H₂ complex of the mouse followed by the HLA (human leukocyte antigen) of humans. In other species it is further specified: the dog leukocyte antigen (DLA), the bovine leukocyte antigen (BOLA), the swine leukocyte antigen (SLA), etc.

MHC class I is a polymorphic set of transmembrane heterodimeric proteins consisting of an a chain, encoded within the MHC gene complex, associated noncovalently with ß₂-microglobulin expressed on nearly all nucleated cells and which form a trimeric complex with typically 9-mer peptides that are then transported and presented on the surface of the cells and serve as targets for cytotoxic T lymphocytes (CTL or Tc), CD8 cells. A major defense mechanism against viral infections.

MHC class II is a polymorphic set of transmembrane heterodimeric proteins that consist of noncovalently associated a and ß proteins, both encoded within the MHC gene complex. They form a trimeric complex with antigenic peptides, which may be up to 35-mers, in antigen presenting cells which are then transported to the surface of the cell for presentation to T helper lymphocytes. The basis for all T lymphocyte responses.