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histocompatibility antigensGenetically determined glycoprotein groups situated on the outer membrane of all body cells to provide an identifying code unique for each person (except identical twins). These groups act as antigens and, in a foreign environment, provoke the production of antibodies against them. This is the basis of graft rejection. They are also called HLA antigens because they were first found on human white blood cells (leukocytes). There are three classes: class 1proteins are found on the surface of most cells, even on red blood cells; class 2 proteins are found on the surface of B cells, antigen-presenting cells and some endothelial cells; class 3 proteins are components of the complement system. See also MAJOR HISTOCOMPATIBILITY COMPLEX (MHC).
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
Proteins scattered throughout body tissues that are unique for almost every individual.
Mentioned in: Corneal Transplantation
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