Cellular antigen (synonym - tissue antigen) is an antigen that is present on the surface of the cells of the body.
Cellular antigens are markers by which the immune system recognizes “self” cells and distinguishes them from “foreign” ones. Main types of cellular antigens:
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Histocompatibility antigens (HLA in humans, MHC in animals) are located on the surface of all cells and are necessary for recognizing “self” and “foreign”.
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Differentiation antigens - expressed on cells of certain tissues and organs, allowing them to be recognized.
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Oncoantigens appear during oncological transformation of a cell.
Recognition of cellular antigens underlies the functioning of the immune system. For example, HLA antigens are needed for organ transplantation to avoid rejection. Antibodies to oncoantigens are used to diagnose and treat cancer. Thus, cellular antigens have important biological and medical significance.