DefinitionThis section has been translated automatically.
Professional Antigen Presenting Cells (APC) take up allergen molecules and break them down into fragments, small polypetides, which have an antigenic effect. MHC class II molecules attach the polypeptides and transport them to the cell surface. Only in this way can free antigens be actively presented by antigen presenting cells (APC) (so-called MHC restriction) and be recognized by cytotoxic T lymphocytes.
Acting as APCs:
The type of APCs with which a helper cell comes into contact significantly determines its functional differentiation into TH1, TH0 or TH2 cells. The long-term survival of some of these antigen-specific lymphocytes leads to the development of an immunological memory. Furthermore, APCs are also decisive for the immune tolerance of the organism.