[Antigen processing and antigen presentation by accessory cells of the immune system].
T lymphocytes do not recognize antigens directly, but only after certain molecular modifications, the so-called antigen processing. This process has been studied mostly in macrophages and recently in B cells as well. Antigen processing takes place in lysosomes, biochemically is a limited proteolysis and only after the reexpression on the cell membrane of macrophages epitopes are recognized by T cells in the context of MHC class II molecules (Ia antigens). This is called linked or cognate recognition. Experiments leading to these conclusions were discussed, the heterogeneity of accessory immune cells is shown, and as an antithesis the possibility emerges that processing is not conditio sine qua non. Antigen presentation by accessory cells is shown as a precondition for cognate recognition in MHC restricted T cell responses. The existence and specificity of class II-epitope associates, the conditions for their reexpression, the size of epitopes and the influence of accessory immune cells on the specificity of presentation were discussed, based on the literature until summer of 1984.
J
J
Langner
D000917:Antibody Formation; D000936:Antigen-Antibody Complex; D000938:Antigen-Presenting Cells / Q000145:classification / Q000276:immunology*; D000941:Antigens / Q000276:immunology*; D004594:Electrophysiology; D000939:Epitopes; D006801:Humans; D008247:Lysosomes / Q000502:physiology; D008264:Macrophages / Q000276:immunology; D008285:Major Histocompatibility Complex; D010587:Phagocytosis; D013500:Surface Tension; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D000936:Antigen-Antibody Complex; D000941:Antigens; D000939:Epitopes
Antigenprocessing und Antigenpräsentation durch akzessorische Zellen des Immunsystems.