The antigen and the antibody.
D000906:Antibodies; D000917:Antibody Formation; D000937:Antigen-Antibody Reactions; D000941:Antigens; D001323:Autoantibodies; D001327:Autoimmune Diseases / Q000276:immunology; D006801:Humans; D007109:Immunity; D008208:Lymphatic System / Q000502:physiology; D012157:Mononuclear Phagocyte System / Q000502:physiology
D000906:Antibodies; D000941:Antigens; D001323:Autoantibodies