title: Modulation of the immune response by antibacterial antibodies.
abstract: Antibodies induced by the gram+ bacteria Micrococcus lysodeikticus exhibit different carbohydrate specificities and hence might cross-react with membrane glycoproteins and/or glycolipids of mammalian cells. Using a T cell derived lymphoid line, these antibodies were found to detect a membrane marker which is only exposed in confluent culture conditions on non-dividing cells. Such confluence related antigen (Cag) is a cryptic membrane antigen, which can be unmasked through membrane perturbating agents such as p-formaldehyde or through interactions with macrophages and macrophage derived factors. Anti-micrococcus antibodies appear also to affect functionally normal T lymphocytes. Thus such reagents drastically inhibit the murine T cell reactivity towards mitogens such as Con A and PHA provided, however, the mitogenic signal is delivered through peritoneal macrophages. Furthermore, anti-micrococcus antibodies induce activated T lymphocytes into mitogenesis, but not unprimed resting T cells. Hence the physiological activity of anti-micrococcus antibodies depends on the state of activation of the T lymphocyte, indicating the involvement of cryptic membrane molecules. The relevance of such phenomena to host-bacteria and host-parasite interaction will be discussed.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001666:Binding Sites, Antibody; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D008837:Micrococcus / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000954:Antigens, Surface