title: Immunomodulation by small molecular weight bacterial products.
abstract: Microbial products are known immunomodulators. Endotoxins derived from gram negative bacteria both enhance and suppress a wide variety of immune responses in vivo and in vitro, depending upon dose, concentration, form, and time of exposure. Studies in this laboratory have shown that a small molecular weight polysaccharide derivative from endotoxin has strong immunomodulatory effects, both in vivo and in vitro, similar to intact LPS. Injection of PS into mice or addition to normal mouse spleen cell cultures results in enhanced responses similar to that observed with LPS as well as with lipoteichoic acid derived from gram positive bacteria. The immunomodulatory activity, both in vivo and in vitro, was related to development of soluble serum factors, most likely interleukins. Similar soluble mediators were observed in vivo since post endotoxin or post LTA serum, when added in small quantities to normal mouse spleen cell cultures, mediated enhanced antibody responses. Normal spleen cell cultures exposed to these materials also released soluble mediators into the supernatants which enhanced the antibody response of normal spleen cell cultures. These observations support the view that similar to larger molecular weight cell wall components, small molecular weight substances such as polysaccharide derivatives, despite lack of toxicity share related mechanisms of enhancing immune responses.
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001402:B-Lymphocytes / Q000276:immunology; D001419:Bacteria / Q000276:immunology*; D002455:Cell Division / Q000187:drug effects; D002473:Cell Wall / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D010712:Phosphatidic Acids / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000494:pharmacology; D012756:Sheep; D013682:Teichoic Acids / Q000494:pharmacology
chemical_list: D000276:Adjuvants, Immunologic; D008070:Lipopolysaccharides; D010712:Phosphatidic Acids; D011135:Polysaccharides, Bacterial; D013682:Teichoic Acids; C009900:lipoteichoic acid