title: The interaction of macrophages and bacteria: Escherichia coli species, bacterial lipopolysaccharide, and lipid A differ in their ability to induce tumoricidal activity and the secretion of reactive nitrogen intermediates in macrophages.
abstract: The ability of nine Escherichia coli strains, and of bacterial lipopolysaccharide (LPS)3 and lipid A preparations, to elicit in a pure population of bone marrow-derived mononuclear phagocytes (BMM phi) tumoricidal activity and/or the generation of reactive nitrogen intermediates (RNI) was compared. Generally, low concentrations of E. coli organisms were able to trigger the generation of RNI: however, for induction of tumoricidal activity, higher concentrations were required. Nonisogenic E. coli species exhibited different ability; isogenic E. coli organisms that differed only in the expression of K antigen exhibited similar ability to elicit the macrophage activities. LPS proved to be highly efficient in triggering the secretion of reactive nitrogen intermediates; lipid A was clearly less potent, but evidence is presented to suggest that this was due to the diminished solubility of these reagents. On the other hand, all LPS and lipid A samples were very poor inducers of tumoricidal activity. Although RNI secretion and expression of tumoricidal activity are both strongly dependent on L-arginine, various evidence suggests that the two functions are not closely correlated and are induced by different bacterial structures.
authors.affiliation: Immunobiology Research Group, Institute for Immunology and Virology, University of Zurich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Keller
authors.forename: R
authors.initials: R
authors.lastname: Gehri
authors.forename: R
authors.initials: R
authors.lastname: Keist
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D000954:Antigens, Surface / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D004926:Escherichia coli / Q000276:immunology*; D008050:Lipid A / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008262:Macrophage Activation / Q000276:immunology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009573:Nitrites / Q000276:immunology*; D011112:Polymyxin B / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; C030659:K antigens; D008050:Lipid A; D008070:Lipopolysaccharides; D009573:Nitrites; D014409:Tumor Necrosis Factor-alpha; D011112:Polymyxin B