title: Differential induction of NO synthesis by gram-positive and gram-negative bacteria and their components in bovine monocyte-derived macrophages.
abstract: The ability of Gram-positive and Gram-negative bacteria to promote the induction of NO synthesis in bovine monocyte-derived macrophages (MDM) was tested. Heat-killed Gram-negative organisms induced NO synthesis at low concentrations (optimum 0.2 to 2 microg/ml wet weight), regardless of the strain, and the response was only moderately enhanced by co-administration of recombinant bovine interferon-gamma (rboIFN-gamma). The activity was largely, but not exclusively, due to lipopolysaccharide (LPS), since it was largely abrogated by co-incubation with polymyxin-B. Diphosphoryl-lipid-A and rough-strain LPS were two orders of magnitude more active than monophosphoryl-lipid A, but two orders of magnitude less active than smooth-strain LPS, suggesting that O side chains contribute to increasing the affinity of LPS or to act as a costimulus. Gram-positive bacteria as single stimuli were four orders of magnitude less potent in inducing NO synthesis than Gram-negative organisms, but upon costimulation with rboIFN-gamma, some of them were excellent inducers of NO synthesis. A similar rboIFN-gamma-enhanced NO synthesis induction was also observed for zymosan, muramyl dipeptide, lipoteichoic acid and lipoarabinomannan, although to a lesser extent than for the whole heat-inactivated prototypic organisms. Thus, bovine macrophages exposed to rboIFN-gamma have mechanisms by which they universally react to bacterial compounds distinct from LPS by induction of NO synthesis.
authors.affiliation: Institute of Veterinary Virology, University of Berne, Berne, Switzerland.
authors.forename: T W
authors.initials: TW
authors.lastname: Jungi
authors.forename: P
authors.initials: P
authors.lastname: Valentin-Weigand
authors.forename: M
authors.initials: M
authors.lastname: Brcic
mesh_terms: D000818:Animals; D001427:Bacterial Toxins; D002417:Cattle; D004768:Enterotoxins / Q000378:metabolism; D005029:Ethylenediamines; D005260:Female; D016166:Free Radical Scavengers / Q000737:chemistry; D006090:Gram-Negative Bacteria / Q000502:physiology*; D006094:Gram-Positive Bacteria / Q000502:physiology*; D007371:Interferon-gamma / Q000502:physiology*; D008070:Lipopolysaccharides / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism* / Q000382:microbiology; D009000:Monocytes / Q000378:metabolism / Q000382:microbiology; D009569:Nitric Oxide / Q000096:biosynthesis*; D009573:Nitrites / Q000032:analysis; D013424:Sulfanilamides; D018089:Superantigens; D013682:Teichoic Acids / Q000378:metabolism; D014199:Trehalose / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D005029:Ethylenediamines; D016166:Free Radical Scavengers; C095000:Griess reagent; D008070:Lipopolysaccharides; D009573:Nitrites; D013424:Sulfanilamides; D018089:Superantigens; D013682:Teichoic Acids; C030107:enterotoxin F, Staphylococcal; C050016:lipoarabinomannan; D009569:Nitric Oxide; C009900:lipoteichoic acid; D007371:Interferon-gamma; D014199:Trehalose