title: Antiinflammatory effects of endotoxin. Inhibition of rabbit polymorphonuclear leukocyte responses to complement (C5)-derived peptides in vivo and in vitro.
abstract: Although capable of provoking a variety of inflammatory effects, endotoxin (bacterial lipopolysaccharide) paradoxically has been reported to be antiinflammatory. The authors have found that single intravenous injections of Escherichia coli endotoxin, 24 hours before challenge, inhibit almost completely the vascular permeability changes and exudation of polymorphonuclear leukocytes induced in rabbit skin by reversed passive Arthus reactions. Whereas intravenous injections of endotoxin also caused modest inhibition of the vascular permeability changes induced in rabbit skin by the synthetic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP), exudation of polymorphonuclear leukocytes was unaffected. Polymorphonuclear leukocytes from rabbits given single injected doses of endotoxin exhibited markedly diminished chemotactic and degranulation responses to complement (C5)-derived peptides in vitro. Responses of these cells to FMLP, however, were normal. These data suggest that selective suppression of polymorphonuclear leukocyte responses to C5-derived peptides accounts, in part, for the antiinflammatory effects of endotoxin.
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001183:Arthus Reaction / Q000276:immunology; D002199:Capillary Permeability / Q000187:drug effects; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D003182:Complement C5 / Q000276:immunology / Q000494:pharmacology*; D004731:Endotoxins / Q000494:pharmacology*; D004926:Escherichia coli; D005260:Female; D007165:Immunosuppression Therapy; D066298:In Vitro Techniques; D008247:Lysosomes / Q000201:enzymology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects*; D011817:Rabbits; D012867:Skin / Q000098:blood supply / Q000187:drug effects; D015054:Zymosan / Q000494:pharmacology
chemical_list: D000893:Anti-Inflammatory Agents; C026438:C5-peptide; D003182:Complement C5; D004731:Endotoxins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015054:Zymosan