title: An in vitro method for evaluating endotoxic activity using prostaglandin E(2) induction in bovine peripheral blood.
abstract: Severe side effects of veterinary vaccines, in particular Histophilus somni-containing vaccines for cows, have frequently been reported in Japan. These side effects are probably caused by endotoxins. Contamination levels of endotoxins could be monitored using the Limulus amebocyte lysate (LAL) test; however, the LAL test is not completely adequate for evaluation of in vivo endotoxic activities. In this study, we established a method for evaluating endotoxic activities using prostaglandin E2 (PGE2) induction in bovine peripheral blood. Blood and standard endotoxin, derived from Escherichia coli, were mixed and incubated. The concentration of induced PGE2 in the culture supernatant reached a maximum after 24-h incubation. A linear dose-response curve was observed for PGE2 concentration and the logarithmic transformed standard endotoxin concentration (5-5000 ng/ml). The endotoxic activity of H. somni in cows was the highest among those of several tested endotoxins. However, the LAL activities of H. somni were not as high as those of the other tested endotoxins. These results may provide a reason for the many report of side effects of H. somni-containing vaccines. The PGE2 detection assay described here could be a valuable method for evaluating the endotoxic activities of vaccines in cows.
authors.affiliation: National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1 Tokura, Kokubunji, Tokyo 185-8511, Japan. usuima@rakuno.ac.jp
authors.forename: Masaru
authors.initials: M
authors.lastname: Usui
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Nagai
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tamura
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D015232:Dinoprostone / Q000096:biosynthesis* / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D004340:Drug Contamination / Q000517:prevention & control; D004731:Endotoxins / Q000378:metabolism / Q000494:pharmacology*; D004926:Escherichia coli / Q000378:metabolism; D008033:Limulus Test / Q000379:methods / Q000592:standards; D015661:Pasteurellaceae / Q000276:immunology; D016871:Pasteurellaceae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary; D015203:Reproducibility of Results; D014612:Vaccines / Q000276:immunology / Q000378:metabolism / Q000592:standards; D019155:Veterinary Drugs / Q000276:immunology / Q000378:metabolism / Q000592:standards; D014730:Veterinary Medicine / Q000379:methods* / Q000592:standards
chemical_list: D004731:Endotoxins; D014612:Vaccines; D019155:Veterinary Drugs; D015232:Dinoprostone