Production of alpha interferon in Cowdria ruminantium-infected cattle and its effect on infected endothelial cell cultures.
Cattle that resisted experimental heartwater infection caused by the rickettsia Cowdria ruminantium produced significant levels of circulating alpha interferon (IFN-alpha), whereas animals that died from heartwater did not. In vitro, recombinant bovine IFN-alpha was found to significantly reduce the yield of Cowdria organisms in bovine endothelial cells, but even at a high concentration (1,000 U/ml), IFN-alpha did not completely prevent the growth of Cowdria organisms in these cells. This limited inhibitory effect of IFN-alpha is in agreement with the in vivo situation where an infectious process has to take place to induce a protective immune response. Our results suggest that IFN-alpha produced in vivo in response to Cowdria infection may represent an efficient way to slow down the infection and allow the animal to mount a protective immune response. IFN-alpha is the first endogenously produced factor shown to have anti-Cowdria activity.
Totté
P
P
Faculty of Sciences, Université Libre de Bruxelles, Belgium.
Jongejan
F
F
de Gee
A L
AL
Wérenne
J
J
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D002417:Cattle; D002478:Cells, Cultured; D016995:Ehrlichia ruminantium / Q000187:drug effects* / Q000276:immunology; D004730:Endothelium, Vascular / Q000382:microbiology*; D005260:Female; D006357:Heartwater Disease / Q000276:immunology* / Q000378:metabolism; D007370:Interferon Type I / Q000494:pharmacology*; D016898:Interferon-alpha / Q000096:biosynthesis*; D011994:Recombinant Proteins
D000907:Antibodies, Bacterial; D007370:Interferon Type I; D016898:Interferon-alpha; D011994:Recombinant Proteins