In vitro effects of live and killed Brucella abortus on bovine cytokine and prostaglandin E2 production.

Live and gamma-irradiated-killed Brucella abortus strain 2308 increased interleukin 1 (IL-1), but not interleukin 2 (IL-2), interferon-gamma (IFN-gamma), or prostaglandin E2 (PGE2) production when incubated with normal bovine peripheral blood mononuclear cells (PBMC). Live B. abortus was more effective than killed B. abortus in stimulating IL-1 production by normal PBMC. Both live and killed B. abortus were equally effective in suppressing IL-2 and IFN-gamma production by Concanavalin A-stimulated PBMC. Incubation of PBMC with the cyclo-oxygenase inhibitor, indomethacin, blocked PGE2 synthesis, but did not further enhance IL-1 production or prevent suppressed IL-2 and IFN-gamma production that was induced by live and killed B. abortus. These results suggest that B. abortus-induced suppression of IL-2 and IFN-gamma production did not appear to be mediated by the suppressive prostaglandin, PGE2, or other cyclo-oxygenase metabolites.