The effect of Ureaplasma diversum activated mononuclear leukocytes on the development and interferon-tau production by bovine IVF-derived embryos.

Ureaplasma diversum is an opportunistic pathogen of the bovine genital tract causing herd outbreaks of granular vulvitis, abortion and infertility. Early embryonic death probably contributes to reduction of the reproductive performance in cows, however, pathogenesis of the disease remains obscure. The aim of the study was to examine whether activation of mononuclear leukocytes by U. diversum may affect embryo development and IFN-tau production. Bovine peripheral blood mononuclear leukocytes were cultured with U.diversum antigen for 24 h. The levels of IL-1, TNF-alpha, NO and GM-CSF in the cell culture supernatants were measured. IVF-derived embryos were cultured in the presence of supernatants from activated leukocytes. The development of embryos until day 6 postinsemination and the rate of morulae/blastocysts were determined. IFN-tau production in supernatants of cultured embryos was examined by inhibition of a virally-induced cytopathic effect. The results showed that U. diversum stimulated mononuclear leukocyte production of IL-1, TNF-alpha and NO. Supernatants from U. diversum-activated cells did not impair the rates of the embryo development and blastocyst formation. The products of activated leukocytes increased the IFN-tau production by cultured blastocysts. This suggest that U. diversum infection provides leukocyte-mediated signals for developing embryos for generation of additional production of cytokine - an important component of innate immunity.