THE ROLE OF TROPHOBLAST INTERFERONS IN THE MAINTENANCE OF EARLY-PREGNANCY IN RUMINANTS

PROBLEM: Are the effects of ruminant trophoblast interferon-tau (IFN-t au) on uterine prostaglandin (PG) secretion a specific action of this cytokine and what are the effects of IFN-tau on expression of uterine genes not generally associated with pregnancy maintenance? METHODS: Th e effects of IFN-tau and IFN-alpha on bovine uterine explant and epith elial cell production of PGF(2 alpha) and PGE(2) were determined in th e presence and absence of oxytocin (OT), The effects of intrauterine a dministration of IFN-tau were determined on uterine expression of reti nol-binding protein (RBP) and transforming growth factor-beta (TGF-bet a) isoforms. RESULTS: IFN-tau attenuated uterine endometrial secretion of PGF(2 alpha) and PGE(2) in vitro and diminish PG stimulation by OT , IFN-tau and IFN-alpha were observed to be equipotent. Intrauterine i nfusion of IFN-tau resulted in a significant decrease in steady-state RBP mRNA levels and expression of TGF-B1, 2, and 3 mRNA levels were lo west in IFN-tau treated animals. CONCLUSION: Negative regulation of ge ne expression may be a general strategy in IFN activity. This may expl ain the similar activities of IFN-tau and IFN-alpha on a broad variety of cell types, including ruminant uterine endometrium.