The Role of Trophoblast Interferons in the Maintenance of Early Pregnancy in Ruminants


Department of Animal Science, University of Tennessee, Knoxville, TN 37901-1071.


PROBLEM: Are the effects of ruminant trophoblast interferon-tau (IFN-τ) on uterine prostaglandin (PG) secretion a specific action of this cytokine and what are the effects of IFN-τ on expression of uterine genes not generally associated with pregnancy maintenance?

METHODS: The effects of IFN-τ and IFN-α on bovine uterine expiant and epithelial cell production of PGF and PGE2 were determined in the presence and absence of oxytocin (OT). The effects of intrauterine administration of IFN-τ were determined on uterine expression of retinol-binding protein (RBP) and transforming growth factor-beta (TGF-β) isoforms.

RESULTS: IFN-τ attenuated uterine endometrial secretion of PGF and PGE2 in vitro and diminish PG stimulation by OT. IFN-τ and IFN-α were observed to be equipotent. Intrauterine infusion of IFN-τ resulted in a significant decrease in steady-state RBP mRNA levels and expression of TGF-B1, 2, and 3 mRNA levels were lowest in IFN-τ treated animals.

CONCLUSION: Negative regulation of gene expression may be a general strategy in IFN activity. This may explain the similar activities of IFN-τ and IFN-α on a broad variety of cell types, including ruminant uterine endometrium.