Interferon-tau (IFNτ) acts locally on the endometrium to suppress estrogen and oxytocin receptor expression and block luteolysis in ruminants. Systemic administration of conceptus homogenates or recombinant ovine IFNτ does not block luteolysis or enhance pregnancy rates in sheep or cattle, respectively. However, IFNτ up-regulates expression of the antiviral protein Mx throughout the entire uterine wall during early pregnancy. These studies determined if conceptus-derived IFNτ also up-regulates Mx expression in components of the circulating immune system that migrate through the endometrial wall. In experiment one, peripheral blood mononuclear cells (PBMC) were isolated from ewes at D26 post-artificial insemination (AI) and Mx mRNA levels examined by Northern and slot-blot hybridization. Pregnancy resulted in a two-fold increase in Mx mRNA levels compared to bred, non-pregnant ewes at D26. In experiment two, PBMC were isolated from ewes at AI, and every three days from D9 to D30. Results showed a four-fold increase in Mx mRNA levels in PBMC from pregnant versus bred, non-pregnant ewes at D15. Increased Mx mRNA, which remained elevated through D30, was accompanied by increased levels of Mx protein. These results show that pregnancy recognition signaling rapidly induces Mx gene expression in PBMC, and are the first to suggest that IFNτ activates gene expression in components of the circulating immune system.
All Science Journal Classification (ASJC) codes
- Endocrinology, Diabetes and Metabolism