EVIDENCE FOR EXTENDED MAINTENANCE OF THE CORPUS-LUTEUM BY UTERINE INFUSION OF A RECOMBINANT TROPHOBLAST ALPHA-INTERFERON (TROPHOBLASTIN) IN SHEEP

Ovine trophoblastin (oTP) is a natural interferon of the class-II interferon-alpha-subfamily. Recombinant ovine trophoblastin (r.oTP), produced by genetic engineering, was purified by anion-exchange HPLC. The product exhibited a high degree of homogeneity ( > 98%), and similar immunological cross reaction and antiviral activity to natural oTP. Antiluteolytic activity of r.oTP was established by intrauterine injection in two groups of cyclic recipient ewes. Control group A included 10 ewes which received sterile BSA in saline twice daily for 8 days (from day 10-12 of oestrous cycle). Experimental group B included 17 ewes which received 80-mu-g (4 ewes), 170-mu-g (8 ewes) or 340-mu-g (5 ewes) r.oTP daily for 8 days. Maintainance of functional corpora lutea for 1 month or more was observed in 4 out of 5 ewes which received high doses of r.oTP. These results indicate that oTP alone extends luteal secretory activity.