Antiviral and antiluteolytic activity of recombinant bovine IFN-omega 1 obtained from Pichia pastoris

The gene coding for bovine interferon-omega 1 (BoIFN-omega 1) was recently cloned and expressed at high levels in the yeast Pichia pastoris, The recom binant BoIFN-omega 1 protein shows antiviral activity in different cell lin es and has an antiluteolytic effect in cyclic ewes, In this article, we des cribe a method for purification of BoIFN-omega 1 expressed in the methylotr ophic yeast P. pastoris and characterization of its activity in vivo. The r ecombinant protein secreted to the culture medium had low activity because of self-aggregation. BoIFN-omega 1 was solubilized using urea and desalting and finally purified by ion exchange chromatography on Q-Sepharose Fast Fl ow. The yield of purified product was approximately 300 mg/L of fermentatio n culture, with a specific antiviral activity of 10(8) IU/mg, Its purity wa s at least 80%. The biologic characterization of purified BoIFN-omega 1 was determined by induction of an antiviral state on ewes challenged with 100 lethal doses (LD) of Aujeszky virus and by the extension of the corpus lute um life span and interestrous interval in cyclic cows. Ewes treated with 2 x 10(6) IU/kg BoIFN-omega 1 were protected from Aujeszky virus infection. I n cows receiving an intrauterine infusion of 1 mg BoIFN-omega 1, equally di stributed between the two uterine horns, twice daily from day 14 to day 22 of the experimental estrous cycle, the lifespan of the corpus luteum (25 vs . 19 days) and the interestrous intervals (26 vs. 21 days) mere extended wh en compared with a control group (p < 0.05), We show that recombinant BoIFN -omega 1 purified from P, pastoris has high antiviral activity and is an ef fective antiluteolytic agent in cattle.