EFFICACY OF A MIXED GLYCOPROTEIN VACCINE AGAINST PSEUDORABIES IN PREGNANT SOWS

A pseudorabies virus (PRV) glycoprotein-mixed vaccine was prepared by heparin-affinity chromatography from PRV-infected PK-15 cell lysates. in our previous study [8], the trial vaccine was induced protection wi th suppression of virus shedding in one-month-old pigs and generation of cytotoxic T lymphocyte (CTL) response in mice. In this study, the e ffect of the trial vaccine on suppression of both virus shedding and r eproductive failure in pregnant sows was examined. Three sows were vac cinated twice until one week before mating. Each of them was infected intranasally with 10(6) TCID50 of PRV on day 28, 54, or 85 after matin g, respectively. Three other sows were also mated and challenged at th e same time as the respective control. The vaccinated sows produced vi rus-neutralizing antibodies. Sows with high level of VN antibody lower ed the level and period of virus shedding after challenge. The maximum level of shed-virus titers in vaccinated sows were 10(1.25) to 10(3) times lower than controls. Vaccinated sows shed virus for 1 or 5 days, white controls shed for 8, 9, or 12 days. No abortion or stillbirth w as observed in vaccinated sows during pregnancy. On the other hand, co ntrol sow challenged at a late stage of pregnancy showed abortion and stillbirth. The results obtained here indicate that our trial vaccine is effective to prevent reproductive failure by pseudorabies virus.