PROTECTIVE EFFECT OF GLYCOPROTEIN GC-RICH ANTIGEN AGAINST PSEUDORABIES VIRUS

A trial vaccine containing pseudorabies virus (PRV) glycoprotein gC as the main component showed excellent protection against virulent virus infection in pigs. Glycoprotein gC-rich antigen was prepared by hepar in affinity chromatography from PRV-infected cell lysates. The prepara tions were mixed with mineral oil adjuvant as a water-in-oil emulsion. Six-week-old pigs were immunized twice at two-week intervals with tri al vaccines containing 128,000, 12,800 and 1,280 HA units per dose of gC antigen. They were then challenged with a virulent PRV at day 7 aft er the final immunization. Neutralizing (NT) antibodies were produced with increase of antibody titers after challenge. Pigs immunized with 128,000 HA units per dose of gC survived and showed no virus shedding during the 2-week experimental period after the challenge. The role of cell-mediated immunity was examined using BALB/c mice, and induction of gC-specific cytotoxic T lymphocytes (CTLs) was detected by Cr-51 re lease assay. From these results with mice, it is inferred that cell-me diated immunity, especially CTL, may play an important role in the eff ectiveness of our trial vaccine in addition to humoral immunity.