FIG 6.
Protection from challenge in pigs vaccinated with an experimental trivalent vaccine based on the Om-O-PanAsia2, Om-A22, and Om-AsMOG recombinants. Pigs (n = 4) were vaccinated with the antigen (each 7.5 μg/2 ml) by intramuscular injection. Three chimeric viruses (Om-O-PanAsia2, Om-A22, and Om-AsMOG) were used to challenge pigs intradermally in the footpad with viral titers of 105.0 TCID50/0.1 ml on day 28 after vaccination. (A) Pigs 134 and 135 were not vaccinated, while pigs 136 to 139 were vaccinated. The clinical score, amount of virus excreted from the oral cavity, and viremia are shown for each pig. (B) Change in body temperature after challenge in vaccinated and nonvaccinated pigs. The normal range of body temperatures in pigs is 38.7°C to 39.8°C. (C) Titers of antibodies specific for NSPs after vaccination and challenge of vaccinated and nonvaccinated pigs. NSPs were detected by using a PrioCHECK FMDV NSP ELISA kit. (D) VN antibody titers in vaccinated and nonvaccinated pigs after vaccination and challenge. Homologous viruses were used for the test. The cutoff for a positive reaction in the VN test is >1:16, and that for a positive reaction in the NSP ELISA is >50% inhibition. DPV, days postvaccination; DPI, days postinfection.