PROTECTIVE EFFECT OF NAOH-EXTRACTED ERYSIPELOTHRIX-RHUSIOPATHIAE VACCINE IN PIGS

A vaccine was prepared from a NaOH-extracted antigen of the Kyoto stra in (serovar 2) of Erysipelothrix rhusiopathiae (E. rhusiopathiae) with an oil adjuvant, and was injected twice at 3-week intervals into SPF pigs and conventional pigs with maternal antibodies. After the second vaccination, IgG-GA titers of immunized SPF pigs were more than 256-fo ld at 3 weeks, and immunized pigs with maternal antibodies were 64-fol d at 7 weeks. The pig with maternal antibodies vaccinated once with li ve vaccine had less than 4-fold titers. The ELISA antibody titers whic h were measured by using the NaOH-extracted antigen showed similar tra nsition to the IgGGA antibody titers. All immunized pigs and nonvaccin ated control pigs were challenged with the strains Fujisawa (serovar l a) or Saitama-1 (serovar 2). After challenge exposure, all pigs immuni zed with the NaOH-extracted vaccine showed no clinical signs and survi ved, and the pig immunized with the live vaccine had a local rhomboida l lesion at the site of the injection. Nonvaccinated pigs developed ty pical symptoms of E. rhusiopathiae infection and one of them died. Aft er the autopsy, the challenge strains were not recovered from the main organs except tonsils of the pigs immunized with the NaOH-extracted v accine. These results indicated that the NaOH-extracted vaccine induce s a protective effect in pigs with maternal antibodies as well as in S PF pigs negative for such antibodies, and that 67-64, 62-60 kDa protei ns in the NaOH-extracted antigen play an important role in protecting against E. rhusiopathiae infection.