IMMUNOGENICITY OF ATTENUATED PPV STRAIN_(s-1)A AND VACCINE PREPARED FROM IT
Ye Xiangyang; Zhang Wanhua; Pan Xuezhu; Xu Ping;Cao Weiming; Xu Yafen;Yan Zhenxiu (Animal Husbandry and Veterinary Research Institute, Shanghai Academy of Agricultural Sciences,Shanghai 200030, China.)
mL of attenuated PPV strains-1A preparation was injected intramuscularly to each of two gilts which showed HI titres of 128 and 256,respectively, 8 days after inoculation. They and other two HI-negative gilts(as control)were mated thereafter. The four were challenged with virulent PPV strain 38～40 days after conception when the previouslyinoculated two showed an HI titre of 1 280. Viremia was seen in the two control gilts but not inthe two previously inoculated with the attenuated strain.Viruses were recovered from the internal organs of 10 of all the 23 fetuses collected from the two control gilts 40 days after challenge but not from all the 25 fetuses of the previouslyinoculated ones. Eleven 5.5 month-old HI-negative piglets were inoculated respectively with 4 batches of vaccines prepared from the attenuated PPV strain s-1A and all showed antibody in blood within one week and the HI titre reached 599 in average after one month after inoculation. The eleven were challenged with virulent PPV strain 1～7 months after inoculation and no viruses were recovered thereafter.In contrast, 8 HI-negative control piglets showed HI titres ranging from 1 024 to 4 096 one week after challenge and viruses were recovered from the internal organs of all of them. The result showed that the vaccine prepared from the attenuated PPV strains-1A could produce an immunity which could last at least 7 months and the vaccine could keep a shelf-life of 11 months.
【CateGory Index】： S858.28