猪链球菌2型三种重组表达蛋白对BALB/c小鼠的免疫保护性评价

将150只BALB/c小鼠随机分成5组。用猪链球菌2型pET32a-Sly、pET32a-38ku和pET32a-Sly-38ku表达的重组蛋白制备的疫苗,以及猪链球菌2型全菌灭活疫苗分别免疫A、B、C、D组小鼠,E组为生理盐水对照。首免后第2周加强免疫1次,二免后第2周,用致死量强毒猪链球菌2型四川分离株和江苏分离株以及马链球菌兽疫亚种安徽分离株攻毒,观察攻毒后对小鼠的免疫保护率。结果,A组与C、D组对猪链球菌2型感染的保护率差异显著(P<0.05),而C组与D组之间保护率无显著差异;A、B、C、D组之间对马链球菌兽疫亚种安徽分离株感染的保护率差异不显著;各免疫组的保护率极显著高于对照组。结果表明,3种重组疫苗具有良好的免疫原性,能对强毒株猪链球菌2型的攻击感染起到保护作用。

Assessment of protective efficacy of three recombinant protein vaccines against Streptococcus suis type 2 in BALB/c mice

The 150 BALB/c mice were divided randomly into 5 groups.Mice in Group A,B and C were vaccinated with the vaccines developed from the proteins expressed from plasmids pET32a-Sly,pET32a-38ku and pET32a-Sly-38ku,respectively,mice in Group D or E were injected with the dead Streptococcus suis type 2 vaccine or normal saline solution.On week 2 post-vaccination,all the mice were inoculated by booster immunization(BI),respectively.On week 2 post-BI,all the mice were challenged with a lethal dose of S.suis type 2 Sichuan strain and Jiangsu strain and Streptococcus equi subsp.zooepidemicus Anhui strain,respectively,and the protection rates of the vaccines were evaluated post-challenge.The protection rate(PR) against S.suis type 2 and S.equi subsp.zooepidemicus in Group A was significantly different from those in Group C and D,but no significant difference between Group C and D.The PRs against S.equi subsp.zooepidemicus were not significantly different among Group A,B,C and D.The PRs against all the strains in Group A,B,C and D were significantly higher than that in Group E.These results showed that the three recombinant protein vaccines had good immunogenicity and were able to induce protective immune responses in mice.