猪源马链球菌兽疫亚种灭活疫苗对小鼠的免疫效力评价

Efficacy of Inactivated Vaccine Based on Streptococcus equi subsp. zooepidemicus of Porcine Origin Against Virulent Challenge in Mouse Model

【目的】评价中国不同地区猪源马链球菌兽疫亚种分离株抗原性的差异,为猪链球菌病疫苗的研制提供指导。【方法】取从国内10省市分离的10株猪源马链球菌兽疫亚种分离株,分别制备灭活疫苗,免疫12周龄ICR小鼠,用同源菌株和ATCC35246株攻击。【结果】以同源菌株攻击免疫小鼠,除CG-74-63株外,其余菌株的保护率均在90%以上;而以异源菌株ATCC35246进行攻击,免疫小鼠的免疫保护率为80%～100%。【结论】中国不同地区的猪源马链球菌兽疫亚种分离株的抗原性差异不大,单一菌株制备的疫苗具有保护性。

【Objective】In order to evaluate the antigenic variability of Streptococcus equi subsp. zooepidemicus of pig origin isolated in different regions in China and provide a guidance for development of vaccine of Streptococcus. 【Method】Groups of 12-week-old inbred ICR mice （10 mice per group） were immunized with formalin-inactivated whole bacterium cells of one of the 10 local isolates in complete Freund’s adjuvant, respectively, followed by a booster with the same doses of bacterial culture emulsifield in incomplete Freund’s adjuvant four weeks later. Groups of vaccinated and control mice were intraperitoneally challenged with 5 LD50 homogenous strains or 1.6×10 5CFU of heterologous ATCC35246 strain two weeks post-vaccination. 【Result】The results showed that at least 90% immunized mice were protected against homogenous challenges except the immunized group of CG-74-63, and 80 or more immunized mice were protected against heterologous ATCC35246 challenge. 【Conclusion】There is no significient antigenic variability among the 10 Streptococcus equi subsp. zooepidemicus isolates of pig origin, the Streptococcus vaccine made one of vaccine strain can provided enough protection