3株鸡大肠埃希菌地方分离株I型菌毛的免疫原性

Immunogenicity of Type I Pili of 3 Avian E.coli Strains

选择宁夏地区的大肠埃希菌3个优势血清型O15、O78、O18菌株,大规模培养后提取I型菌毛,制备天然菌毛亚单位疫苗,免疫接种7日龄雏鸡后通过攻毒试验和抗体水平测定评价疫苗的免疫效果。结果表明,未免疫鸡的死亡率为40%～100%,而免疫鸡用同源菌株攻毒后死亡率为0～10%,用异源菌株攻毒后死亡率为20%～70%,免疫组鸡肝脏、心包和气囊的病变程度均显著轻于未免疫鸡,免疫鸡血清内出现高滴度的ELISA抗体。

Three strains of different serotype （O15,O78 and O18）, which were the most common serotypes in Ningxia, were cultivated for preparing the subunit vaccine of natural type I pill of avian Escherichia coll. Immunogenicity of the subunit vaccine was evaluated in 7-day-old chickens by challenging with Escherichia coli virulent strains and antibody assay. The results showed that unvaccinated chickens suffered the mortality from 40 % to 100 %, while vaccinated chickens suffered 0-10% after challenged with homologous E. coli and 20 %-70% mortality when challenged with heterologous E. coll. Vaccinated chickens had lower pathological lesions in the liver, the pericardial sacs and air sacs than unvaccinated ones after challenge. The serum antibody was detected in vaccinated chickens by ELISA and the antibody titer was high.