表达CPB-ST融合蛋白工程菌株的免疫原性研究

已构建的能表达产气荚膜梭菌β毒素（ＣＰＢ）和大肠埃希氏菌ＳＴ融合蛋白（ＣＰＢＳＴ）的基因工程菌株ＢＬ２１（ＤＥ３，ｐＥＣＢＳＴ１）及其表达产物经动物试验证实没有毒性反应。用从ＩＰＴＧ诱导的工程菌株中提取的包涵体和经甲醛灭活的工程菌株全菌体制备抗原免疫小白鼠，攻毒试验结果表明，免疫小白鼠能分别抵抗１ＭＬＤ的Ｂ型产气荚膜梭菌强毒株（Ｃ５８－１）和产ＳＴ的大肠埃希氏菌工程菌株ＨＢ１０１（ｐＳＬＭ００４）的攻击。用灭活的全菌体免疫家兔后，其免疫血清能中和产气荚膜梭菌β毒素和大肠埃希氏菌ＳＴ的毒素活性。结果表明，构建的基因工程菌株ＢＬ２１（ＤＥ３，ｐＥＣＢＳＴ１）可以作为预防由产气荚膜梭菌β毒素和大肠埃希氏菌ＳＴ引起的幼畜腹泻的基因工程苗侯选菌株。

Studies on immunogenicity of the genetic engineering strain expressing Clostridium perfringens beta toxin and Escherichia coli heat stable enterotoxin (CPB ST) fusion protein

The established genetic engineering strain BL 21 expressing Clostridium perfringens beta toxin and Escherichia coli heat stable enterotoxin (CPB ST) fusion protein and the expressed products were confirmed to have no toxicity by animal tests. The antigens were prepared using the inclusion bodies extracted from IPTG induced geretic engineering strain and the whole strain formalin inactivated, with which mice were immunized and then were challenged. The test results showed that the inoculated mice were able to resist 1 MLD virulent strains of B type Cl. perfringens (C 58-1 ) and the genetic engineering strain HB 101 [WTBX]E.coli producing ST enterotoxin fucion protein. After rabbits were inoculated with the inactivated the whole organisms, the immunized sera were able to neutralized the activities of Cl. perfringens beta toxin and E.coli ST enterotoxin. The results indicated that the established genetic engineering strain BL 21 may be used as the candidate strairs that was used to produce vaccine preventing Cl. perfringens beta toxin and E.coli ST enterotoxin caused diarrhea in young animals.