魏氏梭菌毒素疫苗研制及其免疫家兔抗体消长规律

Producing Research of the C.perfringes Type A Toxoid Vaccine

从山东省莱芜、泰安、潍坊等3个养兔场发生疑似梭菌性下痢的病兔体内分离到3株魏氏梭菌,鉴定为A型。利用该分离菌株和A型魏氏梭菌标准株(CVCC37)所产外毒素经甲醛灭活并加入氢氧化铝胶佐剂吸附浓缩后制备了A型魏氏梭菌类毒素疫苗。对该疫苗分别进行了安全性检验、有效免疫剂量试验和接种家兔1～23周血清中抗毒素(Ab)消长规律研究。结果表明,魏氏梭菌外毒素用0.3%甲醛32h能够彻底灭活,并最大可能地保持其抗原性;制备的魏氏梭菌类毒素疫苗无毒副作用,安全可靠;用野毒株和标准株制备的类毒素疫苗对家兔的有效免疫剂量为2mL/只,免疫保护效果可靠;采用野毒株和标准株制备的类毒素疫苗免疫接种家兔后第2周血清抗毒素效价迅速升高,到第4周达最高峰,分别为6.6log2和7.125log2,较高抗体滴度维持约17周后缓慢下降,至23周时血清平均抗毒素滴度仍维持在4.0log2和3.4log2以上,所以,该类毒素疫苗的免疫保护期可以设定为6个月。

With C.perfringens field strain and standard strain the toxin was produced and it was inactivated by 0.3% formalin.Then it was mixed with 5% AI(OH)_3 and the C.perfringens toxoid vaccine was successfully produced.In order to test the immune protective period of the vaccine serum antibody′s growth and decline regulation of the rabbits was detected,which was immunized with the toxoid vaccine.From 7~th day,the serum antitoxin was detected and antitoxin titer were very low(1.125 log2 and 0.8 log2 respectively).Since the second week the antitoxin concentration was soon increased and amount to 4.875 log2 and 4.1 log2 respectively.They were reached highest titer with 7.125 log2 for standard strain and 6.6 log2 for field strain in 30 days after immunization.The high level antitoxin could be maintained for about 3 months.In the 23 rd week,the antitoxin titer was still preserved 4.0 log2 and 3.4 log2 respectively.By the t-test,there was no remarkable difference(P>0.05) between the antitoxin levels of two group rabbits.The results showed that this vaccine had high immunity effect.The immune protective period of the C.perfringens toxoid vaccine can arrive for 6 months.