纤毛蛋白与绵羊白细胞介素2融合基因工程疫苗对实验动物的体液免疫应答

将转化节瘤拟杆菌（D.nodosus)纤毛蛋白（Pili）和绵羊白细胞介素2（oviIL2)融合基因表达质粒的工程菌BL－21，在含酸苄青霉素营养肉汤培养基中表达，离心获得菌体沉淀物，裂解后配制成Pili-oviIL2融合基因工程疫苗。用加佐剂和不加佐剂的Pili-oviIL2融合基因工程疫苗分别接种2只健康家兔，21天后接种第2次；定期采血，用对流免疫电泳检测试验兔的体液免疫反应。结果发现，加佐剂和不加佐剂的Pili-oviIL2融合基因工程疫苗免疫兔7天即可产生相应抗体，抗体在免疫血清中可维持6个月以上。进一步试验将不加佐剂的Pili-oviIL2融合基因工程疫苗接种3只健康绵羊，同样21天后接种第2次，定期采血，用对流免疫电泳检测试验绵羊的体液免疫反应。同时用Pili基因工程疫苗接种2只绵羊作对照。结果3只绵羊接种Pili-oviIL2融合基因工程疫苗后，分别于7天和14天产生相应的抗体，而接种Pili基因工程疫苗的绵羊于28天产生相应的抗体；被免疫绵羊血清中的抗体可维持6个月以上。用Pili-oviIL2融合基因工程疫苗接种兔和绵羊的免疫试验表明，Pili-oviIL2融合基因工程疫苗具有较好的体液免疫应答反应，重组OviIL2在融合基因工程疫苗中具有良好的佐剂作用。

Evaluation on Humoral Immune Response in Sheep and Rabbits Elicited by a Recombinant Fusion pili-oviIL2 Vaccine

A fusion pili and ovine IL_2 subunit protein was expressed by transforming the plasmid pmPiliIL2 harbouring pili gene and ovine IL2 gene into the competent host cell BL_21(DE3).A vaccine called fusion pili_oviIL2 vaccine was prepared from sonicated cell mixtures of the transformants with pili_oviIL2 fusion protein.Two rabbits of 2 groups were respectively inoculated subcutaneously with either a single fusion pili_oviIL2 vaccine or an emulsion of pili_oviIL2 vaccine with Freund's adjuvant,and each received the same dose at interval 3 weeks.Blood samples for test rabbits were taken for counter immunoelectrophoresis after inoculation at interval of one week to evaluate the antibody response.Three sheep in group 1 received two times of inoculation with either a single fusion pili_oviIL2 vaccine without any adjuvant and two sheep in group 2 received an emulsion of a recombinant pili vaccine with Freund's adjuvant.Humoral antibody response was evaluated as did for rabbits above.Results showed that the serum antibody was elicited at 7th day after first inoculation and sustained over 6 months in each of four test rabbits inoculated with fusion pili_oviIL2 vaccines with or without Freund's adjuvant.The same result was also observed in test sheep.The antibody response occurred in three sheep inoculated with a single pili_oviIL2 earlier at days 7 and 14 respectively while the antibody response for sheep inoculated with a recombinant pili vaccine was observed at 28th day. All of test sheep observed remained positive for antibody response over 6 months.Thus it can be derived that the single fusion pili_oviIL2 vaccine without any adjuvant elicited a high humoral immune response and the fusion oviIL_2 subunit in the vaccine had at least the same effective adjuvant activity in enhancing immunogenicity as Freund's adjuvant did.