减毒沙门菌携带CWP2-S基因抗贾第虫口服疫苗的免疫原性

Oral immunization with CWP2-S DNA vaccine delivered by attenuated Salmonella typhimurium induces strong mucosal IgA response

构建重组减毒沙门菌SL7207/p VAX1-CWP2-S,对其免疫效果进行检测。酶切连接法构建重组质粒p VAX1-CWP2-S,以电击转染的方式转入减毒沙门菌SL7207。体外连续培养检测重组减毒沙门菌SL7207/p VAX1-CWP2-S对质粒p VAX1-CWP2-S的携带稳定性;以重组减毒沙门菌SL7207/p VAX1作为对照,经口服喂饲的方式免疫清洁级雌性BALB/c小鼠,8周后处死,检测各组试验鼠血清中和小肠灌洗液中特异性Ig G和SIg A的水平。结果是重组减毒沙门菌SL7207/p VAX1-CWP2-S连续培养168 h后,质粒携带率为90%;口服免疫小鼠8周后,与对照组相比,重组减毒沙门菌SL7207/p VAX1-CWP2-S免疫组血清特异性Ig G抗体增高约4.4倍,小肠灌洗液中特异性SIg A抗体增高约6.67倍。表明重组CWP2-S减毒沙门菌株具有良好的免疫原性。

The DNA encoding the soluble fragment of CWP2（CWP2-S）was cloned into an expression plasmid p VAX1. Therecombinant CWP2-S/p VAX1 plasmid DNA was then transformed into the attenuated Salmonella typhimurium strain SL7207 byelectroporation. The BALB/c mice were orally immunized with 1×106attenuated Salmonella typhimurium strain SL7207/ p VAX1-CWP2-S. Eight weeks after the first immunization,all mice were sacrificed and the sera were collected to detect anti-CWP2-SIg G,and intestinal flush was collected to detect CWP2-specific secretory mucosal Ig A.Result 90% of bacteria maintained CWP2-S/p VAX1 plasmid after being cultured for 168 hours in antibiotic-free medium. The serological specific Ig G was increased 4.4times and mucosal specific Ig A increased 6.67 times in mice orally immunized with SL7207/p VAX1-CWP2-S compared with micegiven the PBS control.The result indicated CWP2-S DNA vaccine delivered by attenuated Salmonella typhimurium could effective-ly induce serological Ig G and mucosal Ig A response.