重组SEF21脂质体口服疫苗对肠炎沙门菌感染的作用

目的 探讨制备脂质体包裹重组SEF21疫苗，并评价其在预防肠炎沙门菌（S. enteritidis）感染中的作用。方法 利用PCR获得SEF21基因，并连接至pET-28a（+）载体。将pET-28a（+）-SEF21在BL21（DE3）大肠埃希菌中表达，通过镍层析柱纯化高表达的rSEF21蛋白。制备脂质体包裹rSEF21疫苗，并对鸡进行2次免疫，然后利用S. enteritidis进行攻毒实验。ELISA检测血清以及肠内容物中的抗体效价。结果 所有被免疫鸡的血清及肠黏液中产生了高效价的IgG和IgA抗体。脂质体包裹rSEF21所免疫的鸡的粪便样本中S. enteritidis数量明显下降。结论 口服脂质体包裹的重组SEF21蛋白疫苗能有效保护鸡对抗S. enteritidis感染。

Oral immunization with liposome-associated rSEF21 vaccine against S. enteritidis infection

Abstract: Objective To prepare liposome-associated Salmonella enterica serovar enteritidis (S. enteritidis) fimbriae (rSEF21) vaccine and examine its effect for prevention of S. enteritidis infection. Methods The intact region encoding SEF21 was amplified from S. enteritidis by polymerase chain reaction (PCR) and subcloned into a prokaryotic expression vector pET-28a(+) to yield pET-28a(+)-SEF21. The rSEF21 protein was highly expressed in E. coli BL21 and purified by nickel affinity chromatography. Liposome-associated rSEF21 were prepared for oral immunization. Titer of IgA and IgG in the intestinal tracts and in sera were measured by ELISA. Two weeks after the booster immunization, the chickens were challenged orally with 2×106 colony-forming units (CFU) of live S. enteritidis, and fecal samples were examined for bacterial excretion from the intestinal tract. Results Oral immunization with liposome-associated rSEF21 elicited both systemic and mucosal antibody responses. Significantly less fecal excretion of S. enteritidis was observed in immunized chickens after challenge. Conclusion Oral immunization with liposome-associated rSEF21 vaccine led to a protective efficacy from S. enteritidis infection.