表达小鼠精子受精素β胞外区减毒沙门菌疫苗株的构建

Construction of the Attenuated Salmonella Typhimurium Strain Expressing the Extracellular Domain of Mouse Sperm Fertilin β Subunit

目的 :构建表达鼠精子抗原受精素 β亚单位 (Fβ)胞外区的可口服减毒沙门菌活疫苗株。 方法 :设计一对引物 ,应用PCR方法获得Fβ 胞外区cDNA片断 ,将其插入表达载体pYA3 14 9中 ,构建重组质粒pFEC ,将该重组质粒转入鼠沙门菌疫苗株X4 63 2 ,获得杂合菌株X4 63 2 (pFEC)。该重组菌口服免疫雌鼠 ,通过ELISA方法检测其诱导雌鼠血清IgG抗体和阴道分泌物IgA抗体滴度变化。 结果 :此疫苗株X4 63 2 (pFEC)可稳定表达被Fβ 抗体识别的重组Fβ 胞外区蛋白 ,口服该菌株不但可激发雌鼠产生高水平血清抗重组Fβ 蛋白IgG抗体 ,而且在阴道分泌物中可出现一定程度抗重组Fβ 蛋白IgA抗体 ,无明显毒性作用。 结论 :X4 63 2 (pFEC)疫苗株的构建为研究以Fβ 为靶抗原的精子抗原避孕疫苗打下了基础。

Objectives: To construct a live oral vaccine strain expressing the extracellular domain of mouse sperm fertilin β subunit. Methods: The gene encoding the extracellular domain was obtained by polymerase chain reaction and inserted into the vector plasmid pYA3149. The resulting recombinant plasmid pFEC was transformed into the attenuated S.typhimurium vaccine strain X4632 and got the live vaccine strain X4632(pFEC). Female mice were immunized with the recombinant strain and their serum IgG titres and vaginal secretions IgA titres against to fertilin beta protein were detected using ELISA. Results: The recombinant extracellular domain protein expressed stably by X4632(pFEC) can be recongnized by the anti-fertilin β subunit antibody. High level serum IgG titres and some degree vaginal mucosal IgA titres in mice induced by oral immunization were detected. The strain had no biological toxicity. Conclusions: This live vaccine strain X4632 (pFEC) is worthy to be studied as an immune contraceptive vaccine using sperm fertilin β subunit.