Generation of an attenuated strain oral vaccine candidate using a novel double selection platform in Escherichia coli

作者：Liu, Wenxin; Yuan, Chaowen; Bao, Jun; Guan, Weikun; Zhao, Zhiteng; Li, Xingyue; Tang, Jie; Li, Dandan; Shi, Dongfang^*

来源：Applied Microbiology and Biotechnology, 2015, 99(2): 855-867.

DOI：10.1007/s00253-014-6099-3

• Escherichia coli
• Mucosal vaccine
• Mice
• Enterotoxin

Live attenuated bacteria delivered orally are interesting tools for mucosal immunization. The objective of this study was to construct a novel counter-selection platform based on an attenuated wild-type Escherichia coli (E. coli) strain and to utilize it for the delivery of LTR192G-STaA13Q fusion protein as an oral vaccine. First, a counter-selectable marker, namely, PRPL-Kil, was inserted into an attenuated wild-type E. coli strain through the use of the red and G-DOC homologous recombination systems to construct the counter-selection platform, and PRPL-Kil was subsequently replaced by the LT192-STa13 fusion gene to construct the oral vaccine O142 (yaiT::LT192-STa13) (ER-A). Subsequently, BALB/c mice were orogastrically inoculated with ER-A. Our results showed that ER-A could induce the production of specific IgA and IgG against fimbriae (F41) and enterotoxins (LT and STa), with neutralizing activity in BALB/c mice. In addition, assays of cellular immune responses showed that the stimulation index (SI) values of immunized mice were significantly higher than those of control mice (P < 0.05), and revealed a marked shift toward Th2-mediated immunity. These findings suggest that ER-A is a suitable candidate for an oral vaccine strain to protect animals from enter toxigenic Escherichia coli (ETEC) infection.

• 出版日期2015-1
• 单位东北农业大学