title: Generation of an attenuated strain oral vaccine candidate using a novel double selection platform in Escherichia coli.
abstract: 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.
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, Heilongjiang, People's Republic of China.
authors.forename: Wenxin
authors.initials: W
authors.lastname: Liu
authors.forename: Chaowen
authors.initials: C
authors.lastname: Yuan
authors.forename: Jun
authors.initials: J
authors.lastname: Bao
authors.forename: Weikun
authors.initials: W
authors.lastname: Guan
authors.forename: Zhiteng
authors.initials: Z
authors.lastname: Zhao
authors.forename: Xingyue
authors.initials: X
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.forename: Dandan
authors.initials: D
authors.lastname: Li
authors.forename: Dongfang
authors.initials: D
authors.lastname: Shi
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D057134:Antibodies, Neutralizing / Q000097:blood / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D004768:Enterotoxins / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology / Q000517:prevention & control*; D022361:Escherichia coli Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D010861:Fimbriae, Bacterial / Q000276:immunology; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D057134:Antibodies, Neutralizing; D000942:Antigens, Bacterial; D004768:Enterotoxins; D022361:Escherichia coli Vaccines; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D014613:Vaccines, Attenuated