title: Construction of Bifidobacterium infantis as a live oral vaccine that expresses antigens of the major fimbrial subunit (CfaB) and the B subunit of heat-labile enterotoxin (LTB) from enterotoxigenic Escherichia coli.
abstract: We sought to develop Bifidobacterium infantis (BI) as a vehicle for the expression of heterologous antigens. Two proteins of enterotoxigenic Escherichia coli (ETEC) were expressed in BI: CfaB, a major fimbrial subunit protein, and LTB, the B subunit of heat-labile enterotoxin. The expression of CfaB and LTB in BI was verified by electrophoretic analysis. Sprague-Dawley rats were then subjected to intragastric immunization with BI-CfaB and BI-LTB systems both separately and together. ELISA was used to characterize the serum and mucosal immune responses against ETEC antigens. The immunized rats were intraperitoneally challenged with wild-type ETEC H10407 to study the immune response in vivo. The serum titres of IgG and faecal IgA antibodies in the BI-CfaB plus BI-LTB mixed vaccination group were significantly greater than those in the other two groups, which were immunized with a single vaccine (P<0.05). However, no significant difference was seen between the two groups that received a single immunization. These results suggest that expressing CfaB and LTB in BI provides a probiotic system with immunogenic properties. Furthermore, the expression of LTB in BI preserved its mucosal adjuvant effect. So this study confirms that BI can be used as a novel oral vaccine expression system for a heterologous antigen and BI-LTB can provide mucosal adjuvant properties.
authors: Key Laboratory of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
authors: Yongping
authors: Y
authors: Ma
authors: Key Laboratory of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
authors: Yaolin
authors: Y
authors: Luo
authors: Key Laboratory of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
authors: Xueping
authors: X
authors: Huang
authors: Key Laboratory of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
authors: Fangzhou
authors: F
authors: Song
authors: Key Laboratory of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
authors: Geli
authors: G
authors: Liu
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D001644:Bifidobacterium / Q000235:genetics* / Q000378:metabolism; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics* / Q000276:immunology; D004768:Enterotoxins / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D004927:Escherichia coli Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D029968:Escherichia coli Proteins / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D036781:Fimbriae Proteins / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D001427:Bacterial Toxins; D001428:Bacterial Vaccines; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D014613:Vaccines, Attenuated; D036781:Fimbriae Proteins; C027538:heat-labile enterotoxin, E coli