title: The B subunits of cholera and Escherichia coli heat-labile toxins enhance the immune responses in mice orally immunised with a recombinant live P-fimbrial vaccine for avian pathogenic E. coli.
abstract: This study aimed to investigate the adjuvant effect of recombinant attenuated Salmonella expressing cholera toxin B subunit (CTB) and Escherichia coli heat-labile enterotoxin B subunit (LTB) for the P-fimbriae subunit-based vaccine of avian pathogenic E. coli (APEC) in a murine model. The PapA-specific sIgA and IgG responses were significantly enhanced after immunisation with the Salmonella-PapA vaccine in the presence of CTB or LTB. The group immunised with the Salmonella-LTB strain promoted Th1-type immunity, whereas that immunised with the Salmonella-CTB strain produced Th2-type immunity. We concluded that both Salmonella-CTB and -LTB strains can enhance the immune response to PapA, and that the LTB strain may be a more effective adjuvant for APEC vaccination, which requires higher Th1-type immunity for protection. Thus, our findings provide evidence that immunisation with an adjuvant, LTB, is one of the strategies of developing effective vaccines against P-fimbriated APEC.
authors.affiliation: Chonbuk National University College of Veterinary Medicine and Bio-Safety Research Institute 561-756 Jeonju South Korea.
authors.forename: In-Gyeong
authors.initials: IG
authors.lastname: Oh
authors.affiliation: Chonbuk National University College of Veterinary Medicine and Bio-Safety Research Institute 561-756 Jeonju South Korea.
authors.forename: Chetan V
authors.initials: CV
authors.lastname: Jawale
authors.affiliation: Chonbuk National University College of Veterinary Medicine and Bio-Safety Research Institute 561-756 Jeonju South Korea.
authors.forename: John Hwa
authors.initials: JH
authors.lastname: Lee
keywords: APEC; CTB; LTB; Salmonella vaccine delivery; immune response