A vaccine candidate for post-weaning diarrhea in swine constructed with a live attenuated Salmonella delivering Escherichia coli K88ab,K88ac,FedA, and FedF fimbrial antigens and its immune responses in a murine model |
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| Authors: | Jin Hur Barry D Stein John Hwa Lee |
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| Institution: | Veterinary Public Health, College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, Republic of Korea (Hur, Lee); Indiana Molecular Biology Institute, Indiana University, Bloomington, Indiana 47405, USA (Stein) |
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| Abstract: | In order to construct a novel vaccine candidate for preventing post-weaning diarrhea in swine, the individual genes for Escherichia coli K88ab, K88ac, FedA, and FedF fimbriae were inserted into a secretion plasmid pBP244 containing asd, lepB, secA, and secB. These were transformed into Salmonella Typhimurium Δlon ΔcpxR Δasd. Secretion of the individual recombinant fimbrial antigens was confirmed by immunoblot analysis. Groups 1 and 2 mice received a single oral dose of the vaccine mixture and S. Typhimurium carrying pBP244 only as a control, respectively. In groups 3 and 4, mice were primed and boosted with the vaccine mixture and S. Typhimurium carrying pBP244 only as a control, respectively. In general, all immunized mice had significantly increased serum immunoglobulin (Ig)G (P < 0.05) and intestinal secretory IgA against the individual fimbrial antigens compared with those mice in the control group. In the IgG2a and IgG1 titer assay, only IgG2a titer was increased in group 1, while both IgG2a and IgG1 titers were increased in group 3. Furthermore, the vaccine strains were not detected in the excreted feces of any immunized mice. Thus, the vaccine candidate can be highly immunogenic and be safe to the environment. |
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