Evaluation of immunogenicity and protective efficacy of recombinantptfA of avianPasteurella multocida.
AvianPasteurella multocidais the causative agent of fowl cholera, a disease much affecting the poultry industry. In order to study the efficacy of the recombinant subunit vaccine constructed withptfA gene of avianP. multocida, theptfA gene fragment amplified by PCR from avianP. multocidawas cloned into the prokaryotic expression vector pET32a and the recombinant plasmid pET32a-ptfA was obtained. The pET32a-ptfA was expressed inEscherichiacoliBL21(DE3) and the target protein rPtfA was purified. The purified protein was then mixed with Freund's adjuvant and the recombinant subunit vaccine was obtained. Three groups of chickens labeled as rPtfA, attenuated live vaccine and PBS were vaccinated with the recombinant subunit vaccine, attenuated live vaccine and PBS, respectively. Serum antibodies, peripheral blood lymphocyte proliferation (PBLP) and interferon-γ (IFN-γ) level secreted by peripheral blood lymphocyte were tested. The immunized chickens were finally challenged with virulent avianP. multocidaand the protection rate was counted. Indirect ELISA showed the levels of antibodies in rPtfA and attenuated vaccine groups were most significantly higher than the other groups (P<0.01), and the former was slightly lower than the latter. Peripheral blood lymphocyte proliferation experiments and IFN-γ experiments indicated that SI value and the levels of IFN-γ induced by ConA in the two vaccine groups were significantly higher than those of the PBS groups (P<0.01), and that the attenuated vaccine group was higher than the rPtfA group. The protection rates of rPtfA and attenuated live vaccines were 45% and 75%, respectively. The results indicated that the PtfA recombinant subunit vaccine was capable of improving the immunity level and inducing a protective effect for the vaccinated chickens, but it was barely satisfactory.
Department of Biotechnology, College of Food and Bioengineering, Henan University of Science and Technology, Henan Engineering Laboratory of Livestock Disease Diagnosing and Food Safety Testing, Luoyang, 471023, China.
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Department of Biotechnology, College of Food and Bioengineering, Henan University of Science and Technology, Henan Engineering Laboratory of Livestock Disease Diagnosing and Food Safety Testing, Luoyang, 471023, China.
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Department of Biotechnology, College of Food and Bioengineering, Henan University of Science and Technology, Henan Engineering Laboratory of Livestock Disease Diagnosing and Food Safety Testing, Luoyang, 471023, China.
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Department of Biotechnology, College of Food and Bioengineering, Henan University of Science and Technology, Henan Engineering Laboratory of Livestock Disease Diagnosing and Food Safety Testing, Luoyang, 471023, China.
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Avain Pasteurella multocida; Immune efficacy; Recombinant subunit vaccine; rPtfA