Out Membrane Protein DNA Vaccines for Protective Immunity against Virulent Avian Pasteurella Multocida in Chickens

Abstract

The DNA fragments of omph and ompa were amplified by PCR from avian Pasteurella multocida. These fragments were inserted into pCDNA3.1(+) vector to construct DNA vaccines as follows: pCDNA-OMPH (pOMPH), pCDNA- OMPA (pOMPA) and pCDNA-OMPH/OMPA (pOMPHA). The three plasmids were transfected into SP2 /0 cell in vitro. Expression of target genes were analyzed by indirect immunofluorescence. Four-weeks-old chickens were vaccinated with these DNA vaccines. The chickens injected with attenuated vaccine were positive control and the chickens injected with pCDNA3.1(+) were negative control. The serum antibodies were tested. Immunized chickens were challenged with virulent of avian Pasteurella multocida, the protection rate were counted. Results of ELISA showed the levels of antibodies in fusion DNA group were equivalent to group of attenuated vaccine, and significantly higher than the two single DNA groups (P<0.05). All the DNA vaccines could provide partial protection for chickens after the challenge. The protection rate of fusion DNA vaccine was higher than the attenuated vaccine, and the latter higher than the two single DNA vaccines. The results indicated DNA vaccines especially fusion DNA vaccines provide