title: Immune responses and protective efficacy of a novel DNA vaccine encoding outer membrane protein of avian Pasteurella multocida.
abstract: Avian Pasteurella multocida is a causative agent of fowl cholera. Two proteins OmpH and OmpA are the major immunogenic antigens of avian P. multocida, which play an important role in inducing immune responses that confer resistance against infections. In the present study, we used pcDNA3.1(+) as a vector and constructed DNA vaccines with the genes encoding the two antigens mentioned above. These DNA vaccines include monovalent (pcDNA-OMPH, pOMPH and pcDNA-OMPA, pOMPA), divalent combination (pcDNA-OMPH+pcDNA-OMPA, pOMPH+pOMPA) and fusion of two gene vaccines (pcDNA-OMPH/OMPA, pOMPHA). The immune responses to these DNA vaccines were evaluated by serum antibody titers, lymphocyte proliferation assay and titers of a cytokines, IFN-γ. The protective efficacy after challenging with a virulent avian P. multocida strain, CVCC474, was evaluated by survival rate. A significant increase in serum antibody levels was observed in chickens vaccinated with divalent combination and fusion DNA vaccines. Additionally, the lymphocyte proliferation (SI value) and the levels of IFN-γ were both higher in chickens immunized with divalent combination and fusion DNA vaccines than in those vaccinated with monovalent DNA vaccines (P<0.05). Furthermore, the protection provided by divalent combination and fusion DNA vaccines was superior to that provided by monovalent DNA vaccines after challenging with the avian P. multocida strain CVCC474. And the protective efficacy in chickens immunized three times with the fusion DNA vaccine was equivalent to the protective efficacy in chickens vaccinated once with the attenuated live vaccine. This suggests that divalent combination and fusion DNA vaccines represent a promising approach for the prevention of fowl cholera.
authors: He Nan University of Science and Technology, Luoyang, PR China. qianggong79@yahoo.com.cn
authors: Qiang
authors: Q
authors: Gong
authors: Ning
authors: N
authors: Qu
authors: Mingfu
authors: M
authors: Niu
authors: Cuili
authors: C
authors: Qin
authors: Ming
authors: M
authors: Cheng
authors: Xiaofei
authors: X
authors: Sun
authors: Aiguo
authors: A
authors: Zhang
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D002645:Chickens; D005798:Genes, Bacterial; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D010326:Pasteurella Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D016979:Pasteurella multocida / Q000235:genetics / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology* / Q000517:prevention & control*; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology / Q000494:pharmacology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D019444:Vaccines, DNA; C067128:ompH protein, bacteria; C078167:OMPA outer membrane proteins; D007371:Interferon-gamma