title: Deletion of the znuA virulence factor attenuates Actinobacillus pleuropneumoniae and confers protection against homologous or heterologous strain challenge.
abstract: The znuA gene is known to be important for growth and survival in Escherichia coli, Haemophilus spp., Neisseria gonorrhoeae, and Pasteurella multocida under low Zn(2+) conditions. This gene is also present in Actinobacillus pleuropneumoniae serotype 1; therefore, the aim of this study was to investigate the existence of a similar role for the znuA gene in the growth and virulence of this organism. A precisely defined ΔznuA deletion mutant of A. pleuropneumoniae was constructed based on the sequence of the wild-type SLW01 using transconjugation and counterselection. This mutation was found to be lethal in low-Zn(2+) medium. Furthermore, the ΔznuA mutant strain exhibited attenuated virulence (≥22-fold) as well as reduced mortality and morbidity in a murine (Balb/C) model of infection. The majority of the bacteria were cleared from the lungs within 2 weeks. The ΔznuA mutant strain caused no adverse effects in pigs at doses of up to 1.0×10(9) CFU/mL. The ΔznuA mutant strain induced a significant immune response and conferred 80% and 100% protection on immunised pigs against challenge with A. pleuropneumoniae strains belonging to homologous or heterologous serovars, respectively, compared to the blank controls. The data obtained in this study indicate the potential of the mutant ΔznuA strain for development as a live vaccine capable of inducing reliable cross-serovar protection following intratracheal immunisation.
authors.affiliation: Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China.
authors.forename: Fangyan
authors.initials: F
authors.lastname: Yuan
authors.affiliation: National Research Center for Veterinary Medicine, Luoyang Pulike Bio-engineering Co. Ltd., Luoyang 471003, Henan, China.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Liao
authors.affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
authors.forename: Wujin
authors.initials: W
authors.lastname: You
authors.affiliation: Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China.
authors.forename: Zewen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
authors.forename: Chengkun
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
authors.lastname: BinWang
authors.affiliation: Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China.
authors.forename: Danna
authors.initials: D
authors.lastname: Zhou
authors.affiliation: Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China. Electronic address: tyxanbit@163.com.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China. Electronic address: beiwc@mail.hzau.edu.cn.
authors.forename: Weicheng
authors.initials: W
authors.lastname: Bei
mesh_terms: D000189:Actinobacillus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001428:Bacterial Vaccines / Q000276:immunology*; D005260:Female; D007114:Immunization / Q000662:veterinary; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D017384:Sequence Deletion; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D014613:Vaccines, Attenuated / Q000276:immunology; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated; D037521:Virulence Factors
keywords: Actinobacillus pleuropneumoniae; Deletion mutant; Protection; Virulence; znuA gene