title: The M949_1556 gene plays a role on the bacterial antigenicity and pathogenicity of Riemerella anatipestifer.
abstract: Riemerella anatipestifer is one of the most economically important pathogens of farm ducks worldwide. However, the molecular mechanisms regarding its antigenicity and pathogenicity are poorly understood. We previously constructed a library of random Tn4351 transposon mutants using R. anatipestifer strain CH3. In this study, M949_1556 gene inactivated mutant strain CH3ΔM949_1556 was identified by screening of the library using monoclonal antibody against R. anatipestifer serotype 1 lipopolysaccharide (LPS) (anti-LPS MAb) followed by sequence analysis. The mutant strain presented no reactivity to the anti-LPS MAb in an indirect ELISA. Animal studies showed that the median lethal dose (LD50) of CH3ΔM949_1556 was >10(10) colony forming units (CFU), which was attenuated more than 50 times, compared with that of wild-type strain CH3 (LD50=2×10(8) CFU). The bacterial loads in the blood of CH3ΔM949_1556 infected ducks were significantly decreased, compared with those of CH3-infected ducks. In addition, CH3ΔM949_1556 presented significant, higher susceptibility to complement-dependent killing than CH3 did in vitro. Furthermore, CH3ΔM949_1556 showed increased bacterial adhesion and invasion capacities to Vero cells. Immunization with CH3ΔM949_1556-inactived vaccine was effective in protecting the ducks from challenge with R. anatipestifer serotype 1 strain WJ4, serotype 2 strain Yb2 and serotype 10 strain HXb2, suggesting that the mutant strain CH3ΔM949_1556 could provide a broad cross-protection among R. anatipestifer serotypes 1, 2 and 10 strains. Our results demonstrated that the M949_1556 gene plays a role on the bacterial antigenicity and pathogenicity of R. anatipestifer.
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Jiechi
authors: J
authors: Zou
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Xiaolan
authors: X
authors: Wang
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Mingxing
authors: M
authors: Tian
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Shoulin
authors: S
authors: Cao
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Wanwan
authors: W
authors: Hou
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Shaohui
authors: S
authors: Wang
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Xiangan
authors: X
authors: Han
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
authors: Chan
authors: C
authors: Ding
authors: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China. Electronic address: yus@shvri.ac.cn.
authors: Shengqing
authors: S
authors: Yu
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial / Q000235:genetics*; D001422:Bacterial Adhesion / Q000235:genetics; D001483:Base Sequence; D002522:Chlorocebus aethiops; D003165:Complement System Proteins / Q000276:immunology; D004372:Ducks; D004797:Enzyme-Linked Immunosorbent Assay; D045826:Flavobacteriaceae Infections / Q000276:immunology / Q000662:veterinary*; D015723:Gene Library; D005798:Genes, Bacterial / Q000235:genetics*; D007114:Immunization / Q000662:veterinary; D008969:Molecular Sequence Data; D011201:Poultry Diseases / Q000276:immunology* / Q000382:microbiology*; D060494:Riemerella / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014709:Vero Cells; D014774:Virulence / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D003165:Complement System Proteins
keywords: Antigenicity; Pathogenicity; Riemerella anatipestifer