title: Brucella suis strain 2 vaccine is safe and protective against heterologous Brucella spp. infections.
abstract: Brucellosis is a wide spread zoonotic disease that causes abortion and infertility in mammals and leads to debilitating, febrile illness in humans. Brucella abortus, Brucella melitensis and Brucella suis are the major pathogenic species to humans. Vaccination with live attenuated B. suis strain 2 (S2) vaccine is an essential and critical component in the control of brucellosis in China. The S2 vaccine is very effective in preventing brucellosis in goats, sheep, cattle and swine. However, there are still debates outside of China whether the S2 vaccine is able to provide protection against heterologous virulent Brucella species. We investigated the residual virulence, immunogenicity and protective efficacy of the S2 vaccine in BALB/c mice by determining bacteria persistence in spleen, serum antibody response, cellular immune response and protection against a heterologous virulent challenge. The S2 vaccine was of low virulence as there were no bacteria recovered in spleen four weeks post vaccination. The vaccinated mice developed Brucella-specific IgG in 2-3 weeks, and a burst production of IFN-γ at one week as well as a two-fold increase in TNF-α production. The S2 vaccine protected mice from a virulent challenge by B. melitensis M28, B. abortus 2308 and B. suis S1330, and the S2 vaccinated mice did not develop any clinical signs or tissue damage. Our study demonstrated that the S2 vaccine is of low virulence, stimulates good humoral and cellular immunity and protects animals against infection by heterologous, virulent Brucella species.
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, State Key Laboratory for Agrobiotechnolgy, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, China; China Institute of Veterinary Drug Control, Beijing, China.
authors.forename: Liangquan
authors.initials: L
authors.lastname: Zhu
authors.affiliation: College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Feng
authors.affiliation: China Institute of Veterinary Drug Control, Beijing, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Zhang
authors.affiliation: China Institute of Veterinary Drug Control, Beijing, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.affiliation: College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: China Institute of Veterinary Drug Control, Beijing, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.affiliation: China Institute of Veterinary Drug Control, Beijing, China. Electronic address: dingjiabo@126.com.
authors.forename: Jiabo
authors.initials: J
authors.lastname: Ding
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, State Key Laboratory for Agrobiotechnolgy, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, China. Electronic address: suoxun@cau.edu.cn.
authors.forename: Xun
authors.initials: X
authors.lastname: Suo
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D058491:Bacterial Load; D002004:Brucella Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D041021:Brucella suis / Q000276:immunology*; D002006:Brucellosis / Q000517:prevention & control*; D056738:Cross Protection; D004195:Disease Models, Animal; D064789:Immunity, Heterologous; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008807:Mice, Inbred BALB C; D044967:Serum / Q000276:immunology; D013154:Spleen / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000907:Antibodies, Bacterial; D002004:Brucella Vaccine; D007074:Immunoglobulin G; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma
keywords: Antibody response; Bacterial persistence; Brucella suis S2 vaccine; Cellular immunity; Heterologous challenge; Protective efficacy; Virulence