Submitted to: Clinical and Vaccine Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2009
Publication Date: 4/1/2009
Citation: Olsen, S.C., Boyle, S.M., Schurig, G.G., Sriranganathan, N.N. 2009. Immune Responses and Protection Against Experimental Challenge after Vaccination of Bison with Brucella abortus Strains RB51 or RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes. Clinical and Vaccine Immunology. 16(4):535-540. Interpretive Summary: Brucella abortus is a disease that causes abortion and associated economic losses in infected cattle herds. The prevalence of B. abortus within bison in Yellowstone National Park poses a risk for reinfecting cattle. Due to the controversy regarding the pathology of Brucella in bison, we evaluated the immunogenicity and efficacy of a new recombinant brucellosis vaccine in bison. Our data suggest that the new vaccine strain does not induce more robust immunologic responses and is not more protective than the parental RB51 strain as a vaccine for bison. These data will be of benefit to the National Park Service and the states of Montana, Wyoming, and Idaho in their efforts to resolve the brucellosis problem in the Yellowstone National Park and surrounding areas. These data will also benefit regulatory personnel in their efforts to prevent transmission of brucellosis to cattle herds and direct the Brucellosis Eradication Program.
Technical Abstract: Vaccination is a tool that could be beneficial in managing the high prevalence of brucellosis in free-ranging bison in Yellowstone National Park. In this study, we characterized immunologic responses and protection against experimental challenge after vaccination of bison with Brucella abortus strains RB51 (RB51) or a recombinant RB51 strain overexpressing superoxide dismutase or wboA genes (RB51+SOD/wboA). Bison were vaccinated with saline, or 4.6 x 10**10 CFU of RB51 or 7.4 x 10**10 CFU of RB51+SOD/wboA (n=8/treatment). When compared to nonvaccinates, bison vaccinated with RB51 or RB51+SOD/wboA had greater (P<0.05) antibody responses, proliferative responses, and production of interferon-gamma to RB51 after vaccination. However, when compared to vaccination with the parental RB51 strain, bison vaccinated with RB51+SOD/wboA cleared the vaccine strain from draining lymph nodes faster. Immunologic responses of bison vaccinated with RB51+SOD/wboA did not exceed responses of bison vaccinated with RB51. Pregnant bison were intraconjunctivally challenged in midgestation with 10**7 CFU of B. abortus strain 2308. Bison vaccinated with RB51, but not RB51+SOD/wboA vaccinates, had greater protection from abortion, fetal/uterine, mammary, or maternal infection as compared to nonvaccinates. Our data suggests that the RB51+SOD/wboA strain is less efficacious as a calfhood vaccine for bison as compared to vaccination with the parental RB51 strain. Our data suggests that the RB51 vaccine is a currently available management tool that could be utilized to help reduce brucellosis in free-ranging bison.