Immunogenecity of a Brucella abortus S19 Glyco-conjugate Vaccine Consisting of Lipo-polysaccharide and Outer Membrane Protein in Cattle Calves

A glyco-conjugate vaccine consistingof lipopolysaccharide (LPS) and the outer membrane protein (OMP) of Brucella abortus S19 strain was prepared. Cattle calves were inoculated with 50 μg of the glyco-conjugate vaccine. Separate group of calves was vaccinated with live, attenuated B. abortus S19 vaccine. The humoral immune response in calves was assessed by an indirect ELISA on days 21, 60, 90 and 120 postvaccination. The glyco-conjugate vaccine was able to induce strong and comparable immune response against both components like the live, attenuated S19 vaccine. The IgG1 and IgG2 subtypeswere prominent in the antibody response. In addition, the glyco-conjugate vaccine was able to induce a cell mediated immune response as indicated by the expression of IFNγ in a whole blood stimulation assay using inactivated whole bacterial antigen or OMP. In these aspects the glyco-conjugate vaccine was similar to the live, attenuated S19 vaccine. Results of the study indicate that the glyco-conjugate vaccine may be a useful vaccine for inducing potent immune responses in cattle.