A Brucella abortus S19 Glyco-conjugate Vaccine Consisting of Lipopolysaccharide and outer Membrane Protein Protects Mice against Challenge with Brucella abortus

Abstract

A glyco-conjugate vaccine using the lipopolysaccharide (LPS) and the outer membrane protein (OMP) of Brucella abortus S19 strain was prepared. The vaccine was administered in mice subcutaneously (25 µg LPS per dose). Separate groups of mice were also vaccinated with LPS, OMP or live, attenuated S19 vaccine. Mice were challenged 30 days post vaccination with B. abortus 544 strain. The LPS, OMP and LPS-OMP glyco-conjugate vaccinated mice were protected against the challenge. The percentage of animals protected with the sub-unit vaccines and the glyco-conjugate vaccine were comparable with the live, attenuated vaccine. The glyco-conjugate vaccine was able to induce strong immune response against both the components. The prominent isotypes were IgG1, IgG2a and IgG3. In addition, the glyco-conjugate vaccine was able to induce a cell mediated immune response as indicated by the expression of IFN γ by splenocytes. The study indicated that the glyco-conjugate vaccine may be a useful candidate for prophylactic use.