Induction of antibody and protective responses in mice by Brucella O-polysaccharide-BSA conjugate

A Brucella conjugate vaccine was synthesized by covalently coupling the O-polysaccharide (PS) obtained from Brucella melitensis 16M, to bovine serum albumin (BSA). The conjugate (PS-BSA) was non-toxic for mice. When injected at two doses (10 or 1 micrograms) in mice, it induced the production of antibodies and the boost was shown to be efficient if administered after 10 weeks. Immunization of mice with 10 micrograms of conjugate conferred significant protection against virulent challenge with B. melitensis H38, similar to that obtained with the reference vaccine H38.