Protection of mice against Brucella abortus by immunization with polyclonal anti-idiotype antibodies.

Polyclonal goat anti-idiotypic antibodies containing internal images which mimic Brucella abortus antigens were generated from rabbit polyclonal idiotypes specific for partially purified extract of B. abortus (PX III). The anti-idiotypic antibodies were purified using two-step immunoaffinity column chromatography. The presence of internal images was demonstrated by competitive inhibition analysis using an enzyme-linked immunosorbent assay. Several groups of BALB/c mice were vaccinated with the anti-idiotypic antibodies. The vaccinated mice showed a high serum titer of antibodies specific for B. abortus. When the vaccinated mice were challenged with a virulent B. abortus strain 2308, greater than 90% reduction of bacteria in the spleen as compared to the unvaccinated control groups was seen. Immunoblotting experiments using antiserum from vaccinated mice demonstrate the ability to distinguish vaccinated mice from B. abortus infected mice. Our data indicate that the anti-idiotypic antibody containing internal images of B. abortus may be used as a vaccine and the induced antibody can be distinguished by immunoblotting from antibodies generated by natural infection with B. abortus.