Humoral and cellular immune response in mice and dogs induced by a recombinant Echinococcus multilocularis antigen produced by a Salmonella typhimurium vaccine strain.

A gene fragment (II/3-10) from the cestode Echinococcus multilocularis coding for a species-specific antigen was expressed in the live attenuated Salmonella typhimurium vaccine strain LT2 M1C. The recombinant vaccine (S. typhimurium + pVM II/3-10) was assessed for its potential to induce both a humoral and cell-mediated immune response in mice and dogs. Both subcutaneous and peroral administration of the vaccine resulted in antibody synthesis and lymphocyte priming of C57BL/6J mice against S. typhimurium antigens as well as against the recombinant E. multilocularis antigen. Two vaccinated (subcutaneous and peroral) dogs showed a strong humoral immune response to S. typhimurium antigens and to the recombinant E. multilocularis antigen, but proliferation of peripheral blood lymphocytes was not detectable against the bacterial S. typhimurium antigens. Regarding the recombinant E. multilocularis antigen, borderline lymphocyte proliferation was demonstrated following subcutaneous and none following peroral administration of the recombinant vaccine to dogs.