Genetic immunization of mice with DNA encoding the 23 kDa transmembrane surface protein of Schistosoma japonicum (Sj23) induces antigen-specific immunoglobulin G antibodies

The 23 kDa transmembrane surface protein of schistosomes is of recognized i nterest in studies of immune responsiveness in schistosomiasis. To examine the immunogenicity of the 23 kDa antigen of Schistosoma japonicum, Sj23, wh en delivered by genetic immunization mice were immunized using a DNA constr uct containing the Sj23 cDNA under the control of a CMV promotor Serologica l analysis of peripheral blood from immunized mice demonstrated that this c onstruct was able to induce the production of antigen-specific IgG antibodi es that recognized a schistosome antigen of 23 kDa in Western blots. Despit e inducing antigen-specific antibodies, the Sj23 DNA vaccine was unable to confer protection in immunized mice subjected to challenge with S.japonicum cercariae. Appropriate engineering of the unique structure of the Sj23 kDa transmembrane protein of schistosomes may provide a novel vehicle for expr essing foreign epitopes from other infectious agents or possibly, cancer an tigens, anchored to the surface of transfected cells.