Comparative study on antigenicity and immunogenicity of 26-28 kDa antigen and recombinant Sj26 (RSj26) of Schistosoma japonicum

This paper reports a comparison of the recombinant Sj26 (rSj26) antigen derived from the Philippine strain and the 26-28 kDa antigen isolated and purified from the Chinese strain of Schistosoma japonicum with respect to their antigenicity and immunogenicity. The results showed that there were obvious cross reactions between rSj26 and 26-28 kDa antigen when rSj26 antigen was tested against specific antibodies in sera of mice infected with the Chinese strain of S. japonicum or the 26-28 kDa antigen was tested against specific anti-rSj26 antibodies by ELISA, IFA and Western blotting. Both the 26-28 kDa and the rSj26 antigen had weak cross reactions with SEA antigen. The worm reduction rate after challenging with Chinese strain cercariae in mice immunized with rSj26 was 26-32%, similar to that in mice immunized with 26-28 kDa antigen. It is suggested that rSj26 antigen can induce a certain level of specific protective immunity in the host against infection by the Chinese strain of S. japonicum cercariae.