Abstract: Objective  To clone and express adenine phosphoribosyltransferase gene of Schistosoma japonicum， and analyze its stage-specific transcription and expression at different developmental stages of S. japonicum.  Methods  Specific primers were designed according to the reported EST sequence of APRT1 gene （GenBank Accession No. AAW24796）. RT-PCR was used to investigate the differential transcription of SjAPRT1 gene during the developmental stages. The gene was cloned into pET28a(+) plasmid. The recombinant plasmid rSjAPRT1/pET28a(+) was transformed into E. coli BL21(DE3) and induced with IPTG. The recombinant protein was purified with Ni-NTA resin and analyzed by SDS-PAGE. The purified protein was used to immune New Zealand white rabbits to obtain the antiserum. Western blotting was used to investigate the immunogenicity and the differential expression of rSjAPRT1 at different developmental stages.  Results  RT-PCR result showed that the specific bands were detected in eggs， cercariae， schistosomula, and adult worms （561 bp）. Western blotting analysis showed that the recombinant protein （rSjAPRT1, about M_r 25 000） existed in eggs， schistosomula and adult worms. The recombinant protein was recognized by pooled sera of infected rabbits.  Conclusion   The recombinant protein （rSjAPRT1） shows specific immunoreactivity, and is detected in the stage of eggs, schistosomula, and adult worms.

Key words: Schistosoma japonicum, Adenine phosphoribosyltransferase, Immune activity