Abstract: 　Objective To explore antigens possessing common immunogenicity with Schistosoma japonicum (Sj) cercariae antigens, and to find out new candidate antigens for schistosomiasis diagnosis and vaccine. Methods Sj adult cDNA library was screened using sera from rabbits vaccinated with Sj cercariae antigen, the inserts of positive clones were amplified by PCR, all positive clones were sequenced and the data were analysed using Nucleotide BLAST software of NCBI and Expert Protein Analysis System of Swiss Institute of Bioinformatics. Results Thirteen positive clones were obtained after three rounds of immunoscreening, and all amplified by PCR.Among four novel genes, SjCAI, SjCA, SjCAI-2 and SjCAI-3(GenBank accession number:AF495883, AF515834, AY118086 and AY129303,respectively)encoded proteins with 353, 161, 137 and 72 animo acids respectively. Sj CAI protein contained six DNA-binding zinc fingers and showed some homology to gastrula zinc finger protein XLCGF48.2; proteins encoded by SjCA, SjCAI-2 and SjCAI-3 respectively contained N-glycosylation sites and phosphorylation sites. Conclusion Novel genes were obtained by immunoscreening Sj adult cDNA library.

Key words: Schistosoma japonicum, cercaria, cDNA library, immunoscreening, gene, sequence analysis