Abstract: 　Objective To clone and analyze novel antigen molecules of Schistosoma japonicum (Sj), and to provide effective vaccine candidate antigens against schistosomiasis japonica. Methods Sj adult cDNA library was screened using sera of mice infected with Trichinella spiralis (Ts) and the inserts of positive clones were specifically amplified by PCR. The positive clones were sequenced and the sequence data were analyzed using Nucleotide BLAST software of NCBI and Expert Protein Analysis System of Swiss Institute of Bioinformatics. Results Nine positive clones were obtained after three rounds of immunoscreening. The size of these inserts ranged from 0.6 kb to 2.1 kb. Among five novel genes, Sj Ts1, Sj Ts3 and Sj Ts5 (GenBank accession number: AY005816, AF299080 and AY024352,respectively) encode transmembrane proteins with 83, 83 and 233 amino acids, respectively. Sj Ts1 protein predicted contains one possible transmembrance helix, one N myristoylation site, two phosphorylation sites for protein kinase C and one for tyrosine kinase, Sj Ts3 protein contains two possible transmembrance helices and one casein kinaseⅡphosphorylation site, whereas Sj Ts5 protein has five possible transmembrance helices, one N glycosylation site, one N myristoylation site, two phosphorylation sites for cAMP and cGMP dependent protein kinase and four for protein kinase C and one for casein kinase Ⅱ. Conclusion Three novel genes encoding three transmembrane proteins might be developed as new vaccine candidates against Sj infection.

Key words: Schistosoma japonicum, Trichinella spiralis, antigen molecule, clone, sequence analysis