[Identification of the SjARG novel gene and study on its protective potential as a vaccine]

To recognize and identify the arginase (ARG) gene of Schistosoma japonicum(Sj), and to study its protection potential as a vaccine.

The 5'-end of the ARG gene from the Sj cercariae cDNA library was amplified by nested-PCR and the sequence was identified by bioinformatics. The complete coding sequence(CDS) was cloned into pET30a (+) vector, and a recombinant SjARG protein (rSjARG) was expressed, purified and used to raise antibodies. ARG's activity as an enzyme was tested by ornithine-ninhydrin reaction. Western blotting was used to compare the immunologic characteristics of rSjARG with that of the native one in Sj adult worm. Indirect immunofluorescence assay was used to immunolocalize it. For evaluating the protection potential of rSjARG, mice were immunized by the recombinant protein and challenged by cercariae of S japonicum.

The CDS length of the SjARG novel gene was identified as 1095bp rSjARG showed enzyme activity and the same immunologic characteristics with the native arginase in adult worm. SjARG located in the genital organ and gut of both sexes. The worm reduction rate and egg reduction rate in rSjARG group were 55.8% and 48.8% respectively, higher than that of the rSj26GST group (28.6% and 6.89% respectively).

SjARG gene was identified, which shows a higher protection than the Sj26GST.