[Isolation and expression of recombinant diagnostic antigen gene of Schistosoma japonicum].

The sera of patients with chronic infection of Schistosoma japonicum (Sj) were used for screening the cDNA expression library constructed from Sj adult worm, and an antigen-positive clone Sjgt4 which expressed an 148 KD fusion protein was identified. The inserted Sj cDNA fragment was amplified by PCR and subcloned into the vector pGEX with high level of expression. A positive clone SjpG5 which expressed a fusion protein with a molecular weight of 58 KD was obtained. When the fusion protein was used for detection of Sj patients' sera by Western blot, 24 out of 25 sera were positive, a positive rate of 96%.