PROTECTIVE IMMUNITY INDUCED BY A RECOMBINANT ANTIGEN RSJ06868 OF SCHIISTOSOMA JAPONICUM

To express the hypotheticial protein SJCHGC068068(gene was named as Sj06868) of Schistosoma japonicum(S.japonicum),and evaluate immune efficacy of the recombinant antigen in mice against Schistosomiasis,the 46-438 nt of Sj06868 was amplified by PCR from 7 d or 14 d Schistosomula.BLASTn analysis revealed that there were no conserved regions and motifs in the derived protein and no similar sequences of other species.This gene was subsequently cloned into the expression vector pET32a and expressed in E.coli Rosetta(DE3).The recombinant protein rSj068068 was a 36 kDa fusion protein,which could be recognized in Western blot by S.japonicum-infected rabbit sera.The purified recombinant protein was used to vaccinate BALB/c mice with ESSAI ISA 206 CELL as adjuvant.Worm reductions of 31.63% and 29.19%,and hepatic egg reductions of 55.63% and 56.27% were recorded in immunized group comparing with PBS and adjuvant control groups,respectively.There was significant increase of total IgG antibody response against rSj068068 in vaccinated group before challenge and control groups after challenge.These results indicated that Sj068068 was a peculiar gene of S.japonicum and highly expressed in schistosomula,and the recombinant protein has good potential for further studies on vaccine development and diagnosis.