[Cloning, expression and immuno-protection analysis of a gene encoding troponin T of Schistosoma japonicum (SjTnT)]. OBJECTIVE
 To clone cDNA encoding troponin T of Schistosoma japonicum (SjTnT), and evaluate the protective efficacy induced by recombinant SjTnT in BALB/c mice against S. japonicum challenge infection.


 The SjTnT gene was amplified from 28-day-schistosome cDNAs by PCR and then subcloned into pET28a(+).  The recombinant SjTnT protein (rSjTnT) was expressed in Escherichia coli BL21 (DE3) cells.  The serum specific to rSjTnT was prepared by immunized BALB/c mice with the recombinant antigen, and the immunogenicity of rSjTnT was detected by Western blotting and ELISA.  The immuno-protective efficacy induced by rSjTnT in BALB/c mice was evaluated according to the reduction in worm and egg counts.


 The cDNA encoding SjTnT was successfully cloned and expressed in E. coli.  Western blotting showed that rSjTnT had a good immunogenicity.  The high level of specific IgG antibodies was detected, and 33.89% worm reduction and 43.94% liver egg reduction were obtained in mice vaccinated with rSjTnT combined with Seppic 206 adjuvant compared with those in the adjuvant control group.


 CONCLUSIONS
 rSjTnT could induce partial immuno-protection against S. japonicum infection in BALB/c mice.  This study provided a basic for understanding the biological function of SjTnT.
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