[Cloning, expression and immune function analysis of a gene encoding inositol monophosphate in Schistosoma japonicum]

To clone and express a full-length cDNA encoding inositol monophosphate of Schistosoma japonicum (SjIM), and to access its immunoprotection in BALB/c mice for schistosomisis.

A full-length cDNA encoding the S. japonicum inositol monophosphate was isolated from 42 d schistosomes cDNAs. The expression profiles in different developmental stages were detected by real-time quantitative RT-PCR. The open reading frame (ORF) was subcloned into a pET28a(+) vector and transformed into BL21 and the recombinant protein was induced by IPTG. The immune characters of the purified recombinant protein were analyzed by Western blotting and immunoprotection in BALB/c mice.

Bioinformatics analysis indicated that SjIM had an ORF of 834 base pairs that encoded 278 amino acids. Real-time quantitative RT-PCR analysis revealed that SjIM was upregulated in 35-day-old schistosomes, while the expression level in females was higher than that in male worms in 42nd day. Western blotting showed that the recombinant SjIM was immunogenic. An immunoprotection experiment in BALB/c mice showed that vaccination with recombinant SjIM could induce 48.76% and 41.29% reductions in the numbers of worms and eggs in the liver, respectively.

The gene of SjIM is obtained from schistosomes cDNAs and the recombinant SjIM protein is induced successfully in E. coli. These aforementioned results demonstrate that the recombinant SjIM cand induce partial protection against schistosomiasis in BALB/c mice.