Triose-phosphate isomerase is an important candidate for schistosoma antigens. An 800 bp DNA fragment was amplified by RT-PCR from adult Schistosoma japonicum mRNA. Sequence analysis revealed that this fragment contained S. japonicum (Chinese strain) triose-phosphate isomerase gene. Then this gene was cloned into the expression vector pGEX-4T and subsequently expressed in E. coli. The recombinant GST-fusion protein was purified by glutathione agarose affinity chromatography. Its molecular weight was determined to be 54 kD. The yield of expression was around 30 mg/L E. coli culture. Western blotting showed that the recombinant protein had good antigenicity which could be helpful for the making of anti-S. japonicum multi-valent recombinant vaccine.
A 600 bp DNA fragment was amplified by PCR, from an adult Schistosoma japonicum cDNA library. Sequence analysis revealed that this fragment containedthe S. japonicum Chinese Mainland strain fatty acid binding protein (Sj-14FABPc) gene. This gene was then cloned into the expression vector pGEX-2T, and subsequently expressed in Escherichia coli. The recombinant GST-fusion protein could be purified by glutathione agarose affinity chromatography. Its molecular weight was about 41 kD. The yield of expression was around 25 mg/L E. coli culture. The immunological test suggested that the recombinant protein had good antigenicity, and could be developed into a new vaccine molecule of S. japonicum.
The gene of the 28 kD glutathione S-transferase (GST) from the Chinese strain of Schistosoma japonicum had been expressed in the silkworm (Bombyx mori) cells and larvae by Bombyx mori nuclear polyhedrosis virus (BmNPV) vector which had been modified. The GST gene was inserted into the right position of the BmNPV genome as identified by Southern hybridization. The product was a 28 kD protein, had GST activity and antigenicity. The yield in BmN cells (1x10(6) cells/ml) was 0.77 mg and more than 5 mg in a silkworm larvae. All the results showed that it is possible to develop the GST expressed in the silkworm larvae to a new kind of genetic engineered schistosomiasis vaccine.
