[Gene synthesis, expression and characterization of egg protein IPSE of Schistosoma mansoni].
OBJECTIVE
To synthesize and express the gene of egg protein IPSE (IL-4-inducing principle of Schistosoma mansoni eggs) and evaluate its immunologic characteristics.


METHODS
The IPSE gene of S. mansoni was synthesized by overlapping PCR, and confirmed by DNA sequencing, The recombinant plasmid IPSE-pET32a(+) was constructed by inserting the gene of IPSE into expression vector pET32a(+) at the downstream of thioredoxin (Trx) coding sequence. The recombinant plasmid IPSE-pET32a(+) was transformed into E. coli BL21(DE3) and followed by expression of the protein induced by IPTG. Large-scale fusion protein was prepared and purified with Ni affinity chromatography gel under denaturing conditions. A small amount of soluble Trx-IPSE was obtained by dialyzing the fusion protein in a large volume of PBS. Western blotting was used to detect if the recombinant IPSE was recognized by the IgG antibody in the pooled patient sera of schistosomiasis japonica and its binding capacity to the non-specific IgE antibody in the sera of healthy persons.


RESULTS
DNA sequencing confirmed that the nucleotide sequence of synthesized IPSE gene was completely identical to the native one. SDS-PAGE showed that the recombinant plasmid IPSE/pET32a(+) expressed a fusion protein with an Mr 35700 after being induced by IPTG. The pure fusion protein Trx-IPSE reacted positively with the pooled sera of schistosomiasis patients under either denaturing or renaturing conditions. The protein Trx-IPSE also reacted with the nonspecific IgE in the sera of healthy persons.


CONCLUSIONS
The IPSE gene of Schistosoma mansoni has been synthesized, and the recombinant can react with natural antibody IgG against S. japonicum and non-specifically bind to IgE antibody.
Xie
Shu-ying
SY
Jiangxi Provincial Institute of Parasitic Diseases, Nanchang 330046, China.
Chen
Hong-gen
HG
Yu
Chuan-xin
CX
Yin
Xu-ren
XR
Hua
Wan-quan
WQ
Zeng
Xiao-jun
XJ
Liang
You-sheng
YS
Gao
Qi
Q
D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood / Q000276:immunology; D001483:Base Sequence; D004527:Egg Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology*; D015801:Helminth Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008969:Molecular Sequence Data; D012550:Schistosoma mansoni / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D017422:Sequence Analysis, DNA
D000909:Antibodies, Helminth; D004527:Egg Proteins; D015801:Helminth Proteins; C474807:IPSE protein, Schistosoma mansoni; D007073:Immunoglobulin E