[Prokaryotic expression of gene encoding Schistosoma japonicum SjE16 and its potential application in immunodiagnosis].
OBJECTIVE
To sub-clone and express the gene encoding Schistosoma japonicum calcium-binding protein (SjE16) and study its immunological response.


METHODS
The specific primers were designed according to the expressed sequence tags (ESTs) sequence, which was used for amplification of the encoding sequence from the cDNA clone containing SjE16. The gene was subcloned into pGEX4T-1 plasmid and expressed. The rSjE16 was tested for its immunological response by ELISA.


RESULTS
The gene encoding Schistosoma japonicum SjE16 was cloned and expressed successfully. The immunogenicity and diagnostic potential of rSjE16 were investigated. It was demonstrated by immunoassay in rabbits that the specificity and sensitivity of the test were 94.1% (16/17) and 88.2% (15/17), respectively, and the level of antibody titer of the untreated group reached a peak at 9-11 wk post infection and maintained high at least for 21 wk post infection, while the antibody level in the treated group rapidly decreased to pre-infection level in 11 wk after treatment. In human, the specificity of the test was 98.3% (57/58); the sensitivity of acute and chronic patient serum assay was 85.5% (53/62) and 70.2% (40/57), respectively.


CONCLUSIONS
The recombinant protein of SjE16 (rSjE16) was acquired. It can be recognized by the sera from schistosomiasis patients, and the level of antibodies decreased quickly after treatment in experimental rabbits, which implicates the potential value for the evaluation of chemotherapy and detection of active infection.
Wang
Zhao-jun
ZJ
Department of Pathogenic Biology, Shanghai Second Medical University, Shanghai 200025.
Hu
Wei
W
Shen
Da-kang
DK
Wu
Xiao-wen
XW
Wang
Ju-jun
JJ
Han
Ze-guang
ZG
Xue
Chun-liang
CL
D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D002135:Calcium-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D020224:Expressed Sequence Tags; D007159:Immunologic Tests; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology*; D012549:Schistosoma japonicum / Q000235:genetics / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000175:diagnosis; D012680:Sensitivity and Specificity
D000909:Antibodies, Helminth; D002135:Calcium-Binding Proteins; D011993:Recombinant Fusion Proteins