[Identification of early diagnostic molecules in soluble egg antigen of Schistosoma japonicum by MASS].
OBJECTIVE
To identify the molecules of soluble egg antigen (SEA) for early diagnosis of Schistosoma japonicum infection by two-dimensional electrophoresis (2-DE), immunoblotting and liquid chromatography with tandem mass spectrometry (LC-MS/MS).


METHODS
The 2-DE of SEA was executed through first direction isoelectric focusing (IEF) in immobilized pH gradient gel 3-10 (IPG3-10) and second direction SDS-PAGE. The protein dots of SEA on the SDS-PAGE gel were transferred to nitrocellulose membrane. These nitrocellulose membranes were responded to the sera of healthy, sera of mice at 1 week, 2 weeks and 6 weeks post-infection respectively, then the membrane color was developed with the second antibody of HRP labeled goat anti -mouse IgG conjugate and substrate DAB. The protein dots recognized by sera of mice in the early stage of schistosome infection were identified by LC-MS/MS.


RESULTS
After matching and analyzing the Western blot patterns of SEA responding to acute infection sera (1 week and 2 weeks post-infection), chronic infection sera (6 weeks post-infection) and healthy sera by PDQuest 1.0 software, two protein dots were found to be recognized by sera of mice at 1 week, 2 weeks and 6 weeks post-infection, and three protein dots were only recognized by the sera of mice at 6 weeks post-infection, no protein dot was recognized by healthy mouse sera. The data of LC-MS/MS showed that the two protein molecules recognized by the sera of mice with schistosome infection in the early stage were heat shock protein 70 (HSP70) and 78 kDa glucose-regulated protein (Grp78/Bip) respectively.


CONCLUSIONS
The results of this study preliminarily indicate that HSP70 and Grp78 in SEA have early diagnostic value for S. japonicum infection.
Jiangsu Institute of Parasitic Diseases, Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health, Wuxi 214064, China.
Jie
J
Wang
Li-Jun
LJ
Song
Wei
W
He
Xu-Ren
XR
Yin
Chun-Yan
CY
Qian
Wei
W
Zhang
Yong-Liang
YL
Xu
Guo-Qun
GQ
Cao
Xue-Dan
XD
Ke
Chuan-Xin
CX
Yu
D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry / Q000276:immunology*; D002853:Chromatography, Liquid; D000091342:Endoplasmic Reticulum Chaperone BiP; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology; D006360:Heat-Shock Proteins / Q000276:immunology; D051379:Mice; D010063:Ovum / Q000276:immunology*; D012549:Schistosoma japonicum / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000175:diagnosis*; D012995:Solubility; D053719:Tandem Mass Spectrometry
D000947:Antigens, Helminth; D000091342:Endoplasmic Reticulum Chaperone BiP; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C000717248:Hspa5 protein, mouse