OBJECTIVEIn order to develop the diagnostic genechip for specific detection of Schistosoma japonicum (Chinese mainland strain).

METHODSProbe and primers were designed based on the Schistosoma japonicum 5D gene encoding an immunogenic miracidial antigen. The probe for the conservative and specific gene sequence was spotted onto the specially treated glass slides by pin-based spotting robot Pixsys 5500 and was employed to make genechips. A polymerase chain reaction (PCR) protocol was designed to effectively amplify the 5D gene fragment containing the probe sequence from cercaria, egg, adult worm and infected Oncomelania DNA as well as other flukes DNA, respectively. After 35 cycles by PCR, the products were then labeled with fluorescent Cy3-labeled primer, using dissymmetrical PCR. The labeled PCR products of the target genes were hybridized to the diagnostic genechips for detection of Schistosoma japonicum and a fluorescent scanner (ScanArray 3000) was used to observe and record the hybridization signals.

RESULTSThe result obtained from the study showed that a 262 bp DNA fragment was amplified from cercaria, egg and adult worm with the designed primers and enable the genechip be applied to detect a single cercaria, egg and adult worm. When the genechip was used to detect Clonorchis sinensis, Fasciolopsis busk, and Paragonimus westermani DNA, the results showed negative, indicating that the genechip had good specificity.

CONCLUSIONThe genchip technique for detection of Schistosoma japonicum was established successfully and having the characteristics of high sensitivity and specificity.