The Screening And Identification Of Diagnosis Targets For Schistosomiasis Based On The Functional Genomics Of Schistosoma Japonicum

Schistosomiasis caused by Schistosome japonicum remains a serious neglected tropical disease, ranking second only to malaria on the list of parasitic dieases with long history in the world. Diagnosis is the only way to determine infection rate and infection degree for its central role in the control of schistosomiasis. While the treatment and control of schistosomiasis depends almost exclusively on praziquantel, most immunodiagnostic assays currently applied in China indicated that the schistosome-specific antibody level has a tendency to rise for at least1year after cure and in many cases much longer. There is evidence that chemotherapy with praziquantel could lead to variations in parasite antibody levels and host immune responses. Hence, knowledge of the effects of praziquantel on schistosome soluble antigens components is essential for diagnosis and chemotherapy efficacy, which is also a useful complementary way to the surveillance of schistosomiasis in epidemic area. Furthermore, such knowledge is able to facilitate understanding of egg-induced pathology during schistosomiasis. Considering above characters of schistosomiasis, screening and identification of diagnosis and chemotherapy efficacy targets for schistosomiasis based on the functional genomics Schistosoma japonicum were conducted. The main results are as follows:1. Immunomic analysis of Schistosoma japonicum soluble egg and worm antigensImmunomic analysis of Schistosoma japonicum soluble egg and worm antigens recognized by pooled serum of pre-and post-treatment with praziquantel were performed by combination of2-dimensional electrophoresis and western blotting techniques. Soluble proteins which were extracted from eggs and adult worms of Schistosoma japonicum were separated by2-dimensional electrophoresis. Proteins were electrotransferred from2-dimensional gels to Hybond-C Nitrocellulose membranes which were subsequently probed using pre-treatment and post-treatment serum samples. Eighty-four spots detected in soluble egg antigens were subjected to mass spectrometry and67of them were identified successfully. However soluble worm antigens showed no significant reaction with serum samples.2. The prediction of epitope peptides in Schistosoma japonicum functional genomics55,125epitope peptides from10,411proteins of Schistosoma japonicum were predicted with software BepiPred.3. Cloning, expression and preliminary evaluation of diagnosis candidate proteins for schistosomiasisWe integrated the information of immunomic analysis and B-cell epitope peptides prediction to analysis diagnosis candidate proteins. Four individual schistosome proteins (Sj HSP60, Sj RPL18a, Sj Aminopeptidase and Sj Integrin) were amplified and subcloned into pET28-a or pGEX-4T-1vector plasmids respectively. The recombinant proteins were expressed under the induction of IPTG in E.coli BL21(DE3). Of these, serological evaluation of Sj HSP60showed the prospect for schistosomiasis diagnosis. The results showed that Sj HSP60could distinguish pooled patient serum from normal control.