title: A novel immunodiagnostic assay to detect serum antibody response against selected soluble egg antigen fractions from Schistosoma japonicum.
abstract: BACKGROUND
  Schistosomiasis japonica remains a real threat to public health in China. The currently used immunodiagnostic assays are sensitive and have a certain degree of specificity, however, they all use complex crude antigens, are based on detection of schistosome-specific antibodies, and have been shown to cross-react with other parasitic diseases. Therefore, these assays cannot be used to evaluate chemotherapy efficacy. The development of highly sensitive and highly specific immunodiagnostic techniques that can monitor the decline of antibodies specific for S. japonica will be extremely valuable as part of the ongoing strategy to control schistosomiasis in endemic areas. Here we report on the identification of unique fraction antigens of soluble egg antigen (SEA) to which the antibodies disappear 7 weeks after effective treatment. Furthermore, we use these SEA fractions to develop a modified assay with both high sensitivity and specificity.
  
  
  RESULTS
  SEA of S. japonicum was fractionated by electrophoresis using 7.5% SDS-PAGE under non-reducing conditions. The SEA fraction antigens to which antibodies were decreased soon after treatment were collected and used as the detection antigens to establish the FA-ELISA. Sera from patients with acute and chronic schistosomiasis infection, healthy people, and those with other parasitic diseases, were used to evaluate their sensitivity and specificity. Furthermore, sera from patients with chronic schistosomiasis infection were evaluated before and after treatment at different time points to evaluate their chemotherapeutic efficacy.
  
  
  CONCLUSIONS
  We demonstrated that this novel FA-ELISA provided high sensitivity and specificity, with very low cross-reactivity, and can serve as an effective tool to determine the efficacy of chemotherapy against S. japonicum.
authors.affiliation: Key Laboratory on Technology for Parasitic Diseases Prevention and Control, Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, People's Republic of China. yczhu2006@yahoo.com.cn
authors.forename: Yinchang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Wanquan
authors.initials: W
authors.lastname: Hua
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Dai
authors.forename: Song
authors.initials: S
authors.lastname: Zhao
authors.forename: Jianxia
authors.initials: J
authors.lastname: Tang
authors.forename: Shixia
authors.initials: S
authors.lastname: Wang
authors.forename: Shan
authors.initials: S
authors.lastname: Lu
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D000917:Antibody Formation / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology; D000947:Antigens, Helminth / Q000097:blood / Q000276:immunology*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007159:Immunologic Tests / Q000379:methods*; D010063:Ovum / Q000276:immunology*; D011817:Rabbits; D012549:Schistosoma japonicum / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000175:diagnosis / Q000276:immunology / Q000469:parasitology; D012680:Sensitivity and Specificity; D044967:Serum / Q000276:immunology* / Q000469:parasitology*; D012995:Solubility; D013347:Subcellular Fractions / Q000276:immunology
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth