title: Schistosoma mekongi cathepsin B and its use in the development of an immunodiagnosis.
abstract: Schistosomiasis mekongi is one of the most important human parasitic diseases caused by Schistosoma mekongi in South-east Asia. The endemic area is the Mekong River sub-region from Laos to Cambodia. This parasite also infects dogs and pigs which are its alternative host species. Currently, the lack of reliable rapid diagnosis makes it difficult to monitor the infection and spreading of the disease. In this study, we screened the antigens of the parasite with sera of infected mice using Western blotting and identified proteins of interest with LC-MS/MS to obtain potential candidate proteins for diagnostic development. This assay yielded 2 immunoreactive bands at molecular masses of 31 and 22kDa. The 31kDa protein was the major band identified as cathepsin B, and its gene was cloned to obtain a full cDNA sequence (SmekCatB). The cDNA consisted of 1123bp and its longest reading frame encoded for 342 amino acids with some putative post translation modifications. The recombinant SmekCatB (rSmekCatB) with hexahistidine tag at the C-terminus was expressed in Escherichia coli and purified by Ni-NTA resin under denaturing conditions. The rSmekCatB reacted with sera of S. mekongi-infected mice. Indirect ELISA using rSmekCatB as the antigen to detect mouse antibodies, revealed a sensitivity of 91.67% for schistosomiasis mekongi and the specificity of 100%. Our data suggested that SmekCatB is one of the most promising parasitic antigens that could be used for the diagnosis of S. mekongi infection.
authors.affiliation: Faculty of Animal Sciences and Agricultural Technology, Silpakorn University, Phetchaburi Campus, Cha-am, Phetchaburi 76120, Thailand.
authors.forename: Manaw
authors.initials: M
authors.lastname: Sangfuang
authors.affiliation: Applied Malacology Unit, Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Yupa
authors.initials: Y
authors.lastname: Chusongsang
authors.affiliation: Applied Malacology Unit, Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Yanin
authors.initials: Y
authors.lastname: Limpanont
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd, Ratchathewi, Bangkok 10400, Thailand; Center of Excellence for Shrimp Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Rapeepun
authors.initials: R
authors.lastname: Vanichviriyakit
authors.affiliation: Mahidol University, Nakhonsawan Campus, Nakhonsawan 60130, Thailand.
authors.forename: Charoonroj
authors.initials: C
authors.lastname: Chotwiwatthanakun
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Rd, Ratchathewi, Bangkok 10400, Thailand; Faculty of Allied Health Sciences, Burapha University, Bangsaen, Chonburi 20131, Thailand.
authors.forename: Prasert
authors.initials: P
authors.lastname: Sobhon
authors.affiliation: Faculty of Animal Sciences and Agricultural Technology, Silpakorn University, Phetchaburi Campus, Cha-am, Phetchaburi 76120, Thailand. Electronic address: jnnarin@hotmail.com.
authors.forename: Narin
authors.initials: N
authors.lastname: Preyavichyapugdee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D002160:Cambodia / Q000453:epidemiology; D002401:Cathepsin B / Q000235:genetics / Q000276:immunology*; D007159:Immunologic Tests / Q000592:standards; D007812:Laos / Q000453:epidemiology; D051379:Mice; D012547:Schistosoma / Q000276:immunology*; D012552:Schistosomiasis / Q000175:diagnosis* / Q000453:epidemiology; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry
chemical_list: D000947:Antigens, Helminth; D002401:Cathepsin B
keywords: Cathepsin B (EC 3.4.22.1); Schistosoma mekongi; Serodiagnosis