title: Opisthorchis viverrini: evaluation of 28 kDa glutathione S-transferase as diagnostic tool in human opisthorchiasis.
abstract: The liver fluke Opisthorchis viverrini is the agent of human opisthorchiasis in Thailand with a high prevalence observed in the rural population of north and northeastern regions of the country. A focus of research has therefore been the development of diagnostic tools to indicate infection by this parasite. In the present study, a 28 kDa glutathione S-transferase of O. viverrini (OV28GST), which is found in the excretion/secretion product of the parasite, was evaluated for its application in diagnosis of human opisthorchiasis. Bacterially expressed and functionally active rOV28GST was used in immunoblots and indirect ELISA to detect anti-OV28GST antibody in sera of infected individuals. Crude whole worm extract, sera of uninfected individuals and a rabbit anti-rOV28GST antiserum were used as controls in the assays while positivity for parasite DNA by PCR and egg count in faeces were used as primary indicators of infection. The results showed weak or absent reactivity of the infected sera to immunoblotted rOV28GST and no significant difference in absorbance values when compared to uninfected sera in ELISA. In addition, a glutathione capture ELISA which was performed to test for circulating OV28GST in human and hamster sera showed negative results. In conclusion, OV28GST is not applicable as a diagnostic tool in established infections due to low specific antibody titre and abundance as circulating antigen.
authors.affiliation: Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Rangsit Campus, 99 Moo 18, Pathumthani 12121, Thailand.
authors.forename: Veerachai
authors.initials: V
authors.lastname: Eursitthichai
authors.forename: Vithoon
authors.initials: V
authors.lastname: Viyanant
authors.forename: Smarn
authors.initials: S
authors.lastname: Tesana
authors.forename: Paiboon
authors.initials: P
authors.lastname: Sithithaworn
authors.forename: Nanthawat
authors.initials: N
authors.lastname: Kosa
authors.forename: Rudi
authors.initials: R
authors.lastname: Grams
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000276:immunology*; D015153:Blotting, Western / Q000379:methods; D018509:DNA, Helminth / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005243:Feces / Q000469:parasitology; D005260:Female; D005982:Glutathione Transferase / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009889:Opisthorchiasis / Q000175:diagnosis*; D009891:Opisthorchis / Q000276:immunology*; D010270:Parasite Egg Count; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013785:Thailand
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D018509:DNA, Helminth; D005982:Glutathione Transferase