Opisthorchis viverrini: Identification of a glycine–tyrosine rich eggshell protein and its potential as a diagnostic tool for human opisthorchiasis

• Published in: International journal for parasitology 2006-11, Vol.36 (13), p.1329-1339
• Main Authors: Ruangsittichai, Jiraporn, Viyanant, Vithoon, Vichasri-Grams, Suksiri, Sobhon, Prasert, Tesana, Smarn, Upatham, Edward Suchart, Hofmann, Annemarie, Korge, Günter, Grams, Rudi
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antigens, Helminth - genetics; Base Sequence; Biological and medical sciences; Cloning, Molecular; Cricetinae; DNA, Complementary - genetics; DNA, Helminth - genetics; Egg Proteins - analysis; Egg Proteins - genetics; Egg Proteins - immunology; Eggshell protein; Electrophoresis, Polyacrylamide Gel - methods; Enzyme-Linked Immunosorbent Assay - methods; Expression; Fishes - parasitology; Fundamental and applied biological sciences. Psychology; Gene Library; Glycine - analysis; Helminth Proteins - analysis; Helminth Proteins - genetics; Helminth Proteins - immunology; Humans; Invertebrates; Life cycle. Host-agent relationship. Pathogenesis; Localization; Mice; Molecular cloning; Molecular Sequence Data; Nemathelminthia. Plathelmintha; Opisthorchiasis - diagnosis; Opisthorchis - genetics; Opisthorchis - immunology; Opisthorchis viverrini; Protozoa; Rabbits; Sequence Analysis, DNA - methods; Serodiagnosis; Trematode; Tyrosine - analysis
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/j.ijpara.2006.06.012

A cDNA encoding a novel eggshell protein (OvESP) with high-glycine (49.2%) and -tyrosine (27.8%) content was cloned from the human liver fluke Opisthorchis viverrini. In the adult parasite, the RNA products of the OvESP gene are limited to the vitelline follicles. They have a size of 800 nucleotides and are already present in 2-week-old juveniles. Immune sera of hamsters, experimentally infected, and humans, naturally infected with O. viverrini, detect bacterially expressed recombinant OvESP (rOvESP). A rabbit anti-rOvESP antiserum only reacts with the shells of intrauterine eggs in tissue sections of the parasite. Comparison of rOvESP with the parasite’s excretion/secretion products as diagnostic tools for human opisthorchiasis shows a higher sensitivity (0.82–0.48) and specificity (0.97–0.91) of the recombinant protein in the ELISA technique. But the observed weak cross-reactivity of immune sera from mice infected with Schistosoma mansoni, Schistosoma mekongi, and Fasciola gigantica in Western blots of rOvESP indicates that the diagnostic quality of this protein might be compromised if infections by other trematodes are present.