Sequence Analysis of a Fasciola Hepatica Glutathione S-Transferase cDNA Clone

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  • Laboratory of Parasite Immunology and Pathology, Department of Pathology, and Laboratory of Molecular Biology, Department of Biochemistry, University of Puerto Rico School of Medicine, San Juan, Puerto Rico

A λgt11 Fasciola hepatica cDNA library was previously constructed from poly(A)+ RNA extracted from adult worms. A cDNA encoding F. hepatica glutathione S-transferase (FhGST) (GenBank Accession Number M93434) was cloned by screening the library with a rabbit anti-FhGST antiserum. The FhGSTs are suspected to be early developmentally expressed-proteins that act as potent immunogens and may be useful as candidate vaccines against the parasite. The cDNA was sequenced and contains 627 translated bases encoding a 24,211-Dalton polypeptide with 209 amino acids and an isoelectric point (pI) of 5.324. This polypeptide has significant homology with 26-kD GSTs from Schistosoma mansoni (57.42%) and S. japonicum (57.14%). In addition, we have identified the predicted T cell epitopes in the FhGST protein molecule.