- Vaccination of sheep against Fasciola hepatica with glutathione S-transferase. Identification and mapping of antibody epitopes on a three-dimensional model of the antigen. Sexton, J.L., Wilce, M.C., Colin, T., Wijffels, G.L., Salvatore, L., Feil, S., Parker, M.W., Spithill, T.W., Morrison, C.A. J. Immunol. (1994)