Identification of a candidate vaccine peptide on the 37 kDa Schistosoma mansoni GAPDH

A previous study performed in adolescents living in an area endemic for Sch istosoma mansoni in Brazil has shown that a 37 kDa schistosome surface anti gen is a selective target for antibodies in sera from those who were resist ant to reinfection. This antigen was shown by molecular cloning to be the s chistosome GAPDH. The aim of the present work was to assess whether peptide s corresponding to GAPDH antigenic determinants could be used in a subunit vaccine. Five B cell and two T cell epitopic regions were identified on Sm3 7-GAPDH. One of the B cell determinants (Sm37-5, aa 268-289) is highly anti genic in human infections and antibody reactivity toward this determinant i s associated with resistance to reinfection. Mice and rats immunized with S m37-5 were partially protected against a challenge infection, indicating th at this peptide can induce protective immunity. Analysis of Sm37-5 amino ac id sequence indicated that this antigenic determinant is likely conserved a mong other pathogenic strains of schistosome (S. haematobium, S. intercalat um and S. japonicum), although it shows major amino acid differences with t he corresponding human GAPDH sequence. All together these results indicate that Sm37-5 should be considered as a candidate component for an anti-schis tosome subunit vaccine. (C) 2000 Elsevier Science Ltd. All rights reserved.