ANTIGENICITY AND IMMUNOGENICITY OF P-30-DERIVED PEPTIDES IN EXPERIMENTAL-MODELS OF TOXOPLASMOSIS

P30, also referred to as SAG-1, is now recognized as a major Toxoplasm a gondii antigen potentially important for both diagnosis and immunopr ophylaxis of toxoplasmosis. By using predictive algorithms, five synth etic peptides (48-67, 82-102, 213-230, 238-256 and 279-285) derived fr om P30, were investigated for B- and T-cell determinants in mouse and rat experimental models. Antibody recognition appeared more broadly di stributed along the P30 sequence, whereas T-cell recognition was mainl y targeted on the 238-256 peptide. In the absence of any carrier prote in, this peptide induced a B- and T-cell immune response independent o f the route of immunization (oral route or subcutaneous injection). Th is peptide (238-256) induced multiple antibody isotypes. In contrast w ith the 238-256 peptide, the 48-67 peptide, either free or in the form of a multiple antigenic peptide (MAP) construct or the 279-295 peptid e, elicited antibodies associated with a TH2 response. This study repo rts for the first time the analysis of the antigenic and immunogenic p roperties of P30-derived peptides and are potentially useful for vacci nal strategies incorporating the P30 Toxoplasma gondii antigen.