A multi-epitope synthetic peptide and recombinant protein for the detection of antibodies to Trypanosoma cruzi in radioimmunoprecipitation-confirmed and consensus-positive sera

Peptide epitopes of Trypnaosoma cruzi have been identified through expressi on cloning. A tripeptide (2/D/E) containing three epitopes (TcD, TcE, PEP-2 ) was used in ELISA to detect antibodies to T. cruzi in 239 of 240 consensu s-positive sera and 41 of 42 sera confirmed positive by radioimmunoprecipit ation assay. The 1 discrepant consensus-positive serum was used to expressi on-clone a novel gene that contained a repeat sequence, A peptide correspon ding to this sequence, TcLo1.2, was specific for T. cruzi. This antigen det ected the discrepant consensus-positive serum and enhanced reactivity of lo w-positive sera in the tripeptide assay. A branched synthetic peptide, 2/D/ ELo1.2, or a linear recombinant, r2/D/E/Lo1.2, realized all of the diagnost ic features of the four epitopes, including the ability to boost reactivity of low-reactive sera. These studies show that peptides and recombinants co ntaining multiple repeat epitopes are powerful tools for developing assays for T. cruzi antibody detection and have direct application in blood screen ing.