Mapping of the antigenic determinants of the T. cruzi kinetoplastid membrane protein-11. Identification of a linear epitope specifically recognized by human Chagasic sera.

The high variability among strains and isolates of Trypanosoma cruzi and the existence of shared antigenic determinants with other pathogens, particularly with members of the Leishmania genus make difficult the specific diagnosis of Chagas' disease. The data reported in this paper show that the T. cruzi KMP11 protein is an immunodominant antigen highly recognized by the sera from chagasic and leishmaniasis patients. By the use of amino- and carboxyl-terminal truncated KMP11 recombinant proteins and synthetic peptides, evidence is provided that while the sera from chagasic patients recognize linear peptides the sera from patients with visceral leishmaniasis must be predominantly directed against conformational epitopes. We found that a particular linear determinant, located in the carboxyl-terminal region of the protein, is recognized with high specificity and sensitivity only by sera from Chagas' disease patients, suggesting it could be a good candidate for differential serodiagnosis of Chagas' disease.