ANALYSIS OF ANTI-TRYPANOSOMA CRUZI ANTIBODY ISOTYPE SPECIFICITIES BY WESTERN-BLOT IN SERA FROM PATIENTS WITH DIFFERENT FORMS OF CHAGAS-DISEASE

Infection of humans with Trypanosoma cruzi leads to either a lifelong asymptomatic infection or to symptomatic presentations such as cardiom yopathy, mega-syndromes, or both. The reasons for the different clinic al manifestations are not understood. We have previously studied a gro up of chronically infected individuals with different clinical forms o f Chagas' disease and found that the levels of some anti-T. cruzi anti body isotypes, analyzed by enzyme-linked immunosorbent assay, differed among patients with different clinical presentations. We have expande d these studies to examine the antigen specificity of these patients' IgG1, 2, 3, IgM, and IgA by western blot. We observed that binding of particular antigens by some antibody isotypes were more prevalent in s ome clinical groups as compared to others. For example, IgG3 from 13 o f 19 (68%) individuals with digestive manifestations bound a 68-kDa an tigen, but only 3 of 31 (9%) individuals with cardiac involvement dete cted this same moiety. We also found that, regardless of the clinical group, the profiles of antigens recognized by each antibody isotype di ffers dramatically from the profiles recognized by each other isotype. Together with our previous observations demonstrating that the levels of anti-parasite antibody isotypes correlates with the clinical form, these data suggest that overall anti-T. cruzi antibody reactivities m ay indeed be skewed toward different antigens in individuals with diff erent clinical presentations.