Monoclonal antibodies to stages of Trypanosoma cruzi: characterization and use for antigen detection.

Monoclonal antibodies to the amastigote and epimastigote stages of Trypanosoma cruzi were produced and characterized by immunoglobulin class and subclass. Of the 17 monoclonal antibodies, 14 were of the immunoglobulin M (IgM) class and 2 were of the IgG2 and 1 was of the IgG1 subclass of IgG. Five of the monoclonal antibodies recognized the antigens of amastigotes only, two recognized the antigens of epimastigotes only, and ten recognized an antigen(s) common to both stages of T. cruzi. By using an immunofluorescence test with monoclonal antibodies, it was possible to visually localize amastigote- or epimastigote-specific antigens and the antigens common to both. Antigens specific for epimastigotes were noted on the flagellum or in spots over the entire body of the parasite. The antigens common to both amastigotes and epimastigotes were on one of the extremities of the amastigotes and on the region of the flagellar pouch of the epimastigotes. Four of the monoclonal antibodies were capable of detecting T. cruzi antigen in serum from mice infected with the parasite and in the supernatant of infected cell cultures, suggesting that monoclonal antibodies may be useful for antigen isolation and diagnostic methods.