Detection of alpha-macroglobulin in the heart of mice infected with Trypanosoma cruzi.

The aim of this work was to investigate the presence of alpha-macroglobulin (AM) in the heart of mice during acute experimental Chagas' disease and to study its localization as related to the presence of the parasite and/or to their antigens. Frozen heart tissue sections obtained from Swiss albino male mice at different days postinfection with Trypanosoma cruzi were examined for triple immunofluorescence in response to parasite antigen (green), AM (red), and nuclei (blue) from both cells. AM was found in the heart of all the infected animals studied. Parasites were seen arranged in nests inside heart muscle cells. Usually, AM staining corresponded in position to parasite nests and to their antigens spread in large areas of the myocardium. The most intense staining of AM was observed at days 9 and 11 postinfection, when the highest tissue-infection level occurs. These observations relate the presence of AM to that of T. cruzi antigen in the same areas of the inflamed myocardium of the chagasic animals.