Abstract

We have stud ed in vitro proliferation in duced by soluble antigenic fractions of T. cruzi epimastigotes and trypomastigotes, as well as their regulatory effect on the proliferative response to PPD. Both crude extracts of the parasite as well as bands from Western blots of soluble epimastigotes and trypomastigotes anti gens were tested. Crude extracts elicited higher proliferation in mononuclear cells from patients with chagasic cardiomyopathy (CDM) than in those from patients with no evi dence of car diac pathoogy (INF). Fractionated antigens induced a lower proliferative response, in intensity as well as in frequency, than the crude extracts. With the soluble antigenic fractions of epimastigotes, cells from CDM patients gave higher responses to low molecu lar weight (MW) bands (17 to 30 kDa), and from INF patients, to bands of in ter me di ate MW (31 to 62 kDa); this pattern was inverted with soluble antigenic fractions of trypomastigotes. The two crude preparations induced either up-regulation or down-regulation of the PPD response in variable numbers of patients from both groups. With fractionated antigens, down-regulation intensity was stronger in patients with out evi dence of heart disease, but frequency was greater in patients with Chagasic cardiomyopathy (CDM). Six bands of western-blot of soluble trypomastigote antigens (B1, 4-7, and 9) induced significant down-regulation in 100% of CDM patients. The up-regulation elicited by most bands of the antigenic fractions was significantly higher, and more frequent in patients with out heart pathology. Most bands of soluble trypomastigote anti gens (10/15; 66.6%) did not induce up-regulation in patients with cardiomyopathy. These data sug gest that differences in the clinical status of the two groups may reflect the recognition of different groups of antigens to gether with variations in the nature of the regulatory response