Delayed-type skin reactivity against a Trypanosoma cruzi antigen tuas elicited in 35.7per cent of the individuals living in the country of Mambai, state of Goiás, Brazil. The specificity of this skin reaction was shoum in 93 out of 94 (98.7%) chagasic patients, in whom the parasitemias were detected by xenodiagnosis. In these patients, however, the hemagglutination, immunofluorescence and complement fixation assays were positive in respectively, 100, 97.8 and 80.6 per cent. The relationship between the combined positive results by hemagglutination and immunofluorescence with that obtained with skin testings was 0.897, in the overall population in this study. The quantity of 50µg of protein in 100µl of the T12E antigen did not produce undesired effects, and did not shift the immunologic assays, when healthy volunteers were skin tested five times within 15-day intervals. Also, the potency of this antigen remained unaltered after 24 months at -10ºC.
T12E antigen; Delayed-type skin hypersensitivity; Chagas' disease