Suppression of antibody responses in humans infected with Trypanosoma cruzi

Peripheral blood leukocytes from patients serologically positive for Chagas' disease were examined for their ability to respond to heterologous antigens in vitro. It was found that mononuclear cells from chagasic patients had greatly reduced ability to respond to sheep erythrocytes (SRBC) as compared with peripheral blood mononuclear cells (PBMC) from control subjects. The reduction in anti-SRBC antibody activity was independent of antigen dose and was not a result of differences in antibody response kinetics. Depletion of plastic-adherent result of differences in antibody response kinetics. Depletion of plastic-adherent cells from the PBMC of patients did not affect the suppressed state of the nonadherent lymphocytes. No relationship was evident between the duration of Trypanosoma cruzi infection and the degree of humoral responsiveness.