Induction of heart alterations by immunization with subcellular fractions from Crithidia fasciculata

Presence of anti-Trypanosoma cruzi antibodies in the sera of mice with experimental autoimmune myocarditis

The existence of antigens shared in common by T. cruzi and heart muscle cells is suggested by the presence of antibodies binding to the parasite surface in the serum of mice with autoimmune myocarditis induced by immunization with syngenic heart antigens.

Longitudinal studies of the immune response of Colombian patients infected with Trypanosoma cruzi and T. rangeli

Two groups of patients were examined for anti-Trypanosoma cruzi antibodies by immunofluorescence and ELISA (i) inhabitants of the village and surrounding rural area of Tibu, Norte de Santander, Columbia (n = 327) and (ii) employees of the Empresa Colombiana de Petroleos (ECOPETROL, n = 849). The latter group had a lower rate of positive serology (12 as compared to 29%) but the distributions of antibody titres were very similar in the two groups. A total of 119 serum samples (37 village and 82 ECOPETROL, including 25 seronegative controls) were analysed for their ability to immunoprecipitate the 7 major polypeptides of T. cruzi trypomastigotes of Mr greater than 72 kDa. Although 10 sera from positive patients showed no immunoprecipitation, all of the remaining positive sera contained antibodies which reacted with the 150, 90 and 85 kDa polypeptides. When the T. cruzi immunofluorescence positive, immunoprecipitation negative sera were retested by ELISA using GP90, all were negative thus suggesting that the patients had had a misdiagnosed T. rangeli infection. The new diagnosis was confirmed by immunofluorescence and ELISA with T. rangeli epimastigotes. Longitudinal studies were carried out on 19 patients from the ECOPETROL group for up to 3.5 years. Five seropositive patients showed a change in their anti-trypomastigote immunoprecipitation profiles over this period; one by loss of a previously recognized high molecular weight band and four others by conversion from a negative to a positive immunoprecipitation profile. These latter patients presented initially with uncomplicated T. rangeli infection but then acquired a T. cruzi superinfection. These patients represent the nucleus of a group in which prospective studies will identify the effect of T. rangeli infection on the course of subsequent South American trypanosomiasis and Chagas' disease.

Immunoprotection of mice against Trypanosoma cruzi with a lyophilized flagellar fraction of the parasite plus adjuvant

The immunization with the flagellar (F) fraction from epimastigotes of Trypanosoma cruzi has been shown to protect mice against a challenge of bloodstream trypomastigotes of the parasite, both in terms of mortality and decrease in parasitemia. We have compared the immunoprotective properties of the fresh F fraction with those of a lyophilized F (LF) fraction, alone or together with Bordetella pertussis (Bp) as adjuvant. The best results were obtained with LF + Bp: after challenge with 1 X 10(3) metacyclic trypomastigotes, 100% of the mice immunized with LF + Bp survived, and 60% of them showed no signs of parasitemia. Only the animals in which patent parasitemia was demonstrated presented heart and muscle infiltrates.