Immunoblotting with trypomastigote excreted-secreted antigens (TESA blot) of Trypanosoma cruzi was evaluated as a method for diagnosis of chronic and acute phases as well as congenital (in newborn children) Chagas' disease. Serum samples from acute-phase and congenital infections were considered to be positive when they reacted with ladder-like bands of 130- to 200-kDa antigens, recognized by immunoglobulin M (IgM) and IgG antibodies, while IgG from chronic-phase sera recognized a broad band antigen of 150 to 160 kDa. Nonchagasic sera were not reactive to these antigens. The study was carried out on 512 patients, 111 of whom were nonchagasic but included cases of leishmaniasis or other pathologies, and 401 chagasic patients. The latter group comprised 361 chronic cases, 36 acute cases, and 4 congenital cases in newborn children. Among the chronic cases, 256 were from areas in which T. cruzi is endemic but which differed widely in the pathogenic expression of T. cruzi infection and in parasitemia levels. These patients at the same time showed a broad range of low, medium, and high reactivity to conventional enzyme-linked immunosorbent assays and indirect immunofluorescence serotests for Chagas' disease. For these reasons they may better represent the universe of chagasic patients than would a sample of highly reactive sera obtained from chagasic patients in a single area endemic for T. cruzi. All acute and congenital cases showed positivity in the IgM and IgG TESA blots, while chronic cases were 100% positive for IgG antibodies. In nonchagasic sera, including 30 cases of visceral and muco-cutaneous leishmaniasis, the specificity index was 1.000, and no cross-reactions were observed. The TESA blot thus seems to be useful as a sensitive and specific diagnostic assay in cases of suspected acute or congenital T. cruzi infection and as a general confirmatory test for conventional Chagas' disease serology.

The prolonged use of DIPY in this experimental model of CCC has reduced the rest myocardial perfusion defects, supporting the notion that those areas correspond to viable hypoperfused myocardium.

Our results clearly indicate the need to improve the diagnosis of Chagas' disease in blood banks by using new confirmatory diagnostic test(s). The TESA-blot, a new test with trypomastigote fractions of the T. cruzi Y strain, has made new approaches to the confirmation of Chagas' disease possible.

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An analysis of antibody recognition of Trypanosoma cruzi exoantigens by immunoblotting revealed a unique banding pattern that seems to be characteristic of each strain or isolate. Trypomastigote excreted-secreted antigens (TESA) present in supernatants of LLC-MK2 cells infected with 5 strains and 10 isolates of T. cruzi produced 13 different immunoblotting patterns. The same bands were observed when probed with acute-phase Chagas' disease serum or with serum from a rabbit immunized with the repetitive domain of T. cruzi transialidase recombinant protein (anti-shed acute-phase antigens). Three similar patterns were observed with TESA from 3 human isolates that probably belong to the same T. cruzi strain. When clone CL Brener, clone CL-14, and CL parental strain were analyzed, the same bands were observed, although they presented different biological behavior. These results suggest that immunoblotting analysis of TESA may be a useful tool for characterization of T. cruzi strains and isolates.

The present study analyzed serum samples from 111 male and female dogs of various ages from the municipality of Araguaína in the State of Tocantins, Brazil. Serological diagnosis of canine visceral leishmaniasis (CVL) was initially performed at the Central Laboratory (Laboratório Central -LACEN) of Araguaína, resulting in 61 positive samples by an indirect immunofluorescence assay (IIFA) (≥1:40) and 50 non-reactive samples. The same samples were analyzed at the São Paulo Institute of Tropical Medicine (Instituto de Medicina Tropical de São Paulo -IMTSP) by an enzymelinked-immunosorbent assay (ELISA), resulting in 57 positive samples (51.35%) and 54 negative samples (48.64%). The Kappa coefficient of agreement between the tests was 0.74. The serum samples were also subjected to a diagnostic assay for Trypanosoma cruzi (Trypomastigote Excreted/Secreted Antigens -TESA-blot) that detected five suspect animals; three of those animals were positive for leishmaniasis by ELISA but negative by IIFA. These findings suggest that the canine population of Araguaína may be simultaneously infected with Leishmania chagasi and T. cruzi. The results obtained demonstrate the difficulty of using serology to detect CVL, thus emphasizing the necessity for a reference test to diagnose CVL, particularly in regions where the infection is endemic.

During an infection the immune system produces pathogen-specific antibodies. These antibody repertoires become specific to the history of infections and represent a rich source of diagnostic markers. However, the specificities of these antibodies are mostly unknown. Here, using high-density peptide arrays we examined the human antibody repertoires of Chagas disease patients. Chagas disease is a neglected disease caused by Trypanosoma cruzi, a protozoan parasite that evades immune mediated elimination and mounts long-lasting chronic infections. We describe a proteome-wide search for antigens, characterised their linear epitopes, and show their reactivity on 71 individuals from diverse human populations. Using single-residue mutagenesis we revealed the core functional residues for 232 of these epitopes. Finally, we show the diagnostic performance of identified antigens on challenging samples. These datasets enable the study of the Chagas antibody repertoire at an unprecedented depth and granularity, while also providing a rich source of serological biomarkers.