RESUMO
Trypanosoma cruzi, the agent of Chagas disease, is genetically classified into two major evolutionary lineages, T. cruzi I and T. cruzi II. In Southern American Cone countries it is T cruzi II which causes most cases of severe chronic Chagas disease. Contrary to this, we isolated T. cruzi I nested in endomyocardial biopsies of a chronic chagasic patient with end-stage heart failure. Our finding should alert clinicians to the possibility of severe Chagas disease in all regions where T. cruzi circulates, regardless of its lineage.
Assuntos
Cardiomiopatia Chagásica/parasitologia , Coração/parasitologia , Trypanosoma cruzi/genética , Animais , Biópsia/métodos , Baixo Débito Cardíaco/parasitologia , Doença Crônica , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético/genética , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Trypanosoma cruzi isolates from 23 acute chagasic patients from localities of Western Venezuela (state of Barinas) where Chagas' disease is endemic were typed using ribosomal and mini-exon gene markers. Results showed that isolates of the two major phylogenetic lineages, T. cruzi I and T. cruzi II, were isolated from these patients. Six isolates (26%) were typed as T. cruzi II and 17 (74%) as belonging to T. cruzi lineage I. Analysis of random amplified polymorphic DNA (RAPD) patterns confirmed these two groups of isolates, but did not disclose significant genetic intra-lineage polymorphism. Patients infected by both T. cruzi I or T. cruzi II showed different clinical profiles presenting highly variable signs and symptoms of acute phase of Chagas' disease ranging from totally asymptomatic to severe heart failure. The predominance of T. cruzi I human isolates in Venezuela allied to the higher prevalence of severe symptoms of Chagas' disease (heart failure) in patients infected by this lineage do not corroborate an innocuousness of T. cruzi I infection to humans. To our knowledge, this is the first study describing predominance of T. cruzi lineage I in a large number of acute chagasic patients with distinct and well-characterized clinical profiles.
Assuntos
Doença de Chagas/parasitologia , Trypanosoma cruzi/classificação , Doença Aguda , Adulto , Animais , Doença de Chagas/diagnóstico , Criança , Pré-Escolar , DNA de Protozoário/genética , Feminino , Marcadores Genéticos , Insuficiência Cardíaca/parasitologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Parasitologia/métodos , Polimorfismo Genético , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Trypomastigote forms of Trypanosoma cruzi excrete-secrete several molecules, which are immunodominant during the human infection. This complex antigenic mixture termed TESA (Trypomastigote Excreted-Secreted Antigens) presents a 150-160 kDa band that shows excellent specificity and sensitivity in Chagas' disease diagnosis by immunoblotting. Here we describe the isolation and the antigenic characterization of a recombinant peptide (TESA-1) containing a 10 kDa T. cruzi peptide that belongs to the 150-160 kDa TESA fraction. The clone was isolated by screening a T. cruzi genomic expression library with chagasic antibodies reactive to the 150-160 kDa band of TESA immunoblots. After expression, the recombinant peptide TESA-1 was purified and used to immunize rabbits. Anti-TESA-1 immunesera specifically recognized the 150-160 kDa fraction of TESA-blots from eight different T. cruzi strains. The TESA-1 peptide reacted with 82.2% of chagasic patient sera by immunoblotting, showing that it harbors most of the antigenic epitopes that account for the high reactivity of the 150-160 kDa band of TESA.
Assuntos
Antígenos de Protozoários/genética , Antígenos de Protozoários/isolamento & purificação , Epitopos Imunodominantes/genética , Epitopos Imunodominantes/isolamento & purificação , Trypanosoma cruzi/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Especificidade de Anticorpos , Antígenos de Protozoários/química , Western Blotting , Clonagem Molecular , Feminino , Soros Imunes/imunologia , Epitopos Imunodominantes/química , Peso Molecular , Coelhos , Sensibilidade e Especificidade , Trypanosoma cruzi/química , Trypanosoma cruzi/genéticaRESUMO
Reactivities of 4 lectins with intact trypomastigote forms derived from 8 different Trypanosoma cruzi strains were compared with their capacity to infect in vitro cultured LLC-MK2 cells. A sensitive and reproducible titration method for lectin binding sites (ELLA: Enzyme Linked Lectin Assay) was employed, in which reactivities were scored through optical densities in an ELISA reader. Tissue culture trypomastigotes from the strains Y, CL, SC4, SC24, SC25, SC28, SC32 and SC33 were investigated for expression of different cell surface carbohydrate residues using Concanavalin A (ConA), Peanut agglutinin (PNA), Soybean agglutinin (SBA) and Wheat germ agglutinin (WGA) conjugated to peroxidase. The reactivity of the strains to PNA lectin was SC28>SC32>SC33>SC25>SC24>Y>CL>SC4. The optical density values obtained were highly correlated (r2 = 0.986, p < 10−4) with the number of parasitized LLC-MK2 cells 24 hours after infection by trypomastigotes from each corresponding strain. We concluded that galactose and N-acetyl-D-galactosamine residues that are present on the surface of trypomastigotes are important in host-cell recognition.