ABSTRACT
Acute infection with Trypanosoma cruzi results in intense myocarditis, which progresses to a chronic, asymptomatic indeterminate form. The evolution toward this chronic cardiac form occurs in approximately 30% of all cases of T. cruzi infection. Suppression of delayed type hypersensitivity (DTH) has been proposed as a potential explanation of the indeterminate form. We investigated the effect of cyclophosphamide (CYCL) treatment on the regulatory mechanism of DTH and the participation of heart interstitial dendritic cells (IDCs) in this process using BALB/c mice chronically infected with T. cruzi. One group was treated with CYCL (20 mg/kg body weight) for one month. A DTH skin test was performed by intradermal injection of T. cruzi antigen (3 mg/mL) in the hind-footpad and measured the skin thickness after 24 h, 48 h and 72 h. The skin test revealed increased thickness in antigen-injected footpads, which was more evident in the mice treated with CYCL than in those mice that did not receive treatment. The thickened regions were characterised by perivascular infiltrates and areas of necrosis. Intense lesions of the myocardium were present in three/16 cases and included large areas of necrosis. Morphometric evaluation of lymphocytes showed a predominance of TCD8 cells. Heart IDCs were immunolabelled with specific antibodies (CD11b and CD11c) and T. cruzi antigens were detected using a specific anti-T. cruzi antibody. Identification of T. cruzi antigens, sequestered in these cells using specific anti-T. cruzi antibodies was done, showing a significant increase in the number of these cells in treated mice. These results indicate that IDCs participate in the regulatory mechanisms of DTH response to T. cruzi infection.
Subject(s)
Animals , Chagas Cardiomyopathy/drug therapy , Cyclophosphamide/pharmacology , Dendritic Cells/immunology , Hypersensitivity, Delayed/drug therapy , Immunosuppressive Agents/pharmacology , Trypanosoma cruzi , Antigen Presentation/immunology , Antigens, Protozoan/immunology , Chronic Disease , Chagas Cardiomyopathy/immunology , Hypersensitivity, Delayed/immunology , Mice, Inbred BALB C , Parasitemia/drug therapy , Parasitemia/immunology , Skin TestsABSTRACT
Vários estudos têm sugerido a possibilidade de transmissão de endoparasitos ao homem através de ingestão de frutas, verduras e hortaliças consumidas cruas, provenientes de áreas cultivadas e contaminadas por dejetos fecais. Com o objetivo de verificar a frequência de formas parasitárias em hortaliças, foram analisadas 30 amostras de alface crespa (Lactuca sativa) e 30 de agrião (Nasturdium officinale) provenientes de supermercados e feiras livres no município de Salvador (Bahia). As amostras foram pesadas e divididas em partes iguais, sendo uma parte lavada em água destilada e a outra em solução de hipoclorito de sódio. O conteúdo da lavagem foi deixado sedimentar por 24h e, em seguida, analisado. Das amostras examinadas, 95% estavam contaminadas, sendo 100% provenientes de feiras livres e 90% de supermercados. Os parasitos encontrados foram: cistos de Entamoeba sp, Endolimax sp, Giardia sp, oocistos não esporulados, ovos de ancilostomídeos, larvas de nematódeos, ovos de Ascaris, ácaros e Trichuris sp. Com os resultados obtidos evidencia-se a importância das hortaliças na transmissão de enteroparasitos bem como uma boa higienização das mesmas para o consumo in natura. Concluímos que essas duas variedades de hortaliças comercializadas nos dois estabelecimentos apresentaram índices de contaminação consideráveis, indicando que os procedimentos de cultivo e manuseio devem ser revistos.