Imunidade na doença de Chagas (Trypanosomiasis Americana)

Muniz, Julio

doi:10.1590/s0074-02761962000100006

Cited by 9 publications

(5 citation statements)

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“…The pathogenesis of these alterations is not understood, primarily because of the remarkable difficulty in finding parasites at the sites of the lesions (3, 4). The regular presence in the heart of mononuclear cell infiltrates composed of lymphocytes, monocytes, and plasma cells suggested the possible participation of immunological processes, especially autoimmune and delayed hypersensitivity reactions, in the pathogenesis of the chagasic cardiopathy (3,8). With regard to mechanisms of natural and acquired resistance to infection with T. cruzi, cellular immunity has been considered to play a role of major importance (4, 8, 9).…”

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confidence: 99%

Lymphocyte Transformation in Chagas Disease

1972

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The in vitro response of human peripheral lymphocytes to Trypanosoma (Schizotrypanum) cruzi antigens and to phytohemagglutinin was used to study the role of cellular immunity in Chagas disease (American trypanosomiasis). Solubilized T. cruzi antigens elicited 5 to 30% transformed cells in 5-day cultures of lymphocytes from adults chronically infected with T. cruzi. No major difference was noted between the response of 22 asymptomatic individuals and of 3 patients with chagasic cardiopathy. No correlation was found between degree of lymphocytic transformation and serum antibody titer. Lymphocytes from 15 normal controls yielded no significant transformation. Intradermal tests provoked a local delayed hypersensitivity reaction in infected individuals only, as evaluated clinically and histologically. The response to phytohemagglutinin of lymphocytes from chronically infected individuals was identical with that of normal controls.

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confidence: 99%

Lymphocyte Transformation in Chagas Disease

1972

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“…There is accumulating evidence that a steady balance between host and parasite is usually present in Chagas' disease and that cellular immunity is important in this balance: parasitemia is very low, and it is remarkably difficult to find parasites at the sites of the lesions (4); outbreaks of high parasitemia can be obtained only by using strong immunosuppressive agents (1,18); experimental, acute Chagas' disease is easily induced after neonatal thymectomy or treatment with antithymocyte serum (17,20); and immunity is achieved by lymphocyte transfer (7,16,18). On the other hand, the presence in the heart of mononuclear cell infiltrates suggests the possible participation of immune mechanisms, especially autoimmune and delayed hypersensitivity reactions, in the pathogenesis of the chagasic cardiopathy (14). In keeping with these concepts, Santos-Buch and Teixeira (19) have recently reported in vitro lysis of allogeneic, parasitized, and nonparasitized heart cells by T. cruzi-sensitized rabbit lymphocytes.…”

Section: Resultsmentioning

confidence: 88%

Cellular immunity in chronic Chagas' disease

Montufar¹,

Musatti²,

Silva³

et al. 1977

J Clin Microbiol

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The cellular immune response was assessed in 20 patients with chronic Chagas' disease (American trypanosomiasis). Thymus-derived lymphocyte function was determined in vivo by cutaneous reactivity to several antigens including a soluble preparation derived from Trypanosoma cruzi and sensitization to 2,4-dinitrochlorobenzene. The in vitro T-cell reactivity was investigated by the proliferative response to phytohemagglutinin and to T. cruzi antigen and by inhibition of leukocyte migration with the specific antigen. In addition, the proportion and absolute numbers of peripheral blood T and B-lymphocytes were determined by rosette formation. This research indicates that the general and specific cellular immune response, evaluated by the tests herein mentioned, is well preserved in patients, with Chagas' disease. We conclude that chronic Chagas' disease is not associated with deficiency in cellular immunity, nor does it lead to it. Conceivably, the active participation of delayed hypersensitivity may play an important role in the expression of the human chagasic lesions.

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“…The understanding of the immunological factors controlling the interaction of T. cruzi with its host is incomplete (5,11,15), including the question of the degree of participation of immune lysis and the possible role of complement in noncytotoxic reactions. The objective of the present study was to establish the main features of immune cytolysis of the crithidial stage, a developmental form readily obtainable in vitro which appears regularly in the insect vector, but not in the mammalian host.…”

Section: Discussionmentioning

confidence: 99%

“…The objective of the present study was to establish the main features of immune cytolysis of the crithidial stage, a developmental form readily obtainable in vitro which appears regularly in the insect vector, but not in the mammalian host. The latter may indeed be due to the prompt destruction of crithidial forms by immune cytolysis (15). Work is needed to establish the reaction mechanism of antibody and complement with the other developmental forms, some of which can be obtained in vitro (4), as well as the mechanism of resistance to immune lysis exhibited by certain forms of T. cruzi.…”

Section: Discussionmentioning

confidence: 99%

Role of Complement in Immune Lysis of Trypanosoma cruzi

et al. 1972

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Studies were performed on the mechanism of immune lysis of culture forms of Trypanosoma (Schizotrypanum) cruzi. Antibody-mediated lysis is caused by complement, which is activated via the classical pathway. The properdin system is not required. The kinetics of the reaction is similar to that followed by immune lysis of sensitized sheep erythrocytes, as is the concentration of divalent cations required for optimal lysis (0.15 mm Ca2+ and 0.5 mm Mg'+), the occurrence of cell membrane uptake of the complement components C3 and C4, and the development of characteristic ultrastructural modifications on the cell membrane.

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Imunidade na doença de Chagas (Trypanosomiasis Americana)

Cited by 9 publications

References 0 publications

Lymphocyte Transformation in Chagas Disease

Lymphocyte Transformation in Chagas Disease

Cellular immunity in chronic Chagas' disease

Role of Complement in Immune Lysis of Trypanosoma cruzi

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