title: Immunological response to re-infections with clones of the Colombian strain of Trypanosoma cruzi with different degrees of virulence: influence on pathological features during chronic infection in mice.
abstract: Re-infections with Trypanosoma cruzi are an aggravating factor for Chagas disease morbidity. The Colombian strain of T. cruzi represents multiclonal populations formed by clonally propagating organisms with different tropisms and degrees of virulence. In the present study, the influence of successive inoculations with clones of the Colombian strain, exhibiting different degrees of virulence, on chronic myocarditis and the humoral and cellular immune responses (Col-C1 high virulence, Col-C8 medium virulence and Col-C5 low virulence) were demonstrated. Mice from three groups with a single infection were evaluated during the acute (14th-30th day) and chronic phases for 175 days. An immunofluorescence assay, ELISA and delayed type hypersensitivity (DTH) cutaneous test were also performed. Mice with a triple infection were studied on the 115th-175th days following first inoculation. The levels of IgM and IgG2a were higher in the animals with a triple infection. DTH showed a higher intensity in the inflammatory infiltrate based on the morphometric analysis during a 48 h period of the triple infection and at 24 h with a single infection. The histopathology of the heart demonstrated significant exacerbation of cardiac inflammatory lesions confirmed by the morphometric test. The humoral responses indicate a reaction to the triple infection, even with clones of the same strain.
authors.affiliation: Laboratório de Chagas Experimental, Autoimunidade e Imunologia Celular, Centro de Pesquisas Gonçalo Moniz, Fiocruz, Salvador, BA, Brasil.
authors.forename: Marcos Lazaro da Silva
authors.initials: ML
authors.lastname: Guerreiro
authors.affiliation: Laboratório de Chagas Experimental, Autoimunidade e Imunologia Celular, Centro de Pesquisas Gonçalo Moniz, Fiocruz, Salvador, BA, Brasil.
authors.forename: Isa Rita Brito
authors.initials: IR
authors.lastname: Morais
authors.affiliation: Laboratório de Chagas Experimental, Autoimunidade e Imunologia Celular, Centro de Pesquisas Gonçalo Moniz, Fiocruz, Salvador, BA, Brasil.
authors.forename: Sonia Gumes
authors.initials: SG
authors.lastname: Andrade
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D014355:Chagas Disease / Q000469:parasitology* / Q000473:pathology; D002908:Chronic Disease; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D007111:Immunity, Cellular / Q000276:immunology; D051379:Mice; D009205:Myocarditis / Q000469:parasitology* / Q000473:pathology; D018512:Parasitemia / Q000276:immunology; D014349:Trypanosoma cruzi / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D014774:Virulence / Q000276:immunology
chemical_list: D000953:Antigens, Protozoan