title: Trypanosoma cruzi: populations bearing opposite virulence induce differential expansion of circulating CD3+CD4-CD8- T cells and cytokine serum levels in young and adult rats.
abstract: The JG strain is the least virulent while the CL-Brener clone is one of the most virulent Trypanosoma cruzi populations in young rats. In this study, we determined that the parasitemia peak values in CL-Brener clone-infected adult rats were 50-fold lower than in young rats and that mortality was null as compared to 45% death in young rats. Low parasitemia, milder and sustained myocarditis and myositis characterized JG infections. CL-Brener clone caused a significantly higher production of pro-inflammatory cytokines and higher expansion of CD3(+)CD4(-)CD8(-), double-negative (DN) T cells, during the acute phase in both adult and young rats. DN T cell frequencies correlated with IFN-gamma levels. These findings may explain the higher inflammation and fast acute phase resolution in CL-Brener infection. In young rats, IL-10 levels were similar in both infections. The IL-10/IFN-gamma ratio was higher in JG acute infection in accordance with the milder inflammation and parasite persistence leading to a chronic phase. In conclusion, virulence and pathogenicity depend on T. cruzi ability to induce expansion of DN T cells and production of specific cytokines.
authors.affiliation: Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, MG, Brazil.
authors.forename: Patrícia R A
authors.initials: PR
authors.lastname: Nagib
authors.forename: Walderez O
authors.initials: WO
authors.lastname: Dutra
authors.forename: Egler
authors.initials: E
authors.lastname: Chiari
authors.forename: Conceição R S
authors.initials: CR
authors.lastname: Machado
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000097:blood; D014355:Chagas Disease / Q000276:immunology* / Q000469:parasitology; D016207:Cytokines / Q000097:blood*; D007371:Interferon-gamma / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013601:T-Lymphocytes / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000276:immunology* / Q000472:pathogenicity*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D014774:Virulence / Q000276:immunology
chemical_list: D017252:CD3 Complex; D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma