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

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• 作者：Patrí ; cia R.A. Nagib ; Walderez O. Dutra ; Egler Chiari ; Conceiç ; ã ; o R.S. Machado
• 刊名：Experimental Parasitology
• 出版年：2007
• 出版时间：August 2007
• 年：2007
• 卷：116
• 期：4
• 页码：366-374
• 全文大小：655 K

文摘

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-γ 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-γ 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.