Effect of CD4+CD25+ T cell-depletion on acute lethal infection of mice with Trypanosoma congolense.

Despite the immense socio-economic repercussions of African trypanosomosis (AT), there is currently no effective control measure against the disease. Characterization of mechanisms governing resistance and/or susceptibility to AT could suggest interventions that might lead to more effective disease control. The present study was designed in an attempt to address the possible role of CD4+CD25+ T cells during an acute lethal infection of mice with Trypanosoma congolense, the causative agent of AT in domestic animals, through selective depletion using anti-CD25 monoclonal antibody. Accordingly, CD4+CD25+ T-cell-depletion resulted in a significant reduction or delay in parasitemia, pathology, and mortality, as compared to controls. The apparent resistance in CD4+CD25+-T-cell-depleted mice correlated with a profound suppression of Th2 cytokines in vitro and in vivo, culminating in a net Th1 cytokine environment. Cumulatively, these findings suggest that CD4+CD25+ T-cell- depletion improves the trypanotolerance of highly susceptible BALB/c mice acutely infected with the lethal T. congolense.