FIG 4.

CpG treatment of chronically infected BALB/c mice results in decreased cytokine responses and the increased function of T regulatory cells. The immune response was evaluated 2 days following the last injection of CpG 1826 treatment (4 × 50 μg/dose) of established L. (V.) panamensis-infected BALB/c mice. Cytokine (IFN-γ, IL-10, IL-13, IL-17, TNF-α, and TGF-β) production was measured by ELISA in response to pLAg in draining lymph node cells from control (PBS)-treated and CpG 1826-treated mice (A). Chemokine and cytokine levels were measured using Luminex as described in Materials and Methods in response to pLAg in draining lymph node cells from control (PBS)- and CpG-treated mice (B). FACS analyses of Foxp3⁺ cells gated on CD4⁺ cells from the draining lymph nodes of infected mice (control and CpG treated) (C). FACS analyses of CD4⁺ Foxp3⁺ T cells expressing IFN-γ in draining lymph node cells from control- or CpG-treated infected mice (D). Levels of Foxp3 expression were comparable between CD4⁺ CD25⁺ cells isolated from naive and infected mice. The ability of CD4⁺ CD25⁺ cells from the draining lymph nodes of control- or CpG-treated infected mice to suppress proliferation of CD4⁺ CD25⁻ cells from naive mice in response to anti-CD3 and irradiated APC stimulation was assessed (E). Results represent data from two independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001.