FIGURE 2. DCs from malaria infected mice induced cytokine expression by OT-II T cells.

Spleen T cells from naïve OT-II transgenic mice were cocultured with spleen DCs from P. yoelii-infected WT, TLR2^−/−, TLR4^−/−, TLR9^−/− and MyD88^−/− mice at the indicated days postinfection in the presence of OVA^323–339 peptide. After 72 h, the culture supernatants were collected and assayed for TNF-α (A), IFN-γ (B), IL-12 (C), IL-10 (D) and IL-4 (E) by ELISA. Cocultures not treated with OVA peptide were used as controls. Data are a representative of three independent experiments, each performed in duplicates. Note: 5 d DC plus T, 10 d DC plus T, and 17 d DC plus T refers to cocultures of spleen DCs from mice at 5, 10, and 17 days postinfection and OT-II T cells from naïve mice. The letters, a and b, indicate the statistical significance between the levels of cytokines produced by OT-II T cells activated with DCs from the indicated gene knockout mice and those produced by OT-II T cells activated with DCs from the corresponding infected WT mice. a, p <0.001; b, p <0.01. (F) OT-II T cells and DCs from mice at 5 and 10 days postinfection were cocultured for 6–12 h in the presence of OVA peptide and then added GolgiPlug. Production of TNF-α and IFN-γ by T cells were analyzed by flow cytometry after intracellular staining with anti-cytokine antibodies. Histograms show the percent positive OT-II T cells for each cytokine. (G) Spleen DCs from mice at 5 days postinfection were cultured either alone or with OT-II T cells in presence of OVA peptide. After 24 or 48 h, DCs were surface stained with annexin V and analyzed by flow cytometry. Histograms indicate the percentage of annexin V positive cells in gated DCs in coculture vs. control DC culture.