Figure 7.

Interleukin-21 (IL-21) depletion increases cytokine production by antigen-specific CD4 T cells. Mice were immunized and challenged as described in Figure 2 (“−”: Isotype control, “+” anti-IL-21). Five days post challenge, lungs were harvested. CD4 T cells were sorted by magnetic activation cell sorter and dendritic cells (DCs) sorted by fluorescent-activated cell sorter. DCs (4 × 10⁴ cells per well) were pulsed with specific (G184-198; p31) peptide or control (G64-78; p11) peptide (10 μg ml⁻¹) for 1 h before co-culture with CD4 T cells (4 × 10⁵ cells per well). Cells were incubated for 72 h, the supernatants were harvested, and (a) interferon (IFN)-γ, (b) IL-10, (c) IL-21, (d) IL-4, and (e) IL-17 levels were determined by sandwich enzyme-linked immunosorbent assay. The graphs are representative of three independent experiments of five mice per group. Student's t-test result; *P<0.05, ***P<0.001.