Figure 1.

Tumor necrosis factor-like cytokine 1A (TL1a) and interleukin-15 (IL-15) synergize to induce proinflammatory cytokine production in peripheral blood CD45RO⁺CD4⁺ T cells. Peripheral blood CD45RO⁺CD4⁺ T cells (1 × 10⁶ cells ml⁻¹, 200 μl per well) were cultured in medium alone (control) or with IL-12 (2 ng ml⁻¹), IL-18 (50 ng ml⁻¹), IL-15 (25 ng ml⁻¹), and TL1a (100 ng ml⁻¹) as indicated. (a) Representative intracellular staining (top) and percent (bottom row) of CD4⁺ T cells expressing interferon-γ (IFN-γ) 4 days after incubation with indicated cytokines or medium alone (control). Results are the mean (s.e.m.) of 10 biological replicates. Cells were pregated on live single cells. (b) Cytokine levels in culture supernatants were assessed after 1 day (IFN-γ) and 4 days (other cytokines). Results are the mean (s.e.m.) of 4 (IFN-γ), 6 (IL-22), or 13 (other cytokines) biological replicates.