Cytokine secretion by Caco-2 cells in the presence of ragweed (RW) pollen. Caco-2 cells were cultured with different concentrations of chemically processed RW pollens for 24 h. Cytokines released from the cells were measured with ELISA. (A) IL-6, (B) IL-8, and (C) MCP-1 secretion stimulated by RW pollen. Values shown are means ± SD for three independent experiments. P ≤ 0.05 [*], P ≤0.01 [**], P ≤ 0.001 [***], P ≤ 0.0001 [****].