FPS reduces production of cytokines by CD4+ cells. Mice were sensitized with OVA, infected with RSV then treated with FP, Sal or FPS as in Fig. 1A. They were sacrificed on day 15 and their splenocytes were examined for cytokine production by intracellular cytokine staining. Splenocytes were incubated on anti-CD3-coated plates (A) or with medium containing OVA (B) for 24 h and then treated with Golgi-Stop for 4 h to block cytokine secretion. Cells were surface-stained for CD4 and intracellularly for IFN-γ, IL10 or IL-4. The percent of CD4-gated cells producing the respective cytokine is shown. Results are from one representative experiment of two.