ATRA and Ro41 reciprocally regulate IL5 gene expression. In vitro differentiated 2xTh2 (open symbols) and 3xTh2 (closed symbols) cells were cultured with ATRA, Ro41, or DMSO vehicle for 6hrs. The expression of IL-5, IL-4, and IL-13 were determined by qRT-PCR and fold change (treated/vehicle) plotted. Th2 cell lines stimulated in the presence of IL-2 (50 U/ml) only. Data points represent individual Th2 cell lines. Paired Student’s t test was used to evaluate the data. Each symbol represents a specific cell line.