MR is essential for omega-1–driven Th2 polarization in vivo. MR^−/− and WT Bl/6 mice were injected s.c. with omega-1 (ω-1; 2 µg in 30 µl PBS) or PBS into the footpad. (A) After 7 d, the cells from the draining LNs were restimulated in vitro for 4 d with PBS, 2 µg/ml omega-1, or 10 µg/ml PHA, as polyclonal stimulus, after which cytokine production was determined by ELISA. (B) Intracellular cytokine production of the CD3⁺/CD4⁺ T cells from these LNs was assayed by FACS after an additional 6-h restimulation with PMA and ionomycin. FACS plots show concatenated data from four mice. The bar graphs represent the percentage of T cells single-positive for either IL-4 or IFN-γ. One of two independent experiments is shown. Data are means ± SEM of four mice per group based on pooled triplicate wells for each mouse. *, P < 0.05; **, P < 0.01 for significant differences based on paired analysis (two-sided paired Student’s t test).