Figure 6. Involvement of E4bp4 in cytokine production by CD4⁺ IL-17RB⁺ iNKT cells in response to IL-25.

(A, B) Quantitative analysis of Rorc (A) and E4bp4 (B) in iNKT cell subtypes after cytokine treatment. Sorted iNKT cell subtypes (5×10⁴/100 µL) from thymus (left) or spleen (right) were co-cultured with BM-DCs (5×10³/100 µL) in the presence or absence of IL-23 (10 ng/ml) or IL-25 (10 ng/ml) for 24 h. The iNKT cell subtypes were then sorted again and analyzed for expression of the indicated genes by quantitative real-time PCR. The data are representative of three independent experiments (mean ± SEM). (C, D) Cytokine production by CD4⁺ IL-17RB⁺ iNKT cells in response to IL-25. Sorted CD4⁺ IL-17RB⁺ iNKT cells (5×10⁴/100 µL) from thymus (C) or spleen (D) of B6 or E4bp4 ^−/− mice were co-cultured with BM-DCs (5×10³/100 µL) in the presence of IL-25 (10 ng/ml) for 48 h and then the levels of the indicated cytokines in the tissue culture media were analyzed. iNKT cells from B6 were compared to those from E4bp4 ^−/− mice. ** p<0.01 calculated by t test. The data are representative of three independent experiments (mean ± SD).