Fig. 2

IL-4 impairs TNF-α-induced cell-surface expression of DC maturation markers. Dendritic cells were derived from human monocytes cultured for 5 days with GM-CSF (1000 IU/mL) and IL-4 (25 ng/mL). Maturation was induced after an additional 48-h culture with GM-CSF and 20 ng/mL TNF-α, in the absence (IL-4⁻) or presence (IL-4⁺) of 25 ng/mL IL-4. a Cells were stained with specific mAbs directed against CD83, CD86, HLA-DR or CD25 (bold lines) or their respective isotype controls (thin lines) and analyzed by flow cytometry. The figure in each histogram indicates the percentage of positive cells. The results are representative of 10 independent experiments. b Mean fluorescence intensity (MFI) for CD83, CD86, HLA-DR and CD25 expressed as the ratio of fluorescence intensity of specific labeling to background staining. The results are the mean ± SEM of MFI of ten separate experiments. *P < 0.05, compared to IL-4⁻-DC. c Cells were double-stained with FITC-anti-CD83 and APC-anti-CD25 antibodies and analyzed by flow cytometry. d The results are expressed as the mean ± SEM  % of IL-4⁻ and IL-4⁺-DC expressing the indicated markers in five separate experiments. *P < 0.05, compared to IL-4⁻-DC. e IL-4⁻ and IL-4⁺-DC were stimulated during an additional 24-h culture with 250 ng/mL recombinant soluble CD40L and underwent ELISA for IL-12p70 and IL-10 release. The results are the mean ± SEM of six to eight independent experiments. *P < 0.05, compared to IL-4⁻-DC