Figure 4.

Effects of MIF on melanogenesis in reconstituted three-dimensional human epidermis (MelanoDerm) cultures. A: The cultures (MelanoDerm) were treated with various concentrations of MIF for 9 days, with or without UV-B irradiation on days 1, 3, and 5. Equivalent numbers of cells were lysed with 1 N NaOH and measured for absorbance at 405 nm. The melanin content was estimated using a standard curve of synthetic melanin. The values are the mean ± SD derived from five equivalents (*P < 0.01). B: The cultures (MelanoDerm) were treated with neutralizing anti-MIF IgG antibody (10 or 30 μg/ml) or mouse IgG for 11 days with 100 mJ/cm² UV-B exposure, and the melanin content was estimated. The results are expressed as the mean ± SD of five experiments (*P < 0.0005, **P < 0.001, and ***P < 0.005). C: The cultures (MelanoDerm) were treated with 300 ng/ml MIF in combination with various concentrations of STI (a PAR-2 antagonist) or a c-kit/SCF-receptor antibody for 9 days, and the melanin content was estimated. The results are expressed as the mean ± SD of five experiments (*P < 0.001 and **P < 0.01). The data shown are representative of three independent experiments.