Fig. 8. Normalization of epidermal differentiation of HaCaT organotypic co-cultures by cytokines. Epidermal tissue morphology of HaCaT organotypic co-cultures with postmitotic fibroblasts (3x10⁵) in collagen type-1 gel grown for 12 days in DMEM with 10% FCS (control) and treated with 2 ng/ml TGF-. Stimulated cultures were additionally supplemented with KGF (10 ng/ml), GM-CSF (100 ng/ml) or IL-1 (5 ng/ml). For comparison, organotypic co-cultures of normal epidermal keratinocytes (NEK) grown for 12 days on collagen gels with 3x10⁵/ml postmitotic fibroblasts are included (top row: H and E staining). By indirect immunofluorescence the late epidermal differentiation markers filaggrin (red), and loricrin (red) have been labelled. Nuclei were counterstained with bisbenzimide (blue). Bar, 100 µm.