Fig. 1

Histological features and indirect immunoflorescence analysis of cultured human keratinocytes (left) and normal human epidermis (right) using an RA serum and MAbs AHF1 and AHF7 directed toward (pro)filaggrin and filaggrin, respectively

Cultured epithelial sheets (A) show a stratified architecture similar to that of normal epidermis (B). In the cultured epithelial sheets, the RA serum and the AHF MAbs produce labeling that is diffuse and of varying intensity in the stratum corneum and always intense and granular in the stratum granulosum where it labels the keratohyalin granules. In normal epidermis, the RA serum produces laminated labeling restricted to the stratum corneum, AHF1 stains the keratohyalin granules of the stratum granulosum and weakly recognizes the lower cornified layers of the stratum corneum, and the filaggrin-specific MAb AHF7 only stains the stratum corneum. Dotted lines denote the dermo-epidermal junction or the basal limit of the cultured epithelial sheets. SC, stratum corneum; SG, stratum granulosum; KHG, keratohyalin granules. Bars = 50 µm except in B = 100 µm.