Surface glycoproteins of cultured human keratinocytes from normal and uninvolved psoriatic epidermis

Surface glycoproteins of cultured human keratinocytes from normal skin and uninvolved psoriatic epidermis, isolated by the suction blister method, were studied by two different methods. Cells were cultured on collagen-coated culture dishes and showed a fibrillar keratin-specific staining by immunofluorescence. Surface labelling experiments using the neuraminidase/galactose oxidase/sodium borohydride method (which labels the penultimate galactose moieties of glycoproteins) revealed one major glycoprotein with M_r 53 kD (kilodaltons) both in normal keratinocytes and in keratinocytes from uninvolved psoriatic skin. The periodate/sodium borohydride method (which labels the terminal sialic acids in glycoproteins) by contrast revealed three major glycoproteins, with M_r 53 kD to 63 kD, in normal keratinocytes but only a single major glycoprotein, with M_r 53 kD, in keratinocytes from uninvolved psoriatic skin. Treatment of cultured keratinocytes with etretinate appeared to restore the normal pattern of surface glycoproteins in uninvolved psoriatic keratinocytes.