Modulation of bullous pemphigoid antigens by gamma interferon in cultured human keratinocytes

We report the effects of human recombinant gamma interferon (gamma-IFN) on the expression of bullous pemphigoid (BP) antigens by human cultured keratinocytes. Secondary epidermal cell cultures were grown on 3T3 mouse fibroblasts; when confluent, some cultures were maintained in control medium while others were exposed to various concentrations of gamma-IFN (100, 200, 400 U/ml) for 14 days. The expression of BP antigens was analyzed by indirect immunofluorescence on epithelial sheets and immunoblotting of Tris, SDS, beta-mercaptoethanol culture extracts using different BP sera. Our results show that gamma-IFN alters the expression of BP antigens in a way varying according to the skin donor: we observed results ranging from complete loss and decreased expression to unchanged reactivity patterns. Thus, gamma-IFN modifies BP antigen expression; this behavior has been previously shown for other adhesion molecules such as fibronectin and thrombospondin. However, the observed variability of the expression of BP antigens according to the skin donor suggests an unexpected variability in keratinocyte sensitivity to gamma interferon, which remains to be explored both in vitro and in vivo.