Binding of 125I-Gamma Interferon to Cultured Human Keratinocytes

Gamma interferon (IFN-γ), a product of activated lymphocytes, influences keratinocyte proliferation and differentiation. Recombinant gamma interferon (r-IFN-γ) was radioiodinated using the Bolton-Hunter reagent and retained 90% of its biologic activity as determined by induction of HLA-DR expression. The biochemical ligand-binding properties of iodinated IFN-γ to cultured human keratinocytes revealed a plateau of binding at 150mm at 4°C, and a single class of specific high affinity receptors (kD = 1.3 × 10-10) M; 2200 sites/cell). The binding of human IFN-γ, to keratinocytes was inhibited by human r- IFN-γ, but not by either murine recombinant gamma interferon or human recombinant beta interferon (r-IFN-β). The presence of high affinity receptor sites on human keratinocytes assures the reception of appropriate immunologic signals in lymphocyte-keratinocyte interactions