Binding of 125I-gamma interferon to cultured human keratinocytes

Gamma interferon (IFN-gamma), a product of activated lymphocytes, influences keratinocyte proliferation and differentiation. Recombinant gamma interferon (r-IFN-gamma) 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-gamma to cultured human keratinocytes revealed a plateau of binding at 150 min at 4 degrees C, and a single class of specific high affinity receptors (kD = 1.3 X 10(-10) M; 2200 sites/cell). The binding of human IFN-gamma, to keratinocytes was inhibited by human r-IFN-gamma, but not by either murine recombinant gamma interferon or human recombinant beta interferon (r-IFN-beta). The presence of high affinity receptor sites on human keratinocytes assures the reception of appropriate immunologic signals in lymphocyte-keratinocyte interactions.