Purification and properties of the alpha-interferon receptor of human lymphoblastoid (Namalva) cells.

The interferon receptor was solubilized from human lymphoblastoid (Namalva) cell membranes with Triton X-100. It was purified by chromatography on wheat-germ lectin-Sepharose and hydroxyapatite and by affinity chromatography on interferon-hexanoyl-Sepharose. The partially purified receptor was analyzed by gel filtration on Sepharose 6B and by sucrose gradient sedimentation in the presence of 0.1% Triton X-100. Gel filtration analysis yielded a Stokes radius of 74 A for the receptor-Triton X-100 complex. Sedimentation in sucrose gradients revealed an heterogeneous pattern of distribution with a plateau of activity between 4 and 10 S. Removal of suspected lipid material and Triton X-100 by extraction with isoamyl alcohol resulted in an accelerated rate of receptor sedimentation in a sodium dodecyl sulfate-containing sucrose gradient. Under these conditions it manifested an apparent sedimentation coefficient of 13.6 S. The dissociation constants Kd derived from Scatchard analysis of binding data with the purified receptor were in the range of 0.2-0.5 nM.