Type I and Type II interferon receptors.

Binding site competition studies of 125I-interferon (IFN)-gamma were performed with homogeneous preparations of IFNs alpha 2, beta, and gamma. It was found that only IFN-gamma could compete for the specific binding site of 125I-IFN-gamma in both WISH and FS11 cells. Thus, a clear distinction between the receptor of IFN- alpha and beta on one hand, and the receptor of IFN-gamma on the other hand, was obtained. This result is unambiguous because all IFN preparations which were used were purified to homogeneity by specific monoclonal antibody immunoaffinity chromatography. We propose to assign the names "Type I" for the receptor of IFN-alpha and IFN-beta, and "Type II" for the specific receptor of IFN-gamma.