Monoclonal Antibodies to the Human Interferon-γ Receptor: Blocking of the Biological Activities of Interferon-γ and Purification of the Receptor

Abstract

Monoclonal antibodies against the human interferon-γ (IFN-γ) receptor were developed by injecting mice with a preparation of receptor that was purified from solubilized placental membranes by ligand affinity chromatography. Three antibodies were identified by their ability to block the binding of ¹²⁵I-labeled IFN-γ to its receptor on HeLa cells at 4°C. One of these antibodies blocked several biological activities of IFN-γ, including its antiviral activity, its ability to induce HLA-DR surface antigens, and its ability to protect cells from NK cell-mediated cytotoxicity. This antibody exhibited higher binding capacity to cells at 37°C and was significantly less displaceable by an excess of IFN-γ as compared with the other two antibodies. Immunoaffinity chromatography of solubilized crude placental membrane preparation yielded a purified receptor that exhibited a molecular weight of 88,000. The purified receptor retained its ability to bind ¹²⁵I-labeled IFN-γ in solution.