A Monoclonal Antibody to the NH 2 -Terminal Region of Human Interferon-γ Inhibits Its Antiproliferative Activity Without Affecting Its Internalization

Abstract

MAb IGMB-15, an anti-hIFN-γ MAb, neutralizes the antiproliferative activity of hIFN-γ without affecting that of hIFN-α or hIFN-β. The neutralizing capacity of MAb IGMB-15 is wide: it has been assessed on cell lines whose origin and sensitivity to hIFN-γ differ. The binding of hIFN-γ to its receptor and its subsequent internalization into the target cell were not influenced by the antibody. MAb IGMB-15 has been found to interact with hIFN-γ in solution but not when the lymphokine was associated with its cell surface receptor, showing that the growth of certain cell lines can be inhibited at the cell membrane level. This finding is consistent with the existence of an accessory factor responsible for the antiproliferative activity of hIFN-γ.