Interferon γ (IFN-γ) is a homodimer produced by a variety of immune cells, mainly activated T cells and NK cells. In addition to its antiviral activity, IFN-γ is a potent activator of macrophages, has anti-proliferative effects on transformed cells, and can potentiate the antiviral and antitumor effects of type I interferons. IFN-γ shares 86% amino acid sequence identity with mouse IFN-γ.