Mammalian Interferon gamma is mainly produced by T lymphocytes and NK cells. It is a pleiotropic cytokine involved in the regulation of nearly all phases of immune and inflammatory responses，including the activation，growth and differentiation of T cell，B cells，macrophages，NK cells and other cell types such as endothelial cells and fibroblasts. It has weak antiviral and antiproliferative activity，and poteniates the antiviral and anti tumor effects of IFN alpha / beta (type I interferon). It is upregulated by IL2，FGF basic，EGF and downregulated by vitamin D3 or DMN. Labile at pH 2.