Human IFN gamma Recombinant Protein, eBioscience?. IFN gamma (Interferon gamma, Type II interferon) is a macrophage activation factor, and immune interferon that is produced primarily by T-lymphocytes and natural killer cells in response to antigens, mitogens, Staphylococcus enterotoxin B, phytohemaglutanin and other cytokines. IFN gamma is a dimeric protein consisting of two 146 amino acid subunits. IFN gamma is a glycoprotein that exists, functionally, as a homodimer of approximately 45 kDa. On SDS-PAGE, IFN gamma appears as a combination of 25, 20 and minor 15.5 kDa bands as a result of differential glycosylation. The biological activity of the IFN gamma homodimer is highly species specific. Human IFN gamma does not show cross-reac