Interferon gamma

Interferon gamma (IFNG or IFN-γ) is a <a href="/facts/Protein_dimer/c8LwFJPG">dimerized</a> soluble <a href="/facts/Cytokine/SdWpWABH">cytokine</a> that is the only member of the type II class of <a href="/facts/Interferon/63XfwpEh">interferons</a>. The existence of this interferon, which early in its history was known as immune interferon, was described by E. F. Wheelock as a product of human <a href="/facts/Leukocyte/vsDunUK0">leukocytes</a> stimulated with <a href="/facts/Phytohemagglutinin/Nl8AMfW4">phytohemagglutinin</a>, and by others as a product of antigen-stimulated <a href="/facts/Lymphocytes/pS2pv2Ma">lymphocytes</a>. It was also shown to be produced in human lymphocytes. or <a href="/facts/Tuberculin/Pcy2d05s">tuberculin</a>-sensitized mouse <a href="/facts/Peritoneal/BotJhUr0">peritoneal</a> lymphocytes challenged with <a href="/facts/Mantoux_test/bkmsTRYs">Mantoux test</a> (PPD); the resulting <a href="/facts/Supernatant/s3BgsLLY">supernatants</a> were shown to inhibit growth of <a href="/facts/Vesicular_stomatitis_virus/dud7fV3z">vesicular stomatitis virus</a>. Those reports also contained the basic observation underlying the now widely employed <a href="/facts/Interferon_gamma_release_assay/3x2PErun">interferon gamma release assay</a> used to test for <a href="/facts/Tuberculosis/ggPyovAl">tuberculosis</a>. In humans, the IFNG protein is encoded by the IFNG <a href="/facts/Gene/e1swwPY6">gene</a>.
Through cell signaling, interferon gamma plays a role in regulating the immune response of its target cell. A key signaling pathway that is activated by type II IFN is the <a href="/facts/JAK-STAT_signaling_pathway/t31RBT3X">JAK-STAT signaling pathway</a>. IFNG plays an important role in both <a href="/facts/Innate_immune_system/lz4BpSQI">innate</a> and <a href="/facts/Adaptive_immune_system/bc7zT1Jo">adaptive</a> immunity. Type II IFN is primarily secreted by CD4+ <a href="/facts/T_helper_cell/nhwAYkDj">T helper</a> 1 (Th1) cells, <a href="/facts/Natural_killer_cell/A3THWxrJ">natural killer</a> (NK) cells, and CD8+ <a href="/facts/Cytotoxic_T_cell/e5eRg3XJ">cytotoxic T cells</a>. The expression of type II IFN is upregulated and downregulated by cytokines. By activating signaling pathways in cells such as <a href="/facts/Macrophage/z7hkQu3o">macrophages</a>, <a href="/facts/B_cell/6Y1tgwwp">B cells</a>, and <a href="/facts/Cytotoxic_T_cell/e5eRg3XJ">CD8+ cytotoxic T cells</a>, it is able to promote inflammation, antiviral or antibacterial activity, and cell <a href="/facts/Cell_proliferation/Jp3hWo2t">proliferation</a> and <a href="/facts/Cellular_differentiation/bCVqUG7w">differentiation</a>. Type II IFN is serologically different from <a href="/facts/Interferon_type_1/jQhMAFA3">interferon type 1</a>, binds to different receptors, and is encoded by a separate chromosomal locus. Type II IFN has played a role in the development of <a href="/facts/Cancer_immunotherapy/0QKPeh5x">cancer immunotherapy</a> treatments due to its ability to prevent tumor growth.

Interferon gamma open-in-new

Interferon gamma