A sole member makes up the type II IFNs that is called IFN-? (gamma). Mature IFN-? is an anti-parallel homodimer, which binds to the IFN-? receptor (IFNGR) complex to elicit a signal within its target cell. IFNGR is made up of two subunits each of molecules designated IFNGR1 and IFNGR2.
Sources and functions
IFN-? is involved in the regulation of the immune and inflammatory responses; in humans, there is only one type of interferon-gamma. It is produced in activated T-cells and natural killer cells. IFN-? has some anti-viral and anti-tumor effects, but these are generally weak. However, this cytokine potentiates the effects of the type I IFNs. IFN-? released by Th1 cells recruits leukocytes to a site of infection, resulting in increased inflammation. It also stimulates macrophages to kill bacteria that have been engulfed. IFN-? released by Th1 cells is also important in regulating the Th2 response. As IFN-? is vitally implicated in the regulation of immune response, its production can lead to autoimmune disorders.
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