Interferon-gamma (IFN-γ) signaling axis (IFN-γ axis)

The Natural killer (NK) cell IFN-γ signaling axis is a central immunological pathway where NK cells act as the primary innate source of Interferon-gamma (IFN-γ), a critical type II interferon (NIH, Wikipedia). Upon activation by cytokines such as IL-12 and IL-18 or through the engagement of activating receptors like CD16, NK cells rapidly produce and secrete IFN-γ (Frontiers in Immunology). This cytokine binds to the heterodimeric Interferon-gamma receptor (IFNGR1 and IFNGR2) on target cells, triggering the JAK-STAT signaling cascade involving JAK1, JAK2, and STAT1 (Bio-Rad, Wikipedia). The resulting transcription of interferon-stimulated genes (ISGs) enhances antigen presentation, promotes Th1 differentiation, and exerts anti-tumor effects (PubMed). Dysregulation of this axis is a key driver of Hemophagocytic lymphohistiocytosis (HLH) and is targeted by drugs like emapalumab, which neutralizes IFN-γ (FDA, NIH). Conversely, recombinant IFN-γ is used to treat chronic granulomatous disease, and JAK inhibitors are employed to dampen excessive signaling in various inflammatory conditions (StatPearls). The axis is also a focus in cancer immunotherapy, where enhancing NK cell IFN-γ production is sought to improve tumor clearance (Journal of Clinical Investigation). Safety concerns associated with modulating this axis include an increased risk of serious infections, particularly from mycobacteria and viruses, due to the essential role of IFN-γ in host defense (NIH).

Other names

Natural killer cell IFN-γ signaling axisInterferon-gamma signaling pathwayType II interferon signaling axisIFNG-IFNGR axisNK cell-IFN-gamma axisIFN-gamma/JAK/STAT1 pathway

Neutralization of circulating IFN-gamma, activation of the IFN-gamma receptor complex, or inhibition of downstream Janus kinase (JAK1/JAK2) signaling.