A human monoclonal antibody against the cytokine interferon-gamma (IFN-gamma; IFNg), with potential immunomodulating activity. Upon administration, the anti-IFNg monoclonal antibody NI-0501 binds to and neutralizes IFNg. This inhibits IFNg-mediated signaling pathways and suppresses the activation of the immune system. IFNg, a cell-signaling protein, plays a key role in the regulation and activation of the immune system; its upregulation is associated with certain auto-immune and auto-inflammatory diseases in which the immune system is abnormally activated.