FcγRI is not usually expressed until induced by cytokines such as interferon‐γ on monocytes, neutrophils, macrophages, microglial cells in the brain, dendritic cells and mast cells. The sensitivity of FcγRI to interferon‐γ suggests that its in vivo activity is closely tied to immune activation events, and mouse studies have suggested that it has a critical role early in immune responses.19, 20 Its role in the MOA of antibodies may vary with anatomical location.21