Interferon-induced enhancement of macrophage Fc receptor expression: β-Interferon treatment of C3H/HeJ macrophages results in increased numbers and density of Fc receptors

Previous studies demonstrated that the augmentation of Fc receptor-(FcR) mediated phagocytosis and binding of opsonized sheep erythrocytes is cytokine mediated. Specifically, β-interferon- (β-IFN) and γ-IFN-rich preparations were shown to increase binding and phagocytosis of opsonized erythrocytes by C3H/HeJ macrophages. In this report we extend these studies by examination of the mechanisms by which highly purified β-IFN increases FcR capacity in C3H/HeJ macrophages. Our findings indicate that β-IFN augments FcR function for both IgG2a and IgG2b receptor subclasses. Moreover, this increased ability to bind and phagocytose opsonized erythrocytes is associated with a concomitant increase in both the number and surface membrane density of FcR.