Role of Fc Receptors as a Therapeutic Target

It has been forty years since the discovery of Fc Receptors and their function. Fc Receptors include the IgG receptors (FcγR), high-affinity IgE receptor (FcηRI), IgA and IgA/IgM receptors, and neonatal Fc receptor for IgG (FcRn). In particular, the FcγRs have been well known to play an important role in many biologic processes including those associated with the response to infection and cancer as well as in the pathogenesis of immune-mediated diseases. Both positive and negative regulatory function has ascribed to Fc receptors and FcγRs in particular which serve to establish a threshold for immune cell activation. In other cases, Fc receptors such as FcRn possess a novel structure and function by playing a major role in the transport of IgG across polarized epithelial barriers at mucosal surfaces and in the regulation of IgG halflife. These diverse functions highlight the potential effectiveness of targeting Fc receptors for therapeutic purposes. This review summarizes new information available in the therapeutic applications of this biology.