An
Fc receptor is a protein found on the surface of certain cells – including, among others,
B lymphocytes,
follicular dendritic cells,
natural killer cells,
macrophages,
neutrophils,
eosinophils,
basophils, human
platelets, and
mast cells – that contribute to the protective functions of the
immune system. Its name is derived from its binding specificity for a part of an
antibody known as the
Fc (Fragment, crystallizable) region. Fc receptors bind to antibodies that are attached to infected cells or invading
pathogens. Their activity stimulates
phagocytic or
cytotoxic cells to destroy
microbes, or infected cells by
antibody-mediated phagocytosis or
antibody-dependent cell-mediated cytotoxicity. Some
viruses such as
flaviviruses use Fc receptors to help them infect cells, by a mechanism known as
antibody-dependent enhancement of infection.