Soluble Fc Receptors

Abstract

In the early 1970s, soon after the discovery of Fc receptors on lymphocytes, molecules binding antigen-complexed IgG were detected in culture supernatants of mouse activated T cells and called IgG-binding factors (IgG-BF). These IgG-BF were hypothesized to be derived from membrane FcγR and to correspond to soluble forms of these receptors. Soluble forms of Fcγ receptors (sFcγR) were subsequently described in supernatants of cells of the immune system other than T cells and generalized to isotypes other than IgG. The cloning and identification of FcR genes allowed the molecular characterization of some of their soluble products and the demonstration that soluble FcR can be generated either by proteolytic cleavage of membrane FcR or by alternative splicing of TM-encoding exons of FcR genes.