Immunohistochemical demonstration of FC receptors in rat tissues using immune complexes as ligand

Summary To demonstrate the presence and localization of Fc receptors, rat liver cryostat sections were incubated with heterologous and autologous immune complexes (ICx) and immunoglobulin (Ig) aggregates. Binding was demonstrated using the immunoperoxidase technique. Autologous and heterologous ICx as well as aggregates from human and rat Ig appeared to bind to the sinusoidal wall. ICx bind in preference to aggregates. Monomeric Ig and aggregated Ig from swine and rabbit did not bind. The results demonstrated that ICx and rat and human Ig aggregates were bound via an Fc receptor. This Fc receptor was still intact in livers from carbontetra chloride and galactosamine treated rats. The receptor could also be demonstrated on spleen macrophages and on kidney interstitial cells. This method turned out to be an useful functional histochemical method to localize Fc receptors and to demonstrate their affinity and species specificity in tissues.