The Fab region of IgG impairs the internalization pathway of FcRn upon Fc engagement

Abstract

Disrupting the association between the Immunoglobulin G constant fragment (Fc) and the neonatal Fc receptor (FcRn) by engineered antibodies is a promising strategy to reduce autoantibody levels in autoimmune diseases. Here authors show that the variable fragment (Fab) of immunoglobulins could disturb the Fc-FcRn interaction, therefore the therapeutic effect of Fc-only fragments might surpass that of Fc-engineered antibodies with enhanced binding to FcRn.