Immunoglobulin G4: an odd antibody

Summary Despite its well‐known association with IgE‐mediated allergy, IgG4 antibodies still have several poorly understood characteristics. IgG4 is a very dynamic antibody: the antibody is involved in a continuous process of half‐molecules (i.e. a heavy and attached light‐chain) exchange. This process, also referred to as ‘Fab‐arm exchange’, results usually in asymmetric antibodies with two different antigen‐combining sites. While these...