Sugar-free antibodies--the bacterial solution to autoimmunity?

The enzyme EndoS from Streptococcus pyogenes is an immunomodulatory molecule hydrolyzing the conserved glycans in the effector part of immunoglobulin G (IgG). EndoS is remarkably specific for IgG, and hydrolysis has profound effects on IgG effector functions. EndoS pretreatment of IgG, or direct administration to animals with experimental antibody-mediated autoimmune diseases, inhibits development of disease or cures animals from established disease. The properties of EndoS make it a unique experimental tool and an attractive alternative to current therapies of conditions involving pathogenic antibodies. This review describes the discovery of EndoS, the effects of EndoS on IgG effector functions in vitro and in vivo, the biotechnological potential of EndoS, and the outcomes of EndoS treatment in animal models of autoimmunity.