[Structure an functions of IgG subclasses]

Abstract

This review first deals with IgG subclasses according to the aspects that ascribe them their common class properties: general structure, enzymatic cleavage, synthesis, Gm allotypes. Then the subclass specific characteristics are described, comparing the main structural features (domains, hinge, disulfide bridges, kappa/lambda ratio). The IgG subclasses are further compared according to their effector functions, stressing those resulting from structural differences: classical pathway of complement activation, binding to Fc receptors, to protein A and to rheumatoid factors. Finally, a survey of the prolific works about antibody functions of IgG subclasses, allows a glimpse of the wide possible applications in this field.