THE STRUCTURAL REQUIREMENTS FOR COMPLEMENT ACTIVATION BY IGG - DOES IT HINGE ON THE HINGE

The flexibility of antibody molecules principally derives from the str ucture of the hinge region. It has generally been accepted that the fl exibility of the IgG hinge is necessary for complement activation to o ccur; however, recent studies dispute this premise. As described here by Ole Henrik Brekke, Terje Michaelsen and Inger Sandlie, it now appea rs that the only requirement of the hinge region for complement activa tion is the presence of inter-heavy-chain disulfide bonds(s). Furtherm ore, the structural basis for the differences between IgG subclasses w ith respect to effector functions appear to be located within the C(H) 2 domain of the immunoglobulin molecule.