Determination of Fab−Hinge Disulfide Connectivity in Structural Isoforms of a Recombinant Human Immunoglobulin G2 Antibody

摘要

The detection and characterization of unexpected disulfide-nmediated structural variants of human immunoglobulinnG2 (IgG2) antibodies was recently the subject of twoncopublications.1,2 In this paper, we present data to confirmnthe previously reported structures and elucidate thencomplete disulfide connectivity of each variant through thenapplication of a novel analytical methodology. In thisnmanner, the data illustrate the presence of at least fivenstructural variants, including the classical structure withnindependent Fab domains and a hinge region. Multiplensubvariants of the IgG2-A/B and IgG2-B structures arenidentified; these subvariants of each structure differnthrough the order of attachment of Fab peptides to thensequential hinge cysteines. Furthermore, the connectivitynof a novel subvariant of IgG2-B containing an intrachainndisulfide linkage in the lower hinge region is elucidated.nThe results presented in this paper reveal that the populationnof IgG2 disulfide structural variants is yet morencomplex than recently reported.