TY - JOUR
T1 - Variable region identical immunoglobulins differing in isotype express different paratopes
AU - Janda, Alena
AU - Eryilmaz, Ertan
AU - Nakouzi, Antonio
AU - Cowburn, David
AU - Casadevall, Arturo
PY - 2012/10/12
Y1 - 2012/10/12
N2 - The finding that the antibody (Ab) constant (C) region can influence fine specificity suggests that isotype switching contributes to the generation of Ab diversity and idiotype restriction. Despite the centrality of this observation for diverse immunological effects such as vaccine responses, isotype-restricted antibody responses, and the origin of primary and secondary responses, the molecular mechanism(s) responsible for this phenomenon are not understood. In this study, we have taken a novel approach to the problem by probing the paratope with 15N label peptide mimetics followed by NMR spectroscopy and fluorescence emission spectroscopy. Specifically, we have explored the hypothesis that the C region imposes conformational constraints on the variable (V) region to affect paratope structure in a V region identical IgG1, IgG2a, IgG2b, and IgG3 mAbs. The results reveal isotype-related differences in fluorescence emission spectroscopy and temperature-related differences in binding and cleavage of a peptide mimetic. We conclude that the C region can modify the V region structure to alter the Ab paratope, thus providing an explanation for how isotype can affect Ab specificity.
AB - The finding that the antibody (Ab) constant (C) region can influence fine specificity suggests that isotype switching contributes to the generation of Ab diversity and idiotype restriction. Despite the centrality of this observation for diverse immunological effects such as vaccine responses, isotype-restricted antibody responses, and the origin of primary and secondary responses, the molecular mechanism(s) responsible for this phenomenon are not understood. In this study, we have taken a novel approach to the problem by probing the paratope with 15N label peptide mimetics followed by NMR spectroscopy and fluorescence emission spectroscopy. Specifically, we have explored the hypothesis that the C region imposes conformational constraints on the variable (V) region to affect paratope structure in a V region identical IgG1, IgG2a, IgG2b, and IgG3 mAbs. The results reveal isotype-related differences in fluorescence emission spectroscopy and temperature-related differences in binding and cleavage of a peptide mimetic. We conclude that the C region can modify the V region structure to alter the Ab paratope, thus providing an explanation for how isotype can affect Ab specificity.
UR - http://www.scopus.com/inward/record.url?scp=84867426983&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84867426983&partnerID=8YFLogxK
U2 - 10.1074/jbc.M112.404483
DO - 10.1074/jbc.M112.404483
M3 - Article
C2 - 22930758
AN - SCOPUS:84867426983
SN - 0021-9258
VL - 287
SP - 35409
EP - 35417
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 42
ER -