Singh Shubhadra N, Yadav Sandeep, Shire Steven J, Kalonia Devendra S
Process and Formulation Development, Olympus Biotech Corporation, Lebanon, New Hampshire, USA.
Pharm Res. 2014 Sep;31(9):2549-58. doi: 10.1007/s11095-014-1352-0. Epub 2014 Mar 18.
The purpose of this study was to investigate the contribution of the dipole moment to overall protein-protein interactions and viscosity of a monoclonal antibody MAb1.
The dipole moment of MAb1 was measured at various solution pH conditions using dielectric relaxation spectroscopy.
The dipole moment for MAb1 was highest at pH 6.5, and the pH dependent change in molecular dipole correlated fairly well with previously observed trends of viscosity and storage modulus versus pH. Moreover, the magnitude of the dielectric increment at pH 6.5 and 7.0 showed strong concentration dependence, indicating the presence of relatively strong dipole-dipole interactions at these pHs. To test if the cluster of charged residues present in the Fab contributes to the mean dipole moment observed for MAb1, additional mutants involving charge mutations in the CDR were investigated. In contrast to MAb1, all of the other MAbs showed significantly reduced pH and concentration dependence of the measured dipole moments and dielectric increments, respectively.
The solution pH dependent measured dipole moments of MAb1 appears to be in line with the observed intermolecular interactions and viscosity behavior suggesting that dipole-dipole interaction plays an important role in governing the high concentration solution behavior of this MAb.
本研究旨在探究偶极矩对单克隆抗体MAb1整体蛋白质-蛋白质相互作用及黏度的影响。
使用介电弛豫光谱法在不同溶液pH条件下测量MAb1的偶极矩。
MAb1的偶极矩在pH 6.5时最高，分子偶极随pH的变化与先前观察到的黏度和储能模量随pH变化的趋势相当吻合。此外，pH 6.5和7.0时的介电增量幅度呈现出强烈的浓度依赖性，表明在这些pH值下存在相对较强的偶极-偶极相互作用。为了测试Fab中存在的带电残基簇是否对MAb1观察到的平均偶极矩有贡献，研究了涉及CDR中电荷突变的其他突变体。与MAb1不同，所有其他单克隆抗体分别显示出测量的偶极矩和介电增量的pH和浓度依赖性显著降低。
MAb1溶液pH依赖性的测量偶极矩似乎与观察到的分子间相互作用和黏度行为一致，表明偶极-偶极相互作用在控制该单克隆抗体的高浓度溶液行为中起重要作用。
