Phase transitions in human IgG solutions.
Phase transitions in human IgG solutions.
复制标题
DOI：
10.1063/1.4811345
复制
发表时间：
2013-09
期刊：
影响因子：
--
通讯作者：
Ying Wang;A. Lomakin;R. F. Latypov;J. Laubach;T. Hideshima;P. Richardson;N. Munshi;K. Anderson;G. Benedek
中科院分区：
文献类型：
--
作者：
Ying Wang;A. Lomakin;R. F. Latypov;J. Laubach;T. Hideshima;P. Richardson;N. Munshi;K. Anderson;G. Benedek
在各种溶液条件下，已在浓缩抗体溶液中观察到蛋白质缩合，如结晶、液-液相分离、聚集和凝胶化。虽然大多数IgG抗体是相当可溶的，但少数异常值可以在生理条件下发生缩合。IgG的浓缩可在一些人类疾病和生物药物制剂中引起严重后果。在浓缩的IgG溶液中的蛋白质凝聚的相变也是理解非球形蛋白质分子的相行为的基本兴趣。由于通用IgG的高溶解度，IgG溶液的相行为尚未得到很好的研究。在这项工作中，我们提出了一种实验方法来研究IgG溶液中的相变是隐藏在冰点以下的解决方案。使用这种方法，我们已经研究了六个人骨髓瘤IgG和两个重组药物人IgG的液-液相分离。我们还研究了两种人冷球蛋白IgG的结晶与液-液相分离的关系。实验结果揭示了IgG溶液一般相行为的几个重要特征：（1）所有IgG溶液的共存曲线形状相似，但与准球形蛋白质的共存曲线形状有很大不同;（2）所有IgG溶液的临界点都位于大约相同的蛋白质浓度（~100 mg/ml），但它们的临界温度有很大差异;和（3）IgG溶液中的液-液相分离相对于结晶是亚稳的。IgG溶液的相行为的这些特征反映了所有IgG具有几乎相同的分子几何形状但相当不同的净蛋白质间相互作用能的事实。这项工作为进一步研究通用IgG的相行为以及具有大的凝聚倾向的离群值提供了实验和理论基础。研究IgG溶液的相图对于理解免疫球蛋白沉积疾病以及理解IgG药物制剂的胶体稳定性具有重要意义。
Protein condensations, such as crystallization, liquid-liquid phase separation, aggregation, and gelation, have been observed in concentrated antibody solutions under various solution conditions. While most IgG antibodies are quite soluble, a few outliers can undergo condensation under physiological conditions. Condensation of IgGs can cause serious consequences in some human diseases and in biopharmaceutical formulations. The phase transitions underlying protein condensations in concentrated IgG solutions is also of fundamental interest for the understanding of the phase behavior of non-spherical protein molecules. Due to the high solubility of generic IgGs, the phase behavior of IgG solutions has not yet been well studied. In this work, we present an experimental approach to study IgG solutions in which the phase transitions are hidden below the freezing point of the solution. Using this method, we have investigated liquid-liquid phase separation of six human myeloma IgGs and two recombinant pharmaceutical human IgGs. We have also studied the relation between crystallization and liquid-liquid phase separation of two human cryoglobulin IgGs. Our experimental results reveal several important features of the generic phase behavior of IgG solutions: (1) the shape of the coexistence curve is similar for all IgGs but quite different from that of quasi-spherical proteins; (2) all IgGs have critical points located at roughly the same protein concentration at ~100 mg/ml while their critical temperatures vary significantly; and (3) the liquid-liquid phase separation in IgG solutions is metastable with respect to crystallization. These features of phase behavior of IgG solutions reflect the fact that all IgGs have nearly identical molecular geometry but quite diverse net inter-protein interaction energies. This work provides a foundation for further experimental and theoretical studies of the phase behavior of generic IgGs as well as outliers with large propensity to condense. The investigation of the phase diagram of IgG solutions is of great importance for the understanding of immunoglobulin deposition diseases as well as for the understanding of the colloidal stability of IgG pharmaceutical formulations.