Phenotyping Polyclonal Kappa and Lambda Light Chain Molecular Mass Distributions in Patient Serum Using Mass Spectrometry
Phenotyping Polyclonal Kappa and Lambda Light Chain Molecular Mass Distributions in Patient Serum Using Mass Spectrometry
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DOI：
10.1021/pr5005967
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发表时间：
2014-11-01
影响因子：
4.4
通讯作者：
Murray, David L.
中科院分区：
文献类型：
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作者：
Barnidge, David R.;Dasari, Surendra;Murray, David L.
我们之前描述了一种 microLC-ESI-Q-TOF MS 方法，用于识别血清中的单克隆免疫球蛋白，然后使用其准确的分子质量跟踪它们随时间的变化。在这里，我们展示了如何使用相同的方法来识别和表征血清中的多克隆免疫球蛋白。我们结合基因序列数据的理论分子量和对来自正常人血清的市售纯化多克隆 IgG kappa 和 IgG lambda 的分析，确定通过 microLC-ESI-Q-TOF MS 观察到的两个分子量分布来自多克隆 kappa 和 lambda 轻链。通过微流 LC-ESI-Q-TOF MS 和免疫比浊法测定 74 个血清样本（25 个高丙种球蛋白血症、24 个低丙种球蛋白血症、25 个正常）的 kappa/lambda 比值的线性回归比较，斜率为 1.37，相关系数为 0.639。除了提供 kappa/lambda 比率之外，相同的 microLC-ESI-Q-TOF MS 分析还可以确定在患者样本中多克隆背景之上观察到的寡克隆轻链的分子量。在 2 名患有免疫疾病和高丙种球蛋白血症的患者中，我们观察到偏斜的多克隆分子质量分布，该分布转化为有偏差的 kappa/lambda 比率。质谱法提供了一种快速而简单的方法，将多克隆 kappa/lambda 轻链丰度比与优势单克隆和寡克隆轻链免疫球蛋白的鉴定相结合。我们预计这种评估免疫球蛋白轻链的方法将提高对免疫缺陷、自身免疫性疾病和抗体反应的理解。
We previously described a microLC-ESI-Q-TOF MS method for identifying monoclonal immunoglobulins in serum and then tracking them over time using their accurate molecular mass. Here we demonstrate how the same methodology can be used to identify and characterize polyclonal immunoglobulins in serum. We establish that two molecular mass distributions observed by microLC-ESI-Q-TOF MS are from polyclonal kappa and lambda light chains using a combination of theoretical molecular masses from gene sequence data and the analysis of commercially available purified polyclonal IgG kappa and IgG lambda from normal human serum. A linear regression comparison of kappa/lambda ratios for 74 serum samples (25 hypergammaglobulinemia, 24 hypogammaglobulinemia, 25 normal) determined by microflowLC-ESI-Q-TOF MS and immunonephelometry had a slope of 1.37 and a correlation coefficient of 0.639. In addition to providing kappa/lambda ratios, the same microLC-ESI-Q-TOF MS analysis can determine the molecular mass for oligoclonal light chains observed above the polyclonal background in patient samples. In 2 patients with immune disorders and hypergammaglobulinemia, we observed a skewed polyclonal molecular mass distribution which translated into biased kappa/lambda ratios. Mass spectrometry provides a rapid and simple way to combine the polyclonal kappa/lambda light chain abundance ratios with the identification of dominant monoclonal as well as oligoclonal light chain immunoglobulins. We anticipate that this approach to evaluating immunoglobulin light chains will lead to improved understanding of immune deficiencies, autoimmune diseases, and antibody responses.