Department of Environmental and Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
Clin Chem. 2011 Jun;57(6):905-9. doi: 10.1373/clinchem.2010.157776. Epub 2011 Apr 11.
Analysis of circulating immune complexes (CICs) produced during an immune response may be useful in elucidating some aspects of this process. Identification of antigens incorporated into CICs provides information that may be helpful in developing diagnostic and treatment strategies for autoimmune diseases, infection, cancer, and transplantation therapy, and such information might be more relevant than information on free antigens. Because CICs may contain many antigens, comprehensive identification and profiling of such antigens is more effective than immunoblotting detection.
We developed a novel proteomic strategy (immune complexome analysis) in which immune complexes (ICs) are separated from serum, digested directly with trypsin, and then subjected to nano-liquid chromatography-tandem mass spectrometry for identifying and profiling antigens in CICs. We applied this strategy to the analysis of CICs in 21 rheumatoid arthritis (RA) patients. Serum samples from 13 healthy donors and 8 osteoarthritis patients were used as controls.
CICs containing thrombospondin-1 (TSP-1) and platelet factor 4 (PF4) were found in the serum of 81% and 52% of RA patients, respectively, and in none of the controls.
The ICs in the serum of a majority of the RA patients contained TSP-1 or PF4, and these ICs may have potential as alternative biomarkers. Our technique for immune complexome analysis uses routine clinical samples, simple protocols, and widely available equipment. This method may be generally applicable to the study of the relationship between CICs and certain diseases associated with the immune response in animals and humans.
分析免疫反应过程中产生的循环免疫复合物（CIC），可能有助于阐明该过程的某些方面。鉴定包含在 CIC 中的抗原可提供有助于开发自身免疫性疾病、感染、癌症和移植治疗的诊断和治疗策略的信息，此类信息可能比游离抗原的信息更相关。由于 CIC 可能包含许多抗原，因此全面鉴定和分析此类抗原比免疫印迹检测更有效。
我们开发了一种新的蛋白质组学策略（免疫复合物组学分析），其中将免疫复合物（IC）从血清中分离出来，直接用胰蛋白酶消化，然后进行纳流液相色谱-串联质谱分析，以鉴定和分析 CIC 中的抗原。我们将该策略应用于 21 例类风湿关节炎（RA）患者的 CIC 分析。将 13 名健康供体和 8 名骨关节炎患者的血清样本作为对照。
在 81%的 RA 患者和 52%的 RA 患者的血清中分别发现了含有血小板反应蛋白-1（TSP-1）和血小板因子 4（PF4）的 CIC，而在对照组中均未发现。
大多数 RA 患者的血清 IC 中含有 TSP-1 或 PF4，这些 IC 可能具有作为替代生物标志物的潜力。我们的免疫复合物组学分析技术使用常规临床样本、简单的方案和广泛可用的设备。该方法可能适用于研究 CIC 与动物和人类中与免疫反应相关的某些疾病之间的关系。
