文章：

在MUC16修订分子模型上定位CA125特异性抗体的结合位点

Mapping the Binding Sites of CA125-Specific Antibodies on a Revised Molecular Model of MUC16

原文发布日期：26 April 2025

DOI: 10.3390/cancers17091458

类型: Article

开放获取: 是

英文摘要：

Background: The ovarian cancer biomarker CA125 is a peptide epitope found in multiple tandem repeat domains of the mucin MUC16. Although efforts have been undertaken to characterize the interaction between CA125 and its clinically used antibodies, the molecular nature of the CA125 epitope(s) remains undefined. A recent revision of the molecular model of MUC16 provides an opportunity to fully characterize the binding between CA125-specific antibodies and the tandem repeat region of MUC16.Objectives: The objective of this study was to characterize the binding between CA125 antibodies and expressed tandem repeat proteins from MUC16 as part of a longer-term effort to identify the CA125 epitopes with amino-acid-level precision.Methods: Sixteen MUC16 tandem repeat proteins were expressed and purified. Protein expression was confirmed with high-resolution mass spectrometry. The binding interaction of each tandem repeat protein with four CA125-antibodies—the two used in the clinical test (OC125 and M11) and two clones defined as OC125-like and M11-like—was measured using indirect enzyme-linked immunosorbent assay (ELISA) and localized surface plasmon resonance (SPR).Results: Whereas M11 was found by ELISA to bind to all 16 tandem repeat proteins tested, OC125 does not bind to 5 of the 16 repeats. The recognition pattern of the antibodies was largely in agreement between ELISA and SPR, and cases in which binding is observed in ELISA but not in SPR can be attributed to insufficient contact time in SPR analysis.Conclusions: It can be inferred that the M11 epitope is present on all tandem repeats tested, whereas the OC125 epitope is present on fewer tandem repeats.

摘要翻译： 

背景：卵巢癌生物标志物CA125是黏蛋白MUC16多个串联重复结构域中的一种肽表位。尽管已有研究致力于表征CA125与其临床使用抗体之间的相互作用，但CA125表位的分子本质仍未明确。近期对MUC16分子模型的修订为全面表征CA125特异性抗体与MUC16串联重复区之间的结合提供了契机。 目的：本研究旨在表征CA125抗体与MUC16表达串联重复蛋白的结合特性，作为长期探索CA125表位氨基酸水平精确鉴定工作的一部分。 方法：表达并纯化16种MUC16串联重复蛋白，通过高分辨率质谱确认蛋白表达。采用间接酶联免疫吸附试验（ELISA）和局域表面等离子体共振（SPR）技术，测定每种串联重复蛋白与四种CA125抗体（临床检测使用的OC125和M11，以及被定义为OC125样和M11样的两种克隆抗体）的结合相互作用。 结果：ELISA检测发现M11能与所有16种测试的串联重复蛋白结合，而OC125不与其中5种重复序列结合。两种方法测得的抗体识别模式基本一致，ELISA检测到结合而SPR未检测到的情况可归因于SPR分析中接触时间不足。 结论：可推断M11表位存在于所有测试的串联重复序列中，而OC125表位仅存在于部分串联重复序列中。

原文链接：

Mapping the Binding Sites of CA125-Specific Antibodies on a Revised Molecular Model of MUC16