Detection of oxidative DNA damage by a monoclonal antibody: role of lysyl residues in antigen binding
Detection of oxidative DNA damage by a monoclonal antibody: role of lysyl residues in antigen binding
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DOI：
10.1016/s0165-2478(98)00024-8
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发表时间：
1998-06-01
影响因子：
4.4
通讯作者：
Ali, R
中科院分区：
文献类型：
--
作者：
Ahmad, J;Ashok, BT;Ali, R
羟基自由基是活性氧的重要实体，已知可以修饰细胞 DNA，并与多种人类疾病有关。本研究中使用了先前描述的针对活性氧修饰 DNA (ROS-DNA) 的单克隆抗体 (Mab)，该抗体优先识别 DNA 上 ROS 修饰的表位。对 Mab 赖氨酸的 E-氨基进行修饰，以研究这些残基在 Mab 与 ROS-DNA 结合中的作用。结果表明，赖氨酰残基的修饰与 Mab 与 ROS-DNA 结合的损失平行，达到 73%，这表明这些带正电荷的氨基酸残基在 Mab 的互补决定区域中可能发挥作用，该 Mab 还用作免疫化学探针来检测 SLE 体内氧化性 DNA 损伤。 Mab 清楚地识别了来自 SLE 患者的 8 个 DNA 样本中的 5 个，并在抑制测定中给出了 57%、58%、63%、64% 和 70% 的最大抑制，同时不与作为阴性对照的正常健康人群的 DNA 发生反应。优先结合 ROS 修饰表位的 Mab 对 SLE 患者 DNA 分离物的高度识别表明这些患者的氧化应激增加，导致 DNA 损伤，这可能有助于诱导抗体与天然 DNA (nDNA) 发生交叉反应。 (C) 1998 Elsevier Science B.V. 保留所有权利。
Hydroxyl radical, a prominent entity of reactive oxygen species, is known to modify cellular DNA and has been implicated in several human diseases. A previously described monoclonal antibody (Mab) against reactive oxygen species-modified DNA (ROS-DNA), which preferentially recognizes ROS-modified epitopes on DNA, was used in this study. The E-amino groups of lysine of the Mab were modified to study the role of these residues in Mab binding to ROS-DNA. The results demonstrate that modification of lysyl residues paralleled loss in Mab binding to ROS-DNA to the extent of 73%, suggesting the probable role of these positively charged amino acid residues in the complementarily determining regions of the Mab, The Mab was also used as an immunochemical probe to detect oxidative DNA damage in vivo in SLE. The Mab distinctly recognized five DNA samples out of eight from SLE patients and gave maximum inhibitions of 57, 58, 63, 64 and 70% in inhibition assay, while not reacting with DNA from normal, healthy population which served as negative control. High recognition of DNA isolates from SLE patients by the Mab having preferential binding to ROS-modified epitopes indicates increased oxidative stress in these patients leading to DNA damage which may contribute to the induction of antibodies cross-reacting with native DNA (nDNA). (C) 1998 Elsevier Science B.V. All rights reserved.