Use of single point mutations in domain I of β2-glycoprotein I to determine fine antigenic specificity of antiphospholipid autoantibodies
Use of single point mutations in domain I of β2-glycoprotein I to determine fine antigenic specificity of antiphospholipid autoantibodies
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DOI：
10.4049/jimmunol.169.12.7097
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发表时间：
2002-12-15
影响因子：
4.4
通讯作者：
Linnik, MD
中科院分区：
文献类型：
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作者：
Iverson, GM;Reddel, S;Linnik, MD
针对 β(2)-糖蛋白 I (β(2)GPI) 的自身抗体似乎是抗磷脂综合征 (APS) 的一个关键特征。根据结构域缺失突变体的测定，人类自身抗体与 β(2)GPI 中存在的五个结构域中的第一个结合。在这项研究中，使用 10 个选定的完整 beta(2)GPI 突变体（在第一个结构域中含有单点突变）对结构域 I 表位的精细细节进行了检查。与 beta(2)GPI 的结合受到结构域 I 中许多单点突变的显着影响，特别是氨基酸 40-43 区域中的突变。分子模型预测这些突变会影响结构域 I 的表面形状和静电荷。突变 K19E 也有影响，尽管不那么严重并且涉及的患者也较少。两个不同的实验室在竞争性抑制 ELISA 中使用亲和纯化的抗 β(2)GPI 以及在直接结合 ELISA 中使用全血清获得了类似的结果。这项研究证实，抗 β(2)GPI 自身抗体与结构域 I 结合，并且由残基 40-43 定义的带电表面斑块有助于形成显性靶表位。
Autoantibodies against beta(2)-glycoprotein I (beta(2)GPI) appear to be a critical feature of the antiphospholipid syndrome (APS). As determined using domain deletion mutants, human autoantibodies bind to the first of five domains present in beta(2)GPI. In this study the fine detail of the domain I epitope has been examined using 10 selected mutants of whole beta(2)GPI containing single point mutations in the first domain. The binding to beta(2)GPI was significantly affected by a number of single point mutations in domain I, particularly by mutations in the region of aa 40-43. Molecular modeling predicted these mutations to affect the surface shape and electrostatic charge of a facet of domain I. Mutation K19E also had an effect, albeit one less severe and involving fewer patients. Similar results were obtained in two different laboratories using affinity-purified anti-beta(2)GPI in a competitive inhibition ELISA and with whole serum in a direct binding ELISA. This study confirms that anti-beta(2)GPI autoantibodies bind to domain I, and that the charged surface patch defined by residues 40-43 contributes to a dominant target epitope.