The anti-beta2-glycoprotein I activity in human anti-phospholipid syndrome sera is due to monoreactive low-affinity autoantibodies directed to epitopes located on native beta2-glycoprotein I and preserved during species' evolution.
The anti-beta2-glycoprotein I activity in human anti-phospholipid syndrome sera is due to monoreactive low-affinity autoantibodies directed to epitopes located on native beta2-glycoprotein I and preserved during species' evolution.
复制标题
人抗磷脂综合征血清中的抗β2-糖蛋白I活性是由于针对位于天然β2-糖蛋白I上并在物种进化过程中保留的表位的单反应性低亲和力自身抗体所致。
作者：
A. Tincani;L. Spatola;E. Prati;F. Allegri;P. Ferremi;R. Cattaneo;P. Meroni;G. Balestrieri
为了研究抗磷脂综合征患者抗β2-糖蛋白I抗体(抗β2GPI)的反应模式，我们用5种不同抗磷脂综合征患者血清中的免疫球蛋白组份，用亲和层析的方法纯化了抗β2GPI抗体。亲和纯化的抗Beta2GPI代表了在人血清中发现的抗体，因为在固定化的人Beta2GPI柱上重复吸附后，它们的活性几乎可以从免疫球蛋白制剂中消除。我们的结果表明，亲和纯化的抗Beta2GPI：1)在没有任何磷脂的情况下与Beta2GPI反应，所用试剂中没有磷污染，以及它们在广泛的脱脂过程前后的结合活性相似；2)可以识别来自不同动物物种的Beta2GPI；3)能够与可溶性Beta2GPI结合，平均Kd值为4.65×10(-6)M(范围3，4-7，2×10(-6)M)；4)当Beta2GPI连接到固体载体上时，它们的结合亲和力显著增强；(5)以单反应性自身抗体为主。综上所述，我们发现人类多克隆抗Beta2GPI是低亲和力的，主要针对位于天然Beta2GPI上的一个表位的单反应自身抗体，并在物种进化过程中保存下来。
To characterize the reactivity pattern of Abs directed to beta2-glycoprotein I (anti-beta2GPI) in patients with anti-phospholipid syndrome, we have purified anti-beta2GPI Abs by affinity chromatography using the IgG fractions from sera of five different anti-phospholipid syndrome patients. Affinity-purified anti-beta2GPI were shown to be representative of Abs found in human sera because their activity could be virtually abolished from the IgG preparations after repeated absorptions on immobilized human beta2GPI column. Our results show that affinity-purified anti-beta2GPI: 1) do react with beta2GPI in the absence of any phospholipid, as demonstrated by the lack of phosphorus contaminant in the employed reagents, as well as by their comparable binding activity before and after extensive delipidation procedure; 2) can recognize beta2GPI regardless of its origin from different animal species; 3) are able to bind soluble beta2GPI with a mean Kd value of 4.65 x 10(-6) M (range 3, 4-7, 2 x 10(-6) M); 4) significantly enhance their binding avidity when beta2GPI is linked to a solid support; and 5) appear to be mainly monoreactive autoantibodies. In conclusion, we have shown that human polyclonal anti-beta2GPI are low affinity, mainly monoreactive autoantibodies directed to an epitope located on native beta2GPI, preserved along the species evolution.