Court W S, LoBuglio A F
Vox Sang. 1986;50(3):154-9. doi: 10.1111/j.1423-0410.1986.tb04869.x.
We have described the use of a monoclonal 125I-labeled anti-IgG (125I-MA) to assay IgG antibody displayed on the surface of platelets from normal and immune thrombocytopenic patients and reported levels of IgG 10-100-fold lower than previous studies. This report describes the immunologic characteristics of the 125I-MA and the assay for surface IgG. The 125I-MA has a high binding affinity for surface-displayed IgG (2.22 X 10(9) M-1), reacts equally well with all four subclasses of IgG and not at all with IgM or IgA. In our assay, the binding of 125I-MA was found to be greater than or equal to 99% specific for IgG (no nonspecific association of 125I-MA with platelets) and the binding ratio of 125I-MA to IgG displayed on the cell surface was 0.91 (close to unity). Finally, platelet lysates were found to contain large amounts of IgG protein (39,597 +/- 27,418 molecules/platelet) as compared to surface-displayed IgG (124 +/- 86 molecules/platelet). This assay has excellent characteristics for quantitation of IgG on platelets and the discrepancy with other techniques may, in part, be due to intentional or inadvertent lysis of platelets during assay conditions.
我们已经描述了使用单克隆125I标记的抗IgG（125I-MA）来检测正常人和免疫性血小板减少症患者血小板表面显示的IgG抗体，并报告其IgG水平比先前研究低10至100倍。本报告描述了125I-MA的免疫学特性以及表面IgG的检测方法。125I-MA对表面显示的IgG具有高结合亲和力（2.22×10⁹ M⁻¹），与IgG的所有四个亚类反应良好，而与IgM或IgA完全不反应。在我们的检测中，发现125I-MA的结合对IgG具有大于或等于99%的特异性（125I-MA与血小板无非特异性结合），并且125I-MA与细胞表面显示的IgG的结合率为0.91（接近1）。最后，与表面显示的IgG（124±86个分子/血小板）相比，发现血小板裂解物含有大量的IgG蛋白（39,597±27,418个分子/血小板）。该检测方法在定量血小板上的IgG方面具有优异的特性，与其他技术的差异可能部分归因于检测条件下血小板的有意或无意裂解。
