Croissant M P, Zuzel M, Allain J P
Blood. 1983 Jul;62(1):133-40.
The interference of antibodies to factor VIII coagulant protein (VIII:C) of 9 nonhemophilic patients with the binding to factor VIII coagulant antigen (VIII:CAg) of a reference hemophilic 125I-Fab' reagent, used in a liquid phase VIII:CAg assay, was studied. The binding competition was estimated from immunoradiometric assay (IRMA) dose-response slope of VIII:CAg present in patient plasma, interference of antibodies with the 125I-Fab' binding to VIII:CAg in normal plasma, and the displacement of antibody from the complexes with VIII:CAg by the 125I Fab'. Antibody populations from three patients were studied in detail; in the VIII:CAg assay, two of them interfered with the 125I-Fab' binding, and one did not (patient 1). The formation of stable complexes between antibodies of each patient and VIII:CAg was demonstrated by protein-A-Sepharose adsorption. The 125I-Fab' binding to VIII:CAg-anti-VIII:CAg IgG complexes indicated that patient 1 antibodies and the 125I-Fab' recognized different antigenic determinants, whereas the other two patient antibodies and 125I-Fab' recognized closely related or identical VIII:CAg determinants. These results demonstrate an apparently selective recognition of at least two distinct VIII:CAg determinants by naturally occurring antibodies, suggesting a possibility of a wider use of these antibodies in studies of the structure and function of factor VIII.
研究了9名非血友病患者的抗体对凝血因子VIII（VIII:C）的干扰作用，这些抗体干扰了一种用于液相VIII:CAg检测的参考血友病125I-Fab’试剂与VIII:CAg的结合。通过患者血浆中VIII:CAg的免疫放射分析（IRMA）剂量反应斜率、抗体对正常血浆中125I-Fab’与VIII:CAg结合的干扰以及125I Fab’从VIII:CAg复合物中置换抗体，来估计结合竞争情况。对三名患者的抗体群体进行了详细研究；在VIII:CAg检测中，其中两名患者的抗体干扰了125I-Fab’的结合，一名患者的抗体未产生干扰（患者1）。通过蛋白A-琼脂糖吸附证明了每位患者的抗体与VIII:CAg之间形成了稳定的复合物。125I-Fab’与VIII:CAg-抗VIII:CAg IgG复合物的结合表明，患者1的抗体和125I-Fab’识别不同的抗原决定簇，而其他两名患者的抗体和125I-Fab’识别密切相关或相同的VIII:CAg决定簇。这些结果表明，天然抗体对至少两种不同的VIII:CAg决定簇具有明显的选择性识别，提示这些抗体在凝血因子VIII的结构和功能研究中可能有更广泛的应用。
