Fulcher C A, de Graaf Mahoney S, Zimmerman T S
Blood. 1987 May;69(5):1475-80.
We used immunoblotting of purified factor VIII coagulant protein (FVIII) to localize FVIII inhibitor epitopes in 76 inhibitor plasmas to either the 92-kd FVIII polypeptide (and its 54-kd and/or 44-kd thrombin fragments), the 80-kd polypeptide (and its 72-kd thrombin fragment), or both of these polypeptides. We also used immunoblotting to examine the immunoglobulin class and subclass content of 12 inhibitors with monoclonal antibodies specific for human IgG subclasses and IgM. Seven hemophilic (alloantibody) and five spontaneous (autoantibody) inhibitors contained IgG-1 and IgG-4 antibody; one of the spontaneous inhibitors also contained IgG-3. In one hemophilic inhibitor, the IgG-4 component reacted strongly with the 92-kd and 80-kd polypeptides, whereas the IgG-1 component reacted only minimally with the 92-kd polypeptide although its reactivity with the 80-kd polypeptide was strong. Another hemophilic inhibitor was affinity purified and subjected to quantitative radial immunodiffusion, and the presence of IgG-1 and IgG-4 antibody was confirmed. We conclude that the inhibitors examined are not monoclonal but are probably of restricted polyclonal origin and that different IgG subclasses in an inhibitor plasma can have different degrees of FVIII polypeptide reactivity.
我们采用纯化的凝血因子VIII（FVIII）蛋白进行免疫印迹，将76份含有FVIII抑制物的血浆中的FVIII抑制表位定位到92-kd FVIII多肽（及其54-kd和/或44-kd凝血酶片段）、80-kd多肽（及其72-kd凝血酶片段）或这两种多肽上。我们还使用免疫印迹法，用针对人IgG亚类和IgM的单克隆抗体检测了12份抑制物的免疫球蛋白类别和亚类含量。7份血友病（同种抗体）抑制物和5份自发性（自身抗体）抑制物含有IgG-1和IgG-4抗体；其中1份自发性抑制物还含有IgG-3。在1份血友病抑制物中，IgG-4成分与92-kd和80-kd多肽强烈反应，而IgG-1成分与92-kd多肽反应微弱，尽管其与80-kd多肽反应强烈。另一份血友病抑制物经亲和纯化后进行定量放射免疫扩散，证实存在IgG-1和IgG-4抗体。我们得出结论，所检测的抑制物不是单克隆的，可能起源于有限的多克隆，并且抑制物血浆中的不同IgG亚类对FVIII多肽的反应程度可能不同。
