Oppliger I R, Nardella F A, Stone G C, Mannik M
J Exp Med. 1987 Sep 1;166(3):702-10. doi: 10.1084/jem.166.3.702.
The binding specificity of rheumatoid factors (RFs) to human Fc resembles that of some microbial Fc-binding proteins, suggesting conformational similarities in their Fc-binding regions. Using polyclonal chicken antibodies against SPA, we have detected a crossreactive determinant shared by human RFs from different individuals, but not by non-RF IgM and IgG. Chicken anti-SPA was shown to bind to 18 of 19 IgM RFs and 2 of 2 IgG RFs isolated from different individuals. This binding was inhibitable with SPA, fragment D of SPA, human IgG, and Fc fragment of IgG. The binding site for RF was located on the Fab' fragment of chicken anti-SPA. The antigenic mimicry of RFs by a protein of microbial origin suggests that the immune response to infectious agents could induce or modulate RF production through an internal image autoantiidiotype mechanism.
类风湿因子（RFs）与人Fc的结合特异性类似于某些微生物Fc结合蛋白，这表明它们的Fc结合区域在构象上具有相似性。利用针对葡萄球菌A蛋白（SPA）的多克隆鸡抗体，我们检测到不同个体的人RFs之间存在一个交叉反应性决定簇，但非RF IgM和IgG则没有。结果显示，鸡抗SPA能与从不同个体分离出的19种IgM RFs中的18种以及2种IgG RFs中的2种结合。这种结合可被SPA、SPA的D片段、人IgG和IgG的Fc片段抑制。RF的结合位点位于鸡抗SPA的Fab'片段上。微生物来源的一种蛋白质对RFs的抗原模拟表明，对感染因子的免疫反应可能通过内影像自身抗独特型机制诱导或调节RF的产生。
