Subiza J L, Caturla A, Pereira L F, Camargo M C, Bustos A, Boimorto R, de la Concha E G
Department of Immunology, Hospital Universitario San Carlos, Madrid, Spain.
J Autoimmun. 1992 Jun;5(3):363-77. doi: 10.1016/0896-8411(92)90149-k.
Murine monoclonal antibodies (mAb) reacting with affinity-purified antihistone antibodies (AHA) from serum of a patient with systemic lupus erythematosus (SLE) were obtained. One of them, 8B3, was initially considered to recognize idiotypic (Id) determinants in AHA since (a) it reacted with AHA but not with control IgG; (b) this reactivity could be inhibited using affinity-purified AHA, but not with control IgG or whole serum; (c) affinity-isolated 8B3+ antibodies showed antihistone activity and not other activities tested so far; (d) antihistone activity due to 8B3+, but not that of 8B3- from the same serum, could be fully inhibited by the presence of 8B3 mAb in the antihistone assay and (e) serum levels of 8B3 reactivity were higher than normal in SLE patients with AHA (56%), in contrast with SLE patients without AHA (6%). From these results it was deduced that 8B3 defined a cross-reactive Id shared by a subset of AHA in SLE patients. However, the present results suggest that (a) 8B3 mAb did not recognize AHA or Ig, but did recognize a 55 kDa histone-binding protein; (b) this 55 kDa protein was present free at low concentration in all human sera, but also associated with IgG in 8B3+ SLE sera and (c) these complexes are responsible for the false positive results in the antihistone assay as shown for DNA/anti-DNA complexes. Thus, mAbs recognizing the non-Ig moiety of circulating immune complexes may resemble anti-Id antibodies with features of the so-called epibodies. These immune complexes may be responsible for false positive results and caution should be exercised in the interpretation of results.
获得了与系统性红斑狼疮（SLE）患者血清中亲和纯化的抗组蛋白抗体（AHA）发生反应的鼠单克隆抗体（mAb）。其中之一8B3最初被认为识别AHA中的独特型（Id）决定簇，因为：（a）它与AHA反应但不与对照IgG反应；（b）这种反应性可用亲和纯化的AHA抑制，但不能用对照IgG或全血清抑制；（c）亲和分离的8B3 +抗体显示抗组蛋白活性，而不显示迄今测试的其他活性；（d）在抗组蛋白测定中，8B3 +的抗组蛋白活性，而非来自同一血清的8B3 -的抗组蛋白活性，可被8B3 mAb完全抑制；以及（e）与无AHA的SLE患者（6%）相比，有AHA的SLE患者中8B3反应性的血清水平高于正常水平（56%）。从这些结果推断，8B3定义了SLE患者中一部分AHA共有的交叉反应性Id。然而，目前的结果表明：（a）8B3 mAb不识别AHA或Ig，但识别一种55 kDa的组蛋白结合蛋白；（b）这种55 kDa的蛋白在所有人类血清中以低浓度游离存在，但在8B3 +的SLE血清中也与IgG相关联；以及（c）如DNA /抗DNA复合物所示，这些复合物是抗组蛋白测定中假阳性结果的原因。因此，识别循环免疫复合物非Ig部分的mAb可能类似于具有所谓表位特征的抗独特型抗体。这些免疫复合物可能是假阳性结果的原因，在结果解释中应谨慎。
