Nelson J L, Nardella F A, Oppliger I R, Mannik M
J Immunol. 1987 Mar 1;138(5):1391-6.
Considerable interest has focused on idiotypic cross-reactivity among antibody molecules. Cross-reactive idiotypes (Id) on monoclonal and polyclonal rheumatoid factors (RF) have been found frequently. Sufficient attention has not been directed, however, to the proportion of RF exhibiting the cross-reactivity, leaving the impression of extensive RF cross-reactivity when, in fact, this might represent a small minority of total RF molecules in a given individual. We have examined the polyclonal RF from patients with rheumatoid arthritis (RA) for cross-reactive Id in three different assays and with different Id-anti-Id systems. First, a sensitive liquid-phase radioimmunoassay was used in which panels of sera were tested for inhibition of different, idiotypically unrelated, Id-anti-Id interactions. When compared with normal sera, some of the sera from patients with RA caused minimal inhibition of Id-anti-Id interactions. None, however, caused marked inhibition of any Id-anti-Id system. Secondly, the panels of sera were also tested in a direct binding ELISA to detect partially cross-reactive Id that may not have been identified in the inhibition radioimmunoassay without differing results. Finally, results similar to the autologous Id-anti-Id inhibition assay were also found when the panels of RA sera were tested in two nonautologous Id-anti-Id systems, in which the anti-Id reacted with other than their own Id. These studies indicate that although cross-reactivity with some RF of an individual's total RF population may be seen frequently, an individual's repertoire of RF is itself private, quite diverse, and unique to that individual.
抗体分子间的独特型交叉反应性已引发了广泛关注。单克隆和多克隆类风湿因子（RF）上的交叉反应独特型（Id）已被频繁发现。然而，对于表现出交叉反应性的RF比例，尚未给予足够关注，这给人一种广泛的RF交叉反应性的印象，而实际上在特定个体中，这可能仅占总RF分子的一小部分。我们采用三种不同检测方法以及不同的Id-抗Id系统，对类风湿关节炎（RA）患者的多克隆RF进行交叉反应Id检测。首先，使用一种灵敏的液相放射免疫测定法，检测血清样本对不同的、独特型不相关的Id-抗Id相互作用的抑制作用。与正常血清相比，一些RA患者的血清对Id-抗Id相互作用的抑制作用极小。然而，没有一种血清能对任何Id-抗Id系统产生明显抑制。其次，血清样本还通过直接结合酶联免疫吸附测定法进行检测，以发现可能在抑制性放射免疫测定中未被识别的部分交叉反应Id，但结果并无差异。最后，当RA血清样本在两种非自身Id-抗Id系统中进行检测时，也得到了与自身Id-抗Id抑制测定相似的结果，在这两种系统中，抗Id与自身以外的Id发生反应。这些研究表明，虽然在个体的总RF群体中，某些RF的交叉反应性可能经常出现，但个体的RF库本身是私密的、相当多样的且独一无二的。
