Kato T, Yamamoto K, Takeuchi H, Okubo M, Hara E, Nakada S, Oda K, Ito K, Nishioka K
Institute of Medical Science, St. Marianna University School of Medicine, Kanagawa, Japan.
Arthritis Rheum. 1993 Nov;36(11):1580-7. doi: 10.1002/art.1780361113.
To investigate the distribution of B cell autoepitopes of human DNA topoisomerase I (topo I), an autoantigen associated with scleroderma.
A complementary DNA clone, T1B, was used to produce recombinant proteins of topo I as beta-galactosidase fusion proteins. Immunoreactivity to these fusion proteins was then tested in 35 anti-topo I-positive sera from patients with scleroderma, by immunoblotting, enzyme-linked immunosorbent assay, and double immunodiffusion.
One epitope was found to be universally recognized by all sera tested. Thirty-two of the samples recognized multiple antigenic regions, but sera from the remaining 3 patients recognized only this universal epitope, and in longitudinal studies of 1 of these 3 patients, the serum recognized only this epitope for more than 2 years, even though multiple, potent, antigenic regions were found on topo I.
Recognition of multiple epitopes in most patients suggests that the topo I molecule itself would drive the autoimmunity on topo I. However, antigen-driven autoimmunity could not explain the production of the monoreactive anti-topo I antibody seen in the 3 patients. We thus hypothesize that there is a process whereby recognition of the universal epitope by cross-reaction develops into antigen-driven autoimmunity.
研究与硬皮病相关的自身抗原人DNA拓扑异构酶I（拓扑异构酶I）的B细胞自身表位分布情况。
使用互补DNA克隆T1B制备拓扑异构酶I的重组蛋白，作为β-半乳糖苷酶融合蛋白。然后通过免疫印迹、酶联免疫吸附测定和双向免疫扩散，检测35份硬皮病患者抗拓扑异构酶I阳性血清对这些融合蛋白的免疫反应性。
发现一个表位被所有检测血清普遍识别。32份样本识别多个抗原区域，但其余3名患者的血清仅识别这个普遍表位，并且在对这3名患者中的1名进行的纵向研究中，该血清在2年多的时间里仅识别这个表位，尽管在拓扑异构酶I上发现了多个强效抗原区域。
大多数患者对多个表位的识别表明拓扑异构酶I分子本身会引发针对拓扑异构酶I的自身免疫。然而，抗原驱动的自身免疫无法解释在这3名患者中出现的单反应性抗拓扑异构酶I抗体的产生。因此，我们假设存在一个过程，即通过交叉反应对普遍表位的识别发展为抗原驱动的自身免疫。
