Kasturi K N, Daian C, Saitoh Y, Muryoi T, Bona C A
Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029.
Mol Immunol. 1993 Aug;30(11):969-78. doi: 10.1016/0161-5890(93)90122-r.
In the previous studies we have shown that tight-skin (TSK) mouse is an experimental model for systemic sclerosis. This mutant mouse develops autoantibodies specific for scleroderma target antigens. To determine whether the expansion of autoantibody repertoire in TSK mouse occurs by selective expansion of certain variable region gene families, and whether CD5+ B cells contribute significantly to the production of autoantibodies, we have analyzed a panel of 60 hybridomas producing autoantibodies specific for scleroderma target autoantigens. Northern analysis of RNAs from these hybridomas showed that 70% were expressing genes from VHJ558 family while genes from 36-09 and J606 families were not at all represented. In contrast, in the cDNA libraries derived from splenic B cells, the expression of VHJ558 and 36-09 gene families were at an expected frequency corresponding to their genomic complexity (44% and 11.6%, respectively). These results demonstrate that there is a strong bias toward the use of J558 genes in TSK mouse autoantibody repertoire. On the other hand the expression of VK gene families was mostly random and corresponded to their frequency in splenic C kappa cDNA library. The pairing of VH:VK genes was stochastic. Analysis of the expression of J segments, however, revealed that JH2 and JK2 were predominantly used in the autoantibodies. Analysis of the expression CD5 mRNA in these hybridomas indicate that CD5+ B cells do not contribute significantly to the autoimmunity in TSK mice. These findings suggest that the expansion of peripheral autoreactive B cells in TSK mouse is determined by their immunoglobulin variable region rather than the genetic properties linked to a particular B cell subset.
在先前的研究中，我们已表明紧皮（TSK）小鼠是系统性硬化症的实验模型。这种突变小鼠会产生针对硬皮病靶抗原的自身抗体。为了确定TSK小鼠自身抗体库的扩增是否通过某些可变区基因家族的选择性扩增发生，以及CD5⁺ B细胞是否对自身抗体的产生有显著贡献，我们分析了一组60个产生针对硬皮病靶自身抗原的自身抗体的杂交瘤。对这些杂交瘤的RNA进行Northern分析表明，70%表达来自VHJ558家族的基因，而来自36 - 09和J606家族的基因完全未被代表。相反，在源自脾B细胞的cDNA文库中，VHJ558和36 - 09基因家族的表达频率与它们的基因组复杂性相对应（分别为44%和11.6%）。这些结果表明，在TSK小鼠自身抗体库中，对J558基因的使用存在强烈偏向。另一方面，VK基因家族的表达大多是随机的，且与它们在脾Cκ cDNA文库中的频率相对应。VH:VK基因的配对是随机的。然而，对J片段表达的分析表明，JH2和JK2在自身抗体中被主要使用。对这些杂交瘤中CD5 mRNA表达的分析表明，CD5⁺ B细胞对TSK小鼠的自身免疫没有显著贡献。这些发现表明，TSK小鼠外周自身反应性B细胞的扩增是由其免疫球蛋白可变区决定的，而不是与特定B细胞亚群相关的遗传特性。
