Studies on immunoglobulin class switch recombination

我们鉴定了经细菌脂多糖(LPS)和转化生长因子-β(TGF-β)诱导的成年小鼠脾细胞向免疫球蛋白A(IgA)转换的染色体外环状DNA，并鉴定了转换重组子的断裂点。我们的结果支持这样一种假设，即转化生长因子-β增加了到IgA的开关重组事件的发生频率，并且到IgA的开关重组通常是通过裂解重组进行的。然而，在IL-2刺激恢复细胞增殖的过程中，转化生长因子-β诱导的类转换重组发生了改变。开关α区的所有断裂点都位于本研究中完成的4.2kb重复区的共同序列子集内。

We have characterized extrachromosomal circular DNAs from adult mouse spleen cells that were induced to switch to immunoglobulin A (IgA) with bacterial lipopolysaccharide (LPS) and transforming growth factor beta (TGF-beta), and identified breakpoints of switch recombinants. Our results support the hypothesis that TGF-beta increases the frequency of switch recombination events to IgA and that the switch recombination to IgA often proceeds by siccessive recombination. However, TGF-beta induced class switch recombination was modified during the cell proliferation restored by IL-2 stimulation. All the breakpoints of the switch alpha region were located within the consensus sequence subsets of the 4.2 kb repetitive region completed in this study.