IMMUNOGLOBULIN GENES IN DIFFERENTIATING B CELLS

免疫球蛋白（IG）基因结构的一系列重要变化 发生在B细胞发育过程中。 完全变量（V）的形成 编码重链（H）和轻链（H）的恒定区（C）的5'区 链蛋白和随后的连接的V-H区与C-H C区3'（重链转换）通过重组发生， 机制等 然而，由于这些事件在时间上是不同的， 不同的识别序列，不同的重组系统， 可能在每种情况下使用。 到目前为止，我们的大部分信息， B过程中H链转换的机理及其时机 细胞分化来自骨髓瘤和少数B细胞的研究 肿瘤的 我们最近开发了一个模型系统来研究IG基因结构， 使用逆转录病毒Abelson病毒分化成熟B细胞。 利用这种方法，我们已经开发了一系列克隆的，永生化的， 非致瘤性mIgM和IgG阳性B细胞系。 不同分离株 合成各种H和L链同种型，一些分离株分泌IG。 这些细胞的独特性质和它们执行关键任务的能力 B细胞发育中重组步骤使它们成为理想的模型系统 研究B过程中缺失转换的时间和机制 细胞分化

A series of important changes in the structure of immunoglobulin (Ig) genes occurs during B cell development. Both formation of complete variable (V) regions 5' of the constant (C) regions encoding both heavy (H) and light chain proteins and the subsequent linkage of the V-H region with C-H regions 3' of C (heavy chain switching) occur by recombinatorial mechanisms. However, because these events are temporally distinct and use different recognition sequences, different recombinatorial systems are probably used in each case. To date, most of our information concerning the mechansim of H chain switching and its timing during the course of B cell differentiation has come from studies of myelomas and a few B cell tumors. We have recently developed a model system to study Ig gene structure during differentiation of mature B cells using the retrovirus Abelson virus. Using this approach, we have developed a series of clonal, immortalized, nontumorigenic mIgM and IgG-positive B cell lines. Different isolates synthesize various H and L chain isotypes and some isolates secrete Ig. The unique nature of these cells and their ability to carry out a key recombinatorial step in B cell development make them an ideal model system to study both the timing and the mechanism of deletional switching during B cell differentiation.