The analysis of lymphoid cell differention by using cell lines transformed with a ts mutant of Abelson murine leukemia viurs.

我们已经成功地获得了Abelson小鼠白血病病毒（a - mulv）的ts突变体，通过生物学试验依赖于B淋巴瘤在允许和非允许温度下分化状态的变化。采用骨髓集落法、焦点法和ts病毒原病毒DNA基因转染法分析病毒活性。结果证实，该病毒具有突变病毒的特性。通过使用ts突变体ts-49，我们建立了几个未成熟B淋巴瘤，以分析免疫球蛋白（Ig）在分化过程中的表达机制。我们观察到2)在Ig重排之前，VH基因连接到D@j片段的使用是预先确定的；2)在前b细胞阶段合成的u链作为与未知分子相关的链在细胞表面表达。目前尚不清楚这种现象是否仅存在于已建立的淋巴瘤中，然而，该分析提供了关于Ig基因表达编程的新信息，与已有的观点相反，即VH基因是随机选择的，并在Ig基因重排阶段用于VDJ加入。另一方面，我们已经建立了一个新的系统，通过转化病毒，包括its突变体转化胎儿胸腺淋巴样细胞。利用这个新系统，我们观察到B前体在胎儿胸腺中储存的频率很高。胎儿胸腺有活动。储存胎肝来源的B前体，并支持胸腺和胎肝来源的前B淋巴瘤的产生和存活。这一结果为胸腺基质在B细胞发育中的作用提供了新的认识。此外，我们还建立了未成熟的T细胞系；一个是“双阴性”，CD3+，和]阳性细胞，另一个是Thy-1+，AA4.1+, IL2R+。后者可能属于未成熟的T系细胞，这在文献中是已知的。

We have succeeded in obtaining a ts mutant of Abelson murine leukemia viurs(A-MuLV) through a biologikal assay relying on changes in the differentiation state of B lymphomas at permissive and nonpermissive temperatures.The viral activity was further analysed by bone marrow colony assay, focus assay,and gene transfection assay using proviral DNA of ts virrus. The results confiem that the virus carries theproperty of a ts mutat virus.By using this ts mutant,designated as ts-49,we have established several immature B lymphomas to analyse the mechanism of immunoglobulin(Ig) expression during differentiation. We observed 2)the usage of a VH gene to join toa D@j segment was predetemined prior to the Ig rearrangement,2) u chains, synthesized at the stage of pre-B cells,were expressd on the cell surface as an associated from with unknown molecule(s).It is not known whether the phenomena are only peculiar to established lymphomas,however,the analysis provides new information about the programming of Ig gene expression,in contrast to the esteblished view that VH genes are rendomely selected and used for VDJ joining at the stage of Ig gene rearrangement.On the other hand,we have established a new system to transform lymphoid cells in fetal thymus by transforming viruses including a ts mutant.By using this new system,we observed that B precursors were stored at high frequency in fetal thymus.Fetal thymus carries activity. to store B precursors of fetal liver origin and to support the generation and survivals of pre-B lymphomas of thymic and fetal liver origin.This result leads new insight about the role of thymic stromas on B cell development.In addition,we have establishd immature T cell lines;one is "double negative",CD3+,and]positive cell and antogher is Thy-1+,AA4.1+, IL2R+.The latter may belong toimmature T lineage cells which are nou known in the literature.