Li Y S, Wasserman R, Hayakawa K, Hardy R R
Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
Immunity. 1996 Dec;5(6):527-35. doi: 10.1016/s1074-7613(00)80268-x.
We have identified a very early stage of B lineage cells in the CD45R (B220)+CD24 (HSA) pre-pro-B fraction of mouse bone marrow delineated by expression of AA4.1, a molecule found on stem cells and early B lineage cells. These cells are B lineage precursors based on their capacity to generate B lineage cells rapidly in stromal-dependent culture and their expression of high levels of germline IgH transcripts in the absence of Rag-1/2. Half of these AA4.1+ precursors express low levels of CD4, characteristic of lymphoid progenitors, but few if any have up-regulated CD19, a molecule expressed very early in the B lineage. Furthermore, expression of genes encoding pre-B and B cell receptor components (mb-1, B29, and lambda 5) and transcription factors necessary for B lineage differentiation (BSAP, E12, E47, and Id) provide further support for designating these cells as the earliest B cell precursors.
我们已在小鼠骨髓的CD45R（B220）+CD24（HSA）前前B细胞亚群中鉴定出B淋巴细胞的一个非常早期的阶段，该阶段由AA4.1的表达所界定，AA4.1是一种在干细胞和早期B淋巴细胞上发现的分子。这些细胞是B淋巴细胞前体，这基于它们在基质依赖培养中快速产生B淋巴细胞的能力以及在没有Rag-1/2的情况下高水平种系IgH转录本的表达。这些AA4.1+前体中有一半表达低水平的CD4，这是淋巴祖细胞的特征，但很少有细胞（如果有的话）上调CD19，CD19是在B淋巴细胞系中非常早期表达的一种分子。此外，编码前B细胞和B细胞受体成分（mb-1、B29和λ5）的基因以及B淋巴细胞分化所需转录因子（BSAP、E12、E47和Id）的表达，为将这些细胞指定为最早的B细胞前体提供了进一步的支持。
