Cumano A, Furlonger C, Paige C J
Wellesley Hospital Research Institute, Toronto, ONT Canada.
Proc Natl Acad Sci U S A. 1993 Jul 15;90(14):6429-33. doi: 10.1073/pnas.90.14.6429.
The embryonic sites in which progenitors of the hematopoietic lineages first emerge are ideal regions to characterize both the cells and environment needed to initiate blood cell development. For a number of years both the murine yolk sac and embryo have been recognized to contain progenitors of B lymphocytes. However, clonal, quantitative in vitro assays, which allow precise observation of precursors and their progeny, have been lacking. Moreover, the site of origin of the initial events remains controversial. In this report we document the presence of B-cell progenitors in yolk sac and embryonic tissue obtained from mouse fetuses beginning at the 10-somite stage, day 8.5. We determine the frequency, cell-surface phenotype, and growth properties of these progenitors. We show that these cells can differentiate into immunoglobulin-secreting cells and that the progeny derived from single progenitors are diverse with respect to immunoglobulin heavy-chain allotype expression, diversity-joining region use, and heavy-chain variable-region utilization.
造血谱系祖细胞最初出现的胚胎位点是表征启动血细胞发育所需的细胞和环境的理想区域。多年来，人们已经认识到小鼠卵黄囊和胚胎中都含有B淋巴细胞祖细胞。然而，一直缺乏能够精确观察前体细胞及其后代的克隆性、定量体外分析方法。此外，初始事件的起源位点仍存在争议。在本报告中，我们记录了从第10体节期（第8.5天）开始的小鼠胎儿的卵黄囊和胚胎组织中存在B细胞祖细胞。我们确定了这些祖细胞的频率、细胞表面表型和生长特性。我们表明，这些细胞可以分化为分泌免疫球蛋白的细胞，并且来自单个祖细胞的后代在免疫球蛋白重链同种异型表达、多样性连接区使用和重链可变区利用方面存在差异。
