The molecular events that initiate lymphoid-lineage specification remain unidentified because the stages of differentiation during which lineage commitment occurs are difficult to characterize. We isolated fetal liver progenitor cells undergoing restriction of their differentiation potential toward the T cell–innate lymphoid cell lineage or the B cell lineage. Transcripts that defined the molecular signatures of these two subsets were sequentially upregulated in lympho-myeloid precursor cells and in common lymphoid progenitor cells, respectively, and this preceded lineage restriction; this indicates that T cell–versus–B cell commitment is not a binary fate 'decision'. The T cell–bias and B cell–bias transcriptional programs were frequently co-expressed in common lymphoid progenitor cells and were segregated in subsets biased toward T cell differentiation or B cell differentiation, after interleukin 7 (IL-7) signaling that controlled the number of progenitor cells engaging in T cell differentiation versus B cell differentiation.

中文翻译：

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异步谱系启动决定胎儿肝中对T细胞和B细胞谱系的承诺

尚不清楚启动淋巴谱系规范的分子事件，因为难以确定谱系定型发生的分化阶段。我们分离了胎儿肝祖细胞，它们受到向T细胞固有淋巴样细胞系或B细胞谱系分化潜能的限制。定义这两个子集的分子标记的转录本分别在淋巴细胞-髓样前体细胞和普通淋巴样祖细胞中被上调，而这先于谱系限制。这表明，T细胞对B细胞的承诺并不是二元命运的“决定”。