Fig. 1. Isolation of three categories of lymphoid progenitors.

As detailed in the Materials & Methods, bone marrow suspensions were depleted of lineage positive cells and then sorted as early lymphoid progenitors (ELP; Lin^– Sca1⁺ cKit^Hi RAG-1/GFP⁺), L-selectin⁺ progenitors (LSP; Lin^– Sca1⁺ cKit^Hi Thy1.1^– L-selectin⁺) and common lymphoid progenitors (CLP; Lin^– Sca1^Lo cKit^Lo Thy1.1^– IL7R⁺). All parameters matched the originally described characteristics of these progenitors, and typical post-sort purities are shown. In some experiments, cells were subjected to two rounds of sorting and biological activities were indistinguishable.