Phenotypic characterization of early lymphoid progenitors in humanized mice. (A-B) Gating procedures. Irradiated NSG mice were injected intravenously with CD34⁺ HPCs (1.5 × 10⁵ cells), and the BM and thymus were harvested 8 weeks later. Single-cell suspensions obtained from 3 mice were pooled and labeled with the corresponding antibodies. Gates are set on human CD45⁺ cells. (A) CD34⁺⁺ BM cells were sorted based on CD7 and CD10 expression. (B) Thymocytes were sorted based on CD7, CD4, and CD8 expression. The corresponding cell populations were then analyzed by qRT-PCR. (C) qRT-PCR analysis of sorted CD34⁺CD7⁻CD10⁻ and CD34⁺CD7⁺CD10⁻ BM HPCs, and of CD7⁺CD4⁻CD8⁻ and CD7⁺CD4⁺CD8⁺ thymocytes of recipient mice 8 weeks after grafting (see also supplemental Figure 5B). Expression levels are normalized relative to those detected in total nonfractionated BM CD34⁺ HPCs. For BM cells, results are means ± SD of 2 independent experiments. For thymocytes, results are from one experiment.