ALDH^br CD34⁺, ALDH^neg CD34⁺, and ALDH^br CD34^neg cells derived from UCB. UCB cells were labeled with BAAA, as described in “Materials and methods.” (A) Background fluorescence was established in the presence of DEAB. (B,E) SSC^lo ALDH^neg and SSC^lo ALDH^br cell fractions were defined. (C-D) Both cell fractions contained CD34⁺ cells, although the SSC^lo ALDH^br fraction was highly enriched for CD34⁺ cells, to include CD34⁺ CD38^neg cells (n = 8) (D). In most developmental studies, cells expressing lineage-specific antigens were excluded (n = 25). (F) CD34⁺ lin^neg cells were isolated from the SSC^lo ALDH^neg. (G) CD34⁺ lin^neg and CD34^neg lin^neg cells were isolated from SSC^lo ALDH^br UCB (H-M). To ensure purity, each cell fraction was sorted twice. Representative reanalyses depict twice-purified lin^neg SSC^lo ALDH^neg CD34⁺ cells (H,K), lin^neg SSC^lo ALDH^br CD34^neg cells (I,L), and lin^neg SSC^lo ALDH^br CD34⁺ cells (J,M).