Sorting of Fas⁺ and Fas^- candidate HSCs. CD34⁺ CB cells were cultured in SF medium supplemented with SFT3 for 5 days before being stained with FITC-conjungated antilineage Abs (CD3, CD14, CD15, CD19, CD20, CD56, CD66b, and glycophorin A), anti-Fas–PE, and anti-CD34–APC. Lin^-Fas^- and Lin^-Fas⁺ cells were sorted on a FACSVantage and analyzed for purity as indicated (numbers in parenthesis indicate purity of sorted populations with regard to Fas expression). One experiment representative of 3 is shown.