Sca-1⁺/LIN^- cells accumulate in catalase-treated LTBMCs. Nonadherent cells removed from culture each week were stained with antibodies against murine Sca-1 labeled with phycoerythrin (PE) and a lineage marker cocktail (Gr-1, Mac-1, and Ter-119) labeled with FITC. Plot showing percentage of Sca-1⁺ and lineage-negative cells at weeks 1, 2, and 3 in catalase-treated cultures (right panel) versus control cultures (left panel). The histograms shown are representative of those obtained repeatedly over a 2-year period.