Effect of short-term cytokine stimulation on expansion of murine CFU-Meg (Panel A) and CFU-GM (Panel B). Adherent cell-depleted murine marrow mononuclear cells were exposed to cytokines for 36 hours as detailed in the text. Panel A: (A) CFU-Meg colonies (mean ± SD) derived from cells (10⁴) cultured immediately; (B) CFU-Meg colonies (mean ± SD) derived from cells (10⁴) cultured serum-free for 36 hours in presence of (TPO + KL + IL-1α + IL-3); (C) CFU-Meg colonies (mean ± SD) derived from cells (10⁴) cytokine stimulated before cryopreservation; (D) CFU-Meg colonies (mean ± SD) derived from cells (10⁴) cytokine stimulated after thawing. Data are pooled from three independent experiments, each performed in quadruplicate. Panel B: (A) CFU-GM colonies (mean ± SD) derived from cells (10⁴) cultured immediately; (B) CFU-GM colonies (mean ± SD) derived from cells (10⁴) cultured serum-free for 36 hours in presence of (TPO + KL + IL-1α + IL-3). Data are pooled from three independent experiments, each performed in triplicate.