The survival of G-CSF elicited peripheral blood neutrophils (87% ± 2% pure) from WT (•) and βc-null (○) mice in in vitro cultures containing (A) 3 × 10⁴ U/mL mGM-CSF (continuous line) or saline (broken line). (B) 4 × 10³U/mL mIL-3 (continuous line) or saline (broken line). Cells were placed in microtiter trays (200 cells per well) and the number of viable cells was counted in four replicate wells at various time points thereafter (hours). (C) Dose-response relationship for neutrophils from WT (•) and βc-null (○) mice in mGM-CSF, starting concentration 3 × 10⁴U/mL with fivefold dilutions. Results are the means of four wells. Error bars represent SD. One of six similar experiments.