G-CSF and CD137 protein induce proliferation and survival of bone marrow cells.

<p>Murine bone marrow cells at a density of 10⁶ cells/ml were cultured for 7 days with respective treatment. 10 µg/ml of Fc or CD137-Fc protein were pre-coated on the plates. (A) Proliferation assay: 1 ng/ml of G-CSF was added daily to indicated wells. Cells (10⁵/condition) were labeled for the last 24 h with 0.5 µCi ³H-thymidine, and the rate of proliferation was determined with a scintillation counter (Packard, Meriden, CT). Depicted are means ± standard deviations of triplicate measurements. (B) Cell count: 10 ng/ml of G-CSF was added daily to indicated wells. Cells (2×10⁶/condition) were harvested on day 7, and cell count was determined by trypan blue staining of 4 representative microscopic fields. Depicted are means ± standard errors of seven independent experiments. * p<0.05; ** p<0.01.