FIG. 1.

Characterization of the GFP⁺ MSC population over passage. The top row illustrates the cell scatter distribution (forward scatter vs. side scatter); the middle row illustrates dual-parameter dot plots (GFP vs. FL-2), and the bottom row illustrates histograms (GFP vs. cell counts) of GFP positivity of the MSC population over passages. Freshly isolated bone marrow cells were found to be highly positive for GFP. After in vitro cell culture, however, MSCs were noted to be ∼50% GFP⁺. This 50% expression was observed to remain the same after subsequent passage (ie., there was not continued decline in expression over time or with multiple cell passage).