The Potential Role of Quorum Sensing in Clonal Growth and Subsequent Expansion of Bone Marrow Stromal Cell Strains in Culture

Figure 2

Clonal growth depends on serum. Samples of clonal nucleated cells from unsorted human BM were plated and cultured in 100 mm dishes ( cell/cm², ). Photographs of culture dishes showing proliferation of primary BM CFU-F, cultured in standard CFU-F growth medium supplemented with 20% FBS (a) or cultured in SDM and supplemented with EGF/PDGF (10 ng/ml) (c). After 2 weeks of culture, well-developed colonies were observed in serum-supplemented cultures (a, b). In contrast, no colony developed in SDM; single cells remained attached with an intact nucleus and an intact cytoplasm (arrows), for at least 2 weeks, as demonstrated by Giemsa staining, but did not proliferate or generate any clone in serum-free medium (c, d). Results are derived from 5 independent experiments and from 5 different donors. FBS: Fetal Bovine Serum; EGF: Epidermal Growth Factor; PDGF-BB: Platelet-Derived Growth Factor. Scale bars represent 50 μm, 100 μm, and 200 μm.