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

Figure 3

Social conditions on CFU-F growth. (a) To assay for secondary CFU-Fs, samples of nucleated cells from primary BM-MSC cultures were plated and cultured either in 100 mm dishes (density at 1.6 cells/cm², where cells are physically isolated in a common environment: “social conditions”; A) or in 96-well plates at cloning dilution (where single cells are in single wells: physical and biochemical “isolation”; B) in FBS-supplemented culture medium. No differences (C) were observed between numbers of BM-MSC colonies either in “isolation” (number of CFU-Fs) or under “social” conditions (number of CFU-Fs). (b) Flow cytometric analysis of a multiclonal strain obtained by combining multiple primary colonies. No significant (NS) differences were observed between BM-MSCs obtained by combining multiple primary colonies from “social conditions” (A) or “isolation conditions” (B). Note the high/bright expression of multiple markers of BM-derived CFU-Fs (and “mesenchymal stem cells”), CD73, CD90, and CD105 and low expression of HLA-ABC. Endothelial (CD34) and hematopoietic markers (CD45, HLA-DR) are negative. Results are expressed as the (). . Results are derived from 5 independent experiments and from 3 different donors. FL: Fluorochrome; FSC: Forward Scatter.

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