Human Bone Marrow Contains Mesenchymal Stromal Stem Cells That Differentiate In Vitro into Contractile Myofibroblasts Controlling T Lymphocyte Proliferation

Figure 1

Biological characteristics of MSC cultured in 2D. (a) Amplified cells were fixed in the culture wells with 1% PFA in PBS, permeabilized with ice-cold absolute methanol, and labeled with anti-αSMA. Left panel: polarized light (scale bar is 150 μm), right and lower panel: fluorescence (scale bar is 100 and 20 μm, resp.). Original magnification 10x and 40x for top and lower panels, respectively. (b) Cultures were trypsinated before staining with various antibodies and flow cytometry analysis. Black profile: specific staining, gray profile: isotype control. Data for (a) and (b) are representative of 11 experiments. (c) Left panel: kinetics of kyn production by γ-IFN-stimulated MSC in IMDM medium (initial (tryp) 80 μM). One single add-on of 500 U/ml of γ-IFN was done on day 0. Supernatants were collected at the indicated time points and kyn titers were measured. Data of one experiment, representative of 3. Right panel: effect of tryp concentration upon T cell proliferation. Freshly purified, CFSE-labeled T lymphocytes were incubated with a3-28 for 5 days in tryp-free RPMI medium complemented with 0 to 20 μM of tryp, and proliferation was assessed by CFSE dilution. T lymphocyte proliferation is expressed as the inverse of the median CFSE fluorescence observed at the end of the cultures. Data of one experiment, representative of 2. Error bars are SD.

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