Figure 2From: Pathogen-free, plasma-poor platelet lysate and expansion of human mesenchymal stem cells Experiments of MSC induced immunosuppressive activity. CSFE dilution profile of stained responder (R) cells in MLC cultured without MSC (a) and with MSC, with R cells to MSC ratio of 20/1 (R/MSC 20/1) (b). M1 is the peak of cells not proliferating, M2 is the peak of 1st daughter proliferating cells and M3 is the peak of 2nd daughter proliferating cells. c) Percentage of R proliferating cells in MLC moving respectively to 1st and 2nd daughter generations either in absence or in presence of different MSC concentrations, in a representative experiment. d) Inhibition of cell proliferation in MLC expressed as percentage of study R cells (co-cultured with MSC) not moving from 1st daughter to 2nd daughter generation, compared to control R cells (cultured without MSC; see also methods). The experiments were performed using PL1- and PI-PL1derived MSC3, PL2- and PI-PL2-derived MSC8, PL3- and PI-PL3-derived MSC8. PBMC used as R cells in MLC were also co-cultured at R/MSC 20/1 without stimulator cells with PHA at a concentration of 50 μg/ml. Data show that with a ratio of R cells to MSC of 20/1 (R/MSC 20/1) the highest cell proliferation inhibition was observed, without any significant difference among MSC populations (as judged by two-tailed paired Student’s T test, specifically applied to assess differences between PL- and PI-PL-derived identical MSC populations). Cultures carried out in the presence of PHA produced less inhibition for any MSC population than the corresponding MLC at R/MSC 20/1. MSC, mesenchymal stem cells; R, responder cells; S, stimulator cells; MSC 50000 corresponds to R/MSC 20/1, MSC 100000 to R/MSC 10/1, MSC 200000 to R/MSC 5/1.Back to article page