Isolation and characterisation of mesenchymal stem cells derived from human placenta tissue

Figure 6 Dose dependent inhibitory effect of placenta mesenchymal stem cells on phytohemagglutinin stimulated PBMC via cell to cell contact. A: Peripheral blood mononuclear cells (5 × 10⁵ cells) with or without phytohemagglutinin (PHA) stimulation were co-cultured with various ratios of placenta mesenchymal stem cells (PLC-MSC) and incubated for 72 h. For the final 18 h of the culture, tritium thymidine (³H-TdR) was pulsed into the wells. PLC-MSC failed to stimulate proliferation of resting T cells but PLC-MSC inhibited activated T cells proliferation in a dose dependent mechanism; B: PBMC (2 × 10⁶) stimulated with PHA were also co-cultured with 2 × 10⁵ PLC-MSC (direct and indirect contact) and MSC conditioned media in a 12 well plate. T cells were harvested after 48 h of incubation, plated in 96-well plates and proliferation was measured by ³H-TdR on day 3. This result represents the average percentage of T cell proliferation ± SD of 3 repeated experiments. ^aP < 0.05 vs positive control (T + PHA).