05). This result was confirmed by five SB525334 independent tests (Figure 3). The 3T3 cell line was used as a control, and no effects on cell cycle were observed (70.3 ± 3.1% in G0/G1 and 27.3 ± 5.1% in S, respectively (compared with PHA stimulated T cells, p > 0.05). These results suggested that the inhibitory effect of CML-derived MSCs on cell cycle arrest was also impaired. Figure 3 Effects ofMSCs on

T cell cycle. Flk-1+CD31-CD34- MSCs or 3T3 at 1:10 ratios (MSCs to T cells); the data are expressed as mean ± S.D. Of triplicates of five separate experiments with similar results. Cell cycles of PHA-stimulated T cells were analyzed in T cells alone (Ts), cocultured with MSCs (MSC + Ts) group andMSCs derived from CML patient group (CML MSC + Ts). 3T3 cell line was used as control (3T3 + Ts). Data are shown as means ± S.D. of five independent experiments (*p ≥ 0.05, **p < 0.05 vs. Ts) selleck inhibitor impaired effects of MSCs on T cell activation MSCs from CML patients could significantly inhibit activation of T cells. The percentage CP-868596 cell line of CD25, CD69 and CD44 in PHA induced T lymphocyte was 12.3 ± 3.5%, 34.5 ± 5.9% and 29.4 ± 7.0% respectively. But they were 3.1 ± 2.3%, 6.4 ± 3.2% and 2.1 ± 1.7% when co-cultured with normal hemangioblasts and, when co-cultured with CML hemangioblasts, they were 5.4 ± 2.3%, 31.5 ± 6.8% and 24.5 ± 3.6%

respectively. All data presented here were confirmed by repeated tests (Figure 4). These results also indicated that MSCs from CML patients were impaired in their immuno-modulatory function. Figure 4 Effects of Flk-1+CD31-CD34- MSCs on T lymphocyte activation.

Flk-1+CD31-CD34- MSCs at 1:10 ratios (MSCs to T cells); the data are expressed as mean ± S.D. of triplicates of five separate experiments with similar results. Activators of T cells were analyzed including CD25, CD69, and CD44. The activation of T cells was analyzed in T cells alone (Ts), normal MSC cocultured with activated T cells (BMSC + Ts), and CML-derived MSC cocultured with activated T cells (MDS MSC + Ts). Data are shown as means ± S.D. of five independent experiments Megestrol Acetate (*p ≥ 0.05,**p < 0.05 vs. Ts) Dampening effect of MSCs on T cell apoptosis In apoptosis tests, we have observed that MSCs from healthy volunteers could significantly dampen the effect of activation-induced apoptosis of T cells. Following stimulation with PHA for 3 days, the rate of apoptosis of T cells was 23.37 ± 2.71%. When PHA-stimulated T cells were cocultured with MSCs obtained from healthy volunteers, the percentage of apoptotic T cells decreased to 14.1 ± 0.65% (compared with PHA stimulated T cells, p < 0.05). In the same condition, the apoptosis percentage of T cells co-cultured with MDS-derived MSCs further decreased to 8.36 ± 1.31% (compared with co-culture systemof normalMSCs, p < 0.05). We repeated the experiment five times to confirm this result (Figure 5).