FIGURE 1.

The effect of DBMSCs on NK cell proliferation. (A) The proliferation of resting non-activated cells (NK cells were induced to proliferate by 100 U/mL IL-2) was significantly decreased in presence of DBMSCs relative to untreated resting non-activated NK cells, at all ratios shown except for the 1NK:1DBMSC ratio. (B) IL-2-activated NK cell proliferation significantly increased at the 1NK:1DBMSC ratio in the presence of DBMSCs relative to untreated IL-2-activated NK cells. NK cells were initially activated by 100 U/mL IL-2 for 72 h. Results of 10 representative experiments are shown, in which the proliferation of resting non-activated or IL-2-activated NK cells cultured for 72 h, with or without Mitomycin C-treated DBMSCs, was measured at the NK: DBMSC ratios of 1:1, 15:1, 25:1, 50:1 and 100:1, using the MTS proliferation method. Experiments were performed in triplicates using NK cells and DBMSCs prepared from the peripheral blood of 10 healthy subjects and 10 normal human full-term placentae, respectively. Bars represent standard errors, *P< 0.05.