Interaction with Mesenchymal Stem Cells Provokes Natural Killer Cells for Enhanced IL-12/IL-18-Induced Interferon-Gamma Secretion
Figure 5
MSC stimulate the phosphorylation of STAT4 in NK cells. NK92 cells (a and b) and primary NK- (pNK) cells (c and d) were cultured in the absence or presence of MSC at a NK : MSC ratio of 5 : 1. Cells were preincubated for 24 h prior to stimulation with IL-12 (1 ng/mL) and IL-18 (10 ng/mL). Sixteen hours after stimulation, cells were stained with antibodies against CD56 and intracellular pSTAT4 (phosphorylated STAT4). Intracellular pSTAT4 levels were determined by flow cytometry. ((a) and (c)) Dot plots of one representative experiment. ((b) and (d)) Bar graph shows mean values ± standard deviation of 4 (b) and 6 (d) independent experiments performed using (b) 4 different donors for MSC and (d) 3 and 4 different donors for MSC and pNK cells, respectively. Data are normalized and presented as percentage of pSTAT4 positive NK cells cultured in the presence of MSC with respect to NK cells cultured alone (100%). .
