Figure 7.

MM stroma decreases CB-NK cytotoxicity: (a) CB-NK cytotoxicity reduction after adding MM stromal cells into cytotoxicity assays. Cytotoxicity assays for MM cells were done in parallel either adding (Target cell+CB+NK+Stroma) or not adding (Target cell+CB-NK) MM stromal cells to the assay. (b) Confocal fluorescence image of stromal MM cells with CB-NK (in green with bodipy) and KMM1 MM cells (in blue with CMAC). Actin is shown in red. Stromal cells can be visualized by the actin filaments. Arrows in the lower part show CB-NK adhered to stromal cells. Arrows in the upper part show transfer of CB-NK content to MM cells and also secondarily between MM cells. The white square is shown amplified in the right side showing either two colors (CMAC and actin) or the three colors together (CMAC, bodipy and actin). Same images were confirmed for other MM cell lines. (c) CXCL12 levels in the supernatant of cytotoxicity assays with MM cells adding either stroma with target MM cells and CB-NK (Stroma+target+CB-NK) or stroma with target cells alone (Stroma+target). Serum MM patient was added as positive control. P-values represent analysis of stroma alone versus stroma+target. (d) Cytotoxicity CB-NK reduction at 20 : 1 or 10 : 1 effector:target ratio, after adding (Stroma+AMD3100) or not adding (Stroma) AMD3100 to the cytotoxicity assay with stroma, CB-NK and MM cells. *P≤0.05