Figure 5.

Intracellular calcium mobilization and extracellular signal-regulated kinase (ERK) activation events were involved in naturla killer (NK) cell-mediated xenoreactive cytotoxicity. (a) Interleukin-2 (IL-2) -activated human primary NK cells were pre-incubated with designated monoclonal antibodies (mAbs). Calcium flux was measured as described in the Materials and methods. MPN3 cells and ionomycin were inoculated at the times indicated by arrows. Each line represents intracellular calcium concentration from a single cell in a given microscopic field. The data are representatives of five independent experiments. (b) A standard ⁵¹Cr-release assay was performed with IL-2-activated human primary NK cells as effector cells and MPN3 cells as target cells. EGTA at designated concentrations was added to NK cells during cytotoxicity assay. Specific lysis (%) was presented as mean + SD of triplicates. The data are representatives of minimum three independent experiments.