Take a culture of cancer cells with fluorescently labeled cytoplasmic proteins.
Add cytokine-induced killer or CIK cells — effector T cells with natural killer cell-like characteristics — possessing anti-tumor activity.
Natural killer group 2 member D or NKG2D receptors on the CIK cells bind to stress-inducible proteins on the cancer cells.
The binding induces CIK cells to release cytoplasmic granule toxins — perforins and granzymes.
Perforins form pores in the cancer cell membrane, allowing the entry of granzymes, which activate caspases, inducing apoptosis.
Post-incubation, harvest the cells. Add a fluorescent nucleic acid-binding cell viability dye.
The dye enters through the damaged cell membrane and binds to DNA, resulting in dual-stained dead cells.
With an intact cell membrane, live cells are impermeable to the dye.
Pass the cells through a flow cytometer to detect live cells displaying single fluorescence and dead cells with dual fluorescence.
Create a scatter plot to measure the percentage of dead cancer cells, quantifying the cytotoxic effect of CIK cells.