CD38 is a cytotoxic trigger in YT CD16⁺ and NKL CD16⁺ cells.

Target cells used in the redirected cytotoxicity experiments were the murine mastocytoma P815 (A) and the human erythroleukemia K562 (B) lines, selected because both express FcRγ. The cells were labeled with ⁵¹Cr, washed, and incubated with RaMIg (5 μg/mL) for 30 minutes at 4°C. Anti-CD16 and anti-CD71 mAbs and the medium alone were used as relevant and irrelevant controls, respectively. Solid bars show the percentage of cytotoxicity on triggering of CD16⁺YT cells and the CD16⁺ variant of the NKL cells. YT mock cells and the NKL CD16⁻ variants (open bars) were also included. The untransfected wild-type YT cell line showed the same behavior as the YT mock cells. Vertical bars represent the mean ± SD results from 6 independent experiments.