Dynamic visualization of the whole process of cytotoxic T lymphocytes killing B16 tumor cells in vitro

Cytotoxic T lymphocytes (CTLs) play a key role in adoptive cell therapy (ACT) by destroying tumor cells. Although some mechanisms of CTLs killing tumor cells have already been revealed, the precise dynamic information of CTLs' interaction with tumor cells is still not known. Here, we used confocal microscopy to visualize the whole process of how CTLs kill tumor cells in vitro. According to imaging data, CTLs destroyed the target tumor cells rapidly and efficiently. Several CTLs surrounded one or more tumor cells, and the average time for CTLs destroying one or more tumor cells in vitro is dozens of minutes only. Our study displayed the temporal events of CTLs' interaction with tumor cells at the beginning up to the point of killing them. Furthermore, the imaging data presented strong cytotoxicity of CTLs toward the specific tumor cells. These results could help us to well understand the mechanism of CTLs' elimination of tumor cells and improve the efficacy of ACT in cancer immunotherapy.