Collective dynamics of natural killer cells interacting with cancer and fibroblast cells.

Natural killer cells (NKCs) can distinguish the difference between normal and abnormal cells, and kill the latter. Nevertheless, regardless of the past intensive studies on the intracellular crosstalk via extracellular vesicles, the generic dynamical behaviors of the NKCs around its co-cultured cells in their attacking process remains an elusive intriguing issue. Here, using the binary mixtures of NKCs and normal fibroblast/cancer cells, we experimentally reveal the above unexplored issue. It is found that, NKCs initially assess and identify the type of co-cultured cells. For cancer cells, NKCs attach to them, recruit neighboring NKCs to form clusters, and exhibit anchored fluctuating motion around the cancer cells in the killing process, until the death of cancer cells. In response, CCs also aggregate into larger clusters than those of the NKC free case, until their death, to avoid NKC attacking. In contrast, when interacting with normal fibroblasts, NKCs continuously scout around the cells, without forming large clusters. They cause little effect on fibroblast motion.