K cells

例句：

1. 1.The immune system relies on K cells to fight off infections.
   免疫系统依赖于K细胞来抵抗感染。
2. 2. In cancer research, K cells are used to target and destroy cancer cells.
   在癌症研究中，K细胞被用来靶向并摧毁癌细胞。
3. 3. The study of K cells has led to breakthroughs in vaccine development.
   对K细胞的研究已经导致了疫苗开发的突破。