Natural killer (NK) cells are traditionally considered to be innate immune players. In this Review, J. C. Sun and L. L. Lanier summarize the principles of NK cell development, homeostasis and function, and draw parallels between NK cell and CD8+T cell biology. From a fascinating discussion it appears that the borders between innate and adaptive immunity are not as well defined as previously thought.
- Joseph C. Sun
- Lewis L. Lanier
