To clear infection, cytotoxic lymphocytes must destroy target cells while avoiding nonspecific killing of surrounding healthy cells. In this issue, Hsu et al. (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201604136) use live-cell imaging to show that lytic granule convergence protects bystander cells from unintended death by promoting polarized secretion of soluble cytolytic proteins toward the intended target.
© 2016 Ritter and Mellman.