title: Bystanders not so innocent after all.
abstract: Interleukin 27 (IL-27) regulates immune responses, including T helper 17 (Th17) cell activity. In this issue of Immunity, Hirahara et al. (2012) demonstrate that IL-27 suppresses Th17 cells in trans through induction of the inhibitory ligand PD-L1 on bystander T cells.
authors: Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW 2010, Australia.
authors: Marcel
authors: M
authors: Batten
authors: Nico
authors: N
authors: Ghilardi