. Author manuscript; available in PMC: 2019 Sep 18.
Published in final edited form as: Nat Immunol. 2019 Mar 18;20(5):602–612. doi: 10.1038/s41590-019-0342-0
Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms