Nat. Immunol. 16, 170–177 (2015); published online 15 December 2014; corrected after print 27 February and 8 April 2015

In the version of this article initially published, affiliation 3 was incomplete. The correct affiliation 3 is as follows: Graduate Program in Immunology, Department of Immunology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. The Acknowledgements section was also incomplete. The “Supported by” statement should end “...and the Thailand Research Fund through the Royal Golden Jubilee Ph.D. Program (S.S. and J.M.).” The error has been corrected in the HTML and PDF versions of the article.