Correction to: Nature Immunology https://doi.org/10.1038/ni.3371, published online 15 February 2016.

In the version of this article initially published, in the Acknowledgements, the grant number for the Start Grant TWILIGHT awarded to M.A.L. by the European Research Council was omitted. The correct wording is “Supported by...the European Research Council (...Start Grant TWILIGHT (637801) to M.A.L.).” The error has not been corrected in the original article.