Nat. Immunol. 13, 170–180 (2012); published online 25 December 2011; corrected after print 12 July 2013
In the version of this article initially published, the second affiliation for Stephanie C. Ganal is missing. This author is also affiliated with the Spemann Graduate School of Biology and Medicine, Freiburg, Germany. The error has been corrected in the HTML and PDF versions of the article.
The online version of the original article can be found at 10.1038/ni.2194