Nat. Immunol. 11, 561–564 (2010); published online 18 June 2010; corrected after print 25 June 2010

In the version of this article initially published, the affiliation provided was incorrect. It should read as follows: “Kevin J. Tracey is with the Center for Biomedical Science, Feinstein Institute for Medical Research, Manhasset, New York, USA.” The error has been corrected in the HTML and PDF versions of the article.