Nature Immunology; 10, 655–664 (2009); published online 17 May 2009; corrected after print 18 May 2009

In the version of this article initially published, some of the funding was stated incorrectly or missing; the Competing Financial Interests section was missing; and the citation to reference 15 was missing. The correct funding statement should be as follows: Supported by the Wellcome Trust (085096 to J.A.S.), the New York University School of Medicine (J.A.S.), the US National Institutes of Health (R37 AI32524 to D.G.S.; R01 GM086852A to J.A.S.; R01 CA125195 to C.H.B.; and RO1 AI050737 to M.A.F.), the Pew Scholars Program (C.H.B. and M.A.F.), the Cancer Research Institute (M.A.F.), the Cancer Research Institute Predoctoral Emphasis Pathway in Tumor Immunology (B.Y.), Boehringer Ingelheim (M.B.), Genome Research in Austria (M.B.) and the Howard Hughes Medical Institute (D.G.S.). The correct Competing Financial Interests statement should be “The authors declare competing financial interests”; in the PDF, the statement also includes “details accompany the full-text HTML version of the paper at http://www.nature.com/natureimmunology/.” The citation for reference 15 should be on the first page as follows: “Studies of the rearrangement status of Igh alleles in mature B cell hybridomas and in developing B cells that have been transformed by Abelson murine leukemia virus15 have suggested....” The errors have been corrected in the HTML and PDF versions of the article.