In the version of this article originally published, the statistic described in Fig. 3d was incorrect. It was described as P < 22 × 10-16. It should have been P < 2.2 × 10-16. Also, the CD8+ Treg label in Fig. 4f was incorrect. It should have been CD4+ Treg. The errors have been corrected in the HTML and PDF versions of this article.