Vol. 214, No. 3, March 2017. Pages 669–680.

The Journal of Experimental Medicine regrets that due to a production error, the original version of this paper does not display the correct values in the contour plots of Fig. 5 (A and D). The legend remains correct, and the corrected figure appears below. The online HTML and PDF versions of this article have been corrected. The error only remains in the print version.