Correction to: Nature Immunology https://doi.org/10.1038/s41590-019-0397-y, published online 20 May 2019.

In the version of this article initially published, due to a figure preparation error, in Fig. 2b, the lower-right Day 8 image was an inadvertent duplicate of the upper-left Control image. Due to the age of the article, the figure cannot be updated directly. The corrected Fig. 2b is available as Supplementary Information alongside this amendment. This notice serves to correct the article.