Nat. Methods 15, 17 (2018); published online 3 Jan 2018; corrected after print 7 February 2018

In the version of this article initially published, the affiliation of Leo James was incorrectly stated as Cambridge University; the correct affiliation is MRC Laboratory of Molecular Biology, Cambridge. Furthermore, the antibody receptor described was incorrectly called TRIM2; the correct name is TRIM21. The errors have been corrected in the HTML and PDF versions of the article.