To illustrate the functional mimicry discovered in antibodies to the SARS coronaviruses, a mime holds in his hand SARS-CoV S bound to the ACE2 receptor (teal). His reflection shows a SARS-CoV S bound to the neutralizing antibody fragment S230 (purple). Coronaviruses that cause deadly atypical pneumonia worldwide enter target cells via membrane fusion upon binding of the viral spike (S) glycoprotein to a host receptor. In the Jan. 31, 2019, edition of Cell, a research team led by Alexandra Walls, Xiaoli Xiong, and David Veesler of the University of Washington School of Medicine unveils the mechanisms of neutralization of SARS-CoV and MERS-CoV by two human monoclonal antibodies isolated from people who recovered from their infections. The study shows the SARS-CoV S230 antibody recapitulates the action of the host receptor (angiotensin-converting enzyme 2) by promoting fusogenic conformational changes of the S glycoprotein.