Seeking broad protection As scientists develop therapeutic antibodies and vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the risk of emergent coronaviruses makes it important to also identify broadly protective antibodies. Wec et al. isolated and characterized hundreds of antibodies against the viral spike protein of SARS-CoV-2 from the memory B cells of a survivor of the 2003 outbreak caused by the related coronavirus, SARS-CoV. In both of these viruses, the spike protein facilitated viral entry by binding to the angiotensin-converting enzyme 2 (ACE2) receptor on human cells. The antibodies targeted multiple sites on the spike protein, but of nine antibodies that showed strong cross-neutralization, eight targeted the domain that binds to ACE2. These eight antibodies also neutralized a bat SARS-related virus. Illuminating the epitopes on the viral spike protein that bind cross-neutralizing antibodies could guide the design of broadly protective vaccines. Science , this issue p. 731