David Veesler investigates infectious diseases with a focus on understanding, controlling, and combating cross-species transmission, or spillover, of pathogens to humans. Veesler and his team use structural and immunological approaches to study antibody responses to viruses in bats – known reservoirs for zoonotic transmission. Specifically, they pinpoint viruses with no or few barriers to replication in humans, with hopes of assessing the likelihood of spillover events. They are also investigating the bat humoral immune response as a potential untapped source of viral inhibitors. Additionally, the team studies SARS-CoV-2 infection and vaccination in humans; for example, they identified ACE2 as the SARS-CoV-2 receptor and unveiled the architecture of the viral spike protein.