Study maps crucial component of long-term immune response to SARS-CoV-2 Researchers in the United States have found that protective antibodies generated against the original strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)– the agent that causes coronavirus disease 2019 (COVID-19) – also protect against viral variants. Monoclonal antibodies derived from memory B cell reserves in convalescent individuals competed to bind the spike protein of both the original SARS-CoV-2 strain and variant strains. The spike protein is the main surface structure the virus uses to bind to and infect host cells. Duane Wesemann from Harvard Medical School in Boston and colleagues say the study maps a crucial component of the long-term immune response to SARS-CoV-2 infection.