A new international study led by scientists at La Jolla Institute for Immunology (LJI), The University of Liverpool and the University of Southampton is the first to give a detailed snapshot of how the body’s CD4+ T cells respond to the SARS-CoV-2 virus. Among the findings, their work suggests that early in the illness, patients hospitalized with severe cases of COVID-19 develop a novel T cell subset that can potentially kill B cells and reduce antibody production.