Exposure to SARS-CoV-2 by infection or vaccination generates immune cells that provide long-term immunity. These long-lived memory T cells play a key role in preventing severe cases of Covid-19. Researchers at the University of Zurich have now discovered how these memory T cells form.
Many questions about how exposure to SARS-CoV-2 by infection or immunization might result in long-term protective immunity remain unanswered. Onur Boyman, head of the Department of Immunology, and his research team at the University of Zurich and the UniversityHospital Zurich have now taken a closer look at how this long-lived protection is formed. Together with researchers from ETH Zurich, they identified specific signaling pathways that determine when immune cells develop into so-called memory T cells.
The study helps to unravel the complex way in which immunological memory to SARS-CoV-2 is – or is not – formed and maintained. While some infections result in robust and long-lasting T cell memory, others fail to do so. The newly identified signature makes it possible to determine which type of infection – e.g. mild or severe, systemic or limited to mucosal membranes – gives rise to sustained immunity. The immune response is also shaped by vaccines, which contain different ingredients and adjuvants. “While everyone responds differently to the virus or a vaccine, cellular immunity plays a crucial role in preventing severe cases of Covid-19 in both vaccinated and recovered people,” says Boyman.