COVID-19 Variant Supplement – Towards a comprehensive understanding of adaptive immunity to SARS-CoV-2
The vast majority of people who get COVID19 fully recover from infection. This means that their immune system has successfully eliminated the virus. After we recover from a virus infection, the immune system leaves behind white blood cells, called memory cells, that can remember the previous infection and prevent that infection from recurring upon re-exposure. This is the basis of how vaccines work. After we recover from infection, two kinds of white blood cells persist, T cells and B cells. T cells and B cells have molecules on their surface that allow them to recognize the specific virus they were first exposed to. B cells give rise to antibody producing cells, while T cells can eliminate infected cells. Some antibodies can bind the virus in such a way that they fully block the virus from entering the cell. These are called neutralizing antibodies and these are ideal to fully protect us from being infected again. However, in some infections, weak antibodies, instead of neutralizing the virus, can actually make things worse by promoting uptake of the virus into cells or by overstimulating certain cells of the immune system. Therefore, there is a pressing need to understand the details of the immune response in COVID19 patients. We need to understand what parts of the virus are recognized when we have an immune response associated with a good outcome and what if any aspects of T and B cell responses are associated with a bad outcome. By studying the immune response in asymptomatic, mild and severe cases in depth, we hope to determine the correlates of a good immune response and use this information to design vaccines and to monitor people for the correct immune responses. For some infections T cell and B cell responses last a lifetime, whereas for other infections they do not last as long. Our study will develop the tools we need to follow how long the immune response to COVID19 infection lasts and to help with evaluating the level of protection in the population.