Following several studies over the past year that observed T cells gathered before the pandemic show reactivity against both the spike and nucleocapsid proteins of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) and several non-structural proteins. Most of the T cell’s response was detected against spike proteins similar to those seen in coronaviruses known to cause the common cold. It is hypothesized that T cell immunity is likely to have originated from exposure to these viruses. A group of researchers from the University Of Cologne investigated a similar phenomenon in B cells in a study available on the preprint server bioRxiv*.
