Hypothesis
T cells reacting to SARS-CoV-2 spike protein in people never exposed to the virus would be explained by near-identical epitopes shared with common human pathogens, especially endemic coronaviruses.
What failed
Epitope prediction combined with similarity searches against common human pathogens found that the SARS-CoV-2 epitopes most similar to beta-coronavirus ones sit in replication-associated proteins, not in the host-interacting spike protein.
Broken assumption
Cross-reactive T cell memory to a new virus comes from near-identical epitopes in related pathogens.
Why
On this computational evidence the authors conclude near-identical epitopes do not drive the observed pre-formed immunity to structural proteins; what does is left open.
From the published paper: Stervbo et al. Scientific Reports, 2020. ↗CC BY