Fig. 1: Immunity to coronavirus spike glycoprotein in the young and old.
From: Boosted immunity to the common cold might protect children from COVID-19
The sequence conservation of the spike glycoprotein among alphacoronaviruses and betacoronaviruses is limited in the receptor-binding domain and N-terminal domain of the S1 subunit of the viral spike protein. However, the SARS-CoV-2 S2 subunit is highly conserved with commonly circulating endemic coronaviruses. As a result, S2-specific immune responses to SARS-CoV-2 are often cross-reactive across the betacoronavirus clade, indicating that some individuals, particularly children who have high levels of immunity to these common viruses, have a pre-existing head start in immunity to SARS-CoV-2 and produce a more robust cross-reactive antibody and T cell response. TCR, T cell antigen receptor.
