Both COVID-19 infection and vaccination induce high-affinity cross-clade responses to SARS-CoV-2 variants
Marc Emmenegger, Sebastian Fiedler, Silvio D. Brugger, Sean R. A. Devenish, Alexey S. Morgunov, Alison Ilsley, Francesco Ricci, Anisa Y. Malik, Thomas Scheier, Leyla Batkitar, Lidia Madrigal, Marco Rossi, Georg Meisl, Andrew K. Lynn, Lanja Saleh, Arnold von Eckardstein, Tuomas P. J. Knowles, Adriano Aguzzi
Abstract
, respectively), indicating a surprisingly broad and mature cross-clade immune response. Postinfectious and vaccinated subjects showed different IgG profiles, with IgG3 (p-value = 0.002) against spike being more prominent in the former group. Lastly, we found that the ELISA titers correlated linearly with measured concentrations (R = 0.72) but not with affinity (R = 0.29). These findings suggest that the wild-type and delta spike induce a polyclonal immune response capable of binding the omicron spike with similar affinity. Changes in titers were primarily driven by antibody concentration, suggesting that B-cell expansion, rather than affinity maturation, dominated the response after infection or vaccination.