Publications Both COVID-19 infection and vaccination induce high-affinity cross-clade responses to SARS-CoV-2 variants Published on August 2nd, 2022 Authors: 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 iScience 2022.19.08.478946; DOI: 10.1016/j.isci.2022.104766 Summary The B.1.1.529 (omicron) variant has rapidly supplanted most other SARS-CoV-2 variants. Using microfluidics-based antibody affinity profiling (MAAP), we have characterized affinity and IgG concentration in the plasma of 39 individuals with multiple trajectories of SARS-CoV-2 infection and/or vaccination. Antibody affinity was similar against the wild-type, delta, and omicron variants (KA ranges: 122 ± 155, 159 ± 148, 211 ± 307 μM-1, 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. Read the publication Instrument: Fluidity One-M Therapeutic area: Covid-19 A full list of recent publications in which our technology has been applied can be accessed here.