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Our newest data showed antibody and memory B cell responses in a cohort of 20 volunteers who received either the Moderna (mRNA-1273) or Pfizer/BioNTech (BNT162b2) vaccines. 1/ https://www.biorxiv.org/content/10.1101/2021.01.15.426911v1
mRNA vaccines elicit antibody responses in a way that resembles natural infection; however, plasma neutralizing activity from vaccinee was modestly but significantly reduced by SARS-CoV-2 variants encoding E484K, N501Y or a combination of K417N/E484K/N501Y. 2/
Neutralization potency from vaccinee plasma is similar to that from natural infection; and neutralizing activities were directly correlated to the time between the first vaccine dose and blood donation. 3/
Responses to Spike and RBD were significantly higher compared to pre-COVID-19 historic controls, anti-S and -RBD IgG levels were higher than IgM or IgA. While there was greater variability in the anti-RBD than the anti-S response, the two were positively correlated. 4/
Plasma neutralization potency elicited by mRNA vaccines is less effective against newly circulating variants that carry certain RBD mutations (N501Y, E484K, KEN). 5/
The relative numbers of RBD-specific memory B cells were equivalent to individuals who recovered from natural infection. 6/
Antibodies that share the same combination of IGHV and IGLV genes in vaccinees comprised 39% of all the clonal sequences and 59% when combined with naturally infected individuals. 7/
Nearly identical antibodies were found in different individuals immunized with either the Moderna (mRNA-1273) or Pfizer-BioNTech (BNT162b2) vaccines. 8/
IC50 of mRNA vaccine-elicited antibodies is similar to that from natural infection. 9/
As seen in natural infection, a majority of the antibodies tested (9/17) were at least ten-fold less effective against pseudotyped viruses carrying the E484K, 5 of the antibodies were less potent against K417N and 4 against N501Y by ten-fold or more. 10/
Notably, 6 of the antibodies selected for K417N/E/T, 5 selected for E484K and 3 selected for N501Y/T/H, which coincide with mutations present in the circulating B1.1.17, 501Y.V2 and B1.1.28/501.V3 variants. 11/
