Fig. 2: Memory B cell antibodies.

a, Representative flow cytometry plots showing dual AlexaFluor 647–RBD- and PE–RBD-binding B cells for four vaccinated individuals. b, As in a, dot plot summarizes the percentage of RBD-binding B cells in 19 vaccinated individuals, in comparison to a cohort of naturally infected individuals assayed at 1.3 and 6.2 months after infection^5,6. Individuals who received the Moderna vaccine are shown in black and individuals who received the Pfizer–BioNTech vaccine are in red. Red horizontal bars indicate mean values. Statistical significance was determined using two-tailed Mann–Whitney U tests. c, Pie charts show the distribution of antibody sequences from the four individuals in a. The number in the inner circle indicates the number of sequences analysed. Pie-slice size is proportional to the number of clonally related sequences. The black outline indicates the frequency of clonally expanded sequences. d, As in c, graph shows relative clonality among 14 vaccinated individuals. Individuals who received the Moderna vaccine are shown in black and individuals who received the Pfizer–BioNTech vaccine are in red. Red horizontal bars indicate mean values. Statistical significance was determined using two-tailed Mann–Whitney U tests. e, Graph shows relative abundance of human IGVH genes in data from Sequence Read Archive accession SRP010970 (database) (orange), and vaccinated individuals (blue). A two-sided binomial test was used to compare the frequency distributions. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. f, Clonal relationships between sequences from 14 vaccinated individuals (Moderna in black, Pfizer–BioNTech in red) (Supplementary Table 3) and naturally infected individuals^5,6 (green). Interconnecting lines indicate the relationship between antibodies that share V and J gene-segment sequences at both IGH and IGL. Purple, green, and grey lines connect related clones, clones and singles, and singles to each other, respectively. g, Number of somatic nucleotide mutations in the IGVH (top) and IGVL (bottom) in antibodies from vaccinated individuals (Supplementary Table 3), compared to those from naturally infected individuals obtained at 1.3 or 6.2 months after infection^5,6. Statistical significance was determined using two-tailed Mann–Whitney U tests. Red horizontal bars indicate mean values. h, As in g, but for CDR3 length in amino acids (aa).