Fig. 2: Anti-SARS-CoV-2 RBD memory B cells from vaccinated monoclonal antibody recipients.

a–c, Flow cytometry enumeration and surface immunoglobulin expression of SARS-CoV-2 RBD-specific memory B cells after vax 1 and vax 2, isolated from monoclonal antibody recipients (green, n = 18) and control individuals^9,11 (blue). n = 26 for vax 1 and n = 31 for vax 2 (a), and n = 10 (b and c). Each dot represents one individual. The red horizontal bars (and the numbers in a) show the median values. a, The number of WT RBD-specific memory B cells per 10 million CD20⁺ B cells (Extended Data Fig. 3a,b). b,c, The percentage of cells among WT RBD-binding CD20⁺ B cells that express cell surface IgG (b) or IgM (c). d, The distribution of antibody sequences derived from cells isolated from five vaccinated monoclonal antibody recipients after vax 2 (Extended Data Fig. 4a–d). The numbers in the inner circles indicate the number of sequences analysed for the respective individual. The green coloured slices indicate clonally expanded cells (same IGHV and IGLV genes, with highly similar CDR3s) within an individual. Slice size is proportional to the number of clonally related sequences, with the fraction of clonally expanded sequences summarized as a percentage (black outline). The white areas of the pie chart indicate the proportion of sequences that were isolated only once. e, The fraction of cells containing IgG (black) versus IgM (white) transcripts per individual (see also Extended Data Fig. 4e and refs. ^9,11). f,g, Somatic hypermutation (SHM) shown as combined heavy- and light-chain variable region nucleotide (nt) substitutions plus one (IGVH + IGVL + 1), with each dot representing one sequence from monoclonal antibody recipients (green) or controls (blue). The ring plots at the bottom show the fraction of sequences with no (IGVH + IGVL + 1 = 1) versus any (IGVH + IGVL + 1 > 1) somatic hypermutation, and the encircled numbers indicate the number of sequences analysed for all cells irrespective of isotype (f), and for IgM and IgG analysed independently (g). The red horizontal bars and numbers in f and g indicate the mean values. Statistical significance was determined using two-tailed Mann–Whitney U-tests (a–c and f), Kruskal–Wallis tests with subsequent Dunn’s correction for multiple comparisons (g) and two-sided Fisher’s exact tests to compare fractions (f and g).