a, Representative plots of intracellular S staining in CD20loCD38+IgDloCD19+/loCD3− live singlet BMPCs (gating in Extended Data Fig. 1a) from magnetically enriched BMPCs from control individuals (left) or convalescent individuals 7 months after symptom onset (right). b, Frequencies of S-binding BMPCs in total BMPCs from control individuals (black circles) or convalescent individuals 7 months after symptom onset (white circles). Horizontal lines indicate the median. P value from two-sided Mann–Whitney U test. Each symbol represents one sample (n = 12 convalescent, n = 9 control). c, Histograms of BLIMP-1 (left), Ki-67 (centre), and CD38 (right) staining in S+ (blue) and HA+ (black) BMPCs from magnetically enriched BMPCs 7 months after symptom onset, and in S+ plasmablasts (red) and naive B cells (grey) from healthy donor PBMCs 1 week after SARS-CoV-2 S immunization.