Extended Data Fig. 1: Isolation of B cell populations for sequencing studies.

Extended Data Figure 1a, gating strategy used for the isolation of naïve B cells (NB), memory B cells (MB), plasmablasts (PC), germinal center centroblasts (CB), and germinal center centrocytes (CC) from human tonsillar lymphocytes using multiparameter fluorescence activated cell sorting (FACS). Lymphocytes were isolated from fresh human tonsils by density gradient centrifugation. Within 24 hours, cells were either sorted by FACS or cryopreserved for cell sorting on a later date (see Methods). Prior to sorting, lymphocytes were labeled with anti-CD20, anti-CD10, anti-CD44, anti-CD27, anti-CD38, and anti-CXCR4 conjugated flourochromes. DAPI was used to exclude non-viable cells. For isolation of NBs, centroblasts, and centrocytes only, anti-IgD was used in place of anti-CD38 and anti-CD27, and NBs were CD20⁺CD44⁺CD10⁻IgD⁺. Details of antibodies used for cell sorting are listed in Extended data Table 1. SSC: side scatter, FSC: forward scatter.