Figure S5.

Identification of SARS-CoV-2-binding MBCs. Related to Figure 6

(A) Flow cytometry gating strategy for identification of spike and RBD-binding MBCs.

(B) Frequency of RBD MBCs gated from spike MBCs. p values on the top show the differences between each time point in the different vaccines. The bottom bars show T4 to T5 statistics.

(C) Representative gating strategy of Ig isotypes gated on RBD-binding MBCs. Colors reflect the Ig isotype distribution displayed in the donut graphs in Figure 6D.

(D) Overlay of Ig isotypes from RBD MBCs onto CD27 and IgD flow cytometry plots. The “other” RBD MBCs were predominantly IgD^neg and CD27⁺, similarly to the IgG⁺ RBD MBCs. Since most of the RBD MBCs were IgG⁺, the phenotypic similarity of the “other” RBD MBCs suggests they may be IgG isotype MBCs that did not sufficiently bind to the anti-IgG reagent.

Data were analyzed for statistical significance using the Mann-Whitney test [(B)].