Figure 2.

Analyses of plasma response to SARS-CoV-2 and the RBD-specific memory B cells. (A) The heatmap depicts the specificity of convalescent patients’ plasma against S1 or RBD of SARS-CoV-2, SARS-CoV, and MERS-CoV, with serial dilutions, measured by ELISA. The plasma of healthy donors was used as a negative control. All results were derived from at least two independent experiments. (B) Gating strategy for SARS-CoV-2 RBD-specific IgG⁺ mB cells in the PBMC of COVID-19 convalescent patients. Living CD19⁺IgD^-IgG⁺ cells were gated, and B cells binding SARS-CoV-2 RBD were selected for single-cell sorting. (C) FACS analysis of RBD-specific memory B cells in CD19⁺IgD^-IgG⁺ mB cells from the PBMC of three batches of convalescent patient samples. Plots show CD19⁺IgD^-IgG⁺ populations using the gating strategy described in (B).