Figure 4: Vaccination with Abp2D generates antigen-specific memory B cells and bone marrow plasma cells.

a) 6-7 week old C57/Bl6 mice received 3 adjuvanted doses of 50 ug Abp2D_RBD or buffer (mock) and were sacrificed 4 weeks after the 3^rd dose. b) Splenic memory B cells (Live/CD4⁻ CD19⁺/IgD^lo/GL7⁻ CD38⁺/IgG1⁺) were stained with Abp2D_RBD-biotin and detected with SA-APC-Fire750 via flow cytometry. c) Quantification of Abp2D_RBD+ splenic memory B cells as % of IgG1+ memory B cells. d) Total Abp2D_RBD+ memory B cells per spleen. e) Bone marrow was assayed for antigen-specific bone marrow plasma cells via ELISpot. Representative wells from mock-immunized animals and Abp2D_RBD-immunized animals are shown. f) Quantification of Abp2D_RBD-specific bone marrow plasma cells in Abp2D_RBD-immunized animals (n=10). Dotted line indicates the limit of detection (3 cells per 1e6 bone marrow cells). g) Bladder and kidney homogenates and serum from week 4, week 8, and the day of sacrifice were assayed for Abp1D_RBD- and Abp2D_RBD-specific IgG by ELISA. Heatmaps were generated by calculating area under the curve for each serum/tissue sample.