(A) Schematic of dosing schemes. (B-H) C57BL/6J mice (n=9 animals/group) were immunized with 10 μg N332-GT2 trimer and 5 μg SMNP adjuvant according to the dosing schemes in (A). GC responses were evaluated on days 7, 14, 21, and 28 by flow cytometry and antibody responses by ELISA on days 3, 7, 14, 21, and 28. Shown are trimer-specific B cell counts (B), GC B cell counts (C), Tfh cell counts (D), trimer-specific GC B cell counts (E), plasmablast counts (F), trimer-specific IgM titers (G), and trimer-specifc IgG titers (H), plotted over time for bolus and 2-ED regimens. Shown are data from one independent experiment for each immunization series. ****, p < 0.0001; ***, p < 0.001; **, p < 0.01; *, p < 0.05; ns, not significant; by two-way ANOVA with Dunnett’s multiple comparison post test compared to bolus immunization.