Fig. 4: HA-nanoparticle immunization elicits enhanced antigen-specific B cell responses that correlate strongly with abundance of TFH.
Total abundance of FAS+ GL7+ germinal center B cells per lymph node was assessed in A BALB/c and B CBA/J mice immunized with equimolar quantities of HA in the form of soluble HA trimers or HA-nanoparticles from the same individual mice shown in Fig. 3. The relationship between germinal center B cell abundance and CD4 TFH abundance was assessed by linear regression analysis for C BALB/c and D CBA/J mice immunized with HA trimers or HA-nanoparticles. When cohorts vaccinated with HA-trimers and HA-Fe-nanoparticles are separately analyzed by linear regression analyses, the same trend is observed. Antigen-specific GC B cell responses were assessed by staining with fluorophore conjugated HA probes, where the B cell population of interest was defined as FAS+ GL7+ IgM- IgD- HA+ for E BALB/c and F CBA/J mice. HA-specific ASCs were assessed by B cell ELISpot. The frequency of HA-specific IgG isotype B cells was assessed for G BALB/c and H CBA/J mice. Data are shown as the mean of three individual mice per group from three independent experiments, for a total of 9 individual mice per group. In (A, B, E, F, G, H), significant differences between HA-trimer and HA-nanoparticle immunized mice were determined by unpaired, two-tailed Mann-Whitney test.
