Figure 2. Synergistic enhancement of antibody responses is dependent on the presence of TLRs on B cells.

a) B cell deficient mice (µMT mice) were reconstituted with 40 × 10⁶ B cells from C57BL/6 mice or from MyD88^−/−, TRIF^−/−, TLR4^−/− or TLR7^−/− mice, or equal numbers of TLR4^−/− and TLR7^−/− deficient cells to determine whether expression of TLRs and co-expression of TLR4 and TLR7 on the same B cell was necessary for enhancement of antibody responses. Mice were immunized with 10µg of OVA encapsulated in PLGA nanoparticles and adjuvants. b),c),d) Mice were bled at D28 post primary immunization and OVA-specific total IgG antibody responses were determined using ELISA. Antibody titers are shown (mean + s.e.m of 2 independent experiments, with 3 mice /treatment group in each experiment). *** represents p<0.001 and **p<0.01 (one way ANOVA with Bonferroni post hoc test). e) The magnitude of OVA-specific IFN-γ producing memory CD4+ T cells in the draining lymph nodes of µMT mice is shown with representative FACS plots. f) The magnitude of OVA-specific IFN-γ producing memory CD4+ T cells in the draining lymph nodes is dependent on MyD88 and TRIF expression on B cells. Graphs represent mean frequencies ± s.d of triplicate cultures of pooled lymph node cells from one out of 2 independent experiments.