FIGURE 2.

Induction of antigen-specific IgG in nanoparticle vaccinated mice. ELISA was performed in triplicate using coated peptide pool. Serum IgGs (1:20,000 dilution) in differentially immunized mice were compared. Mock: PBS injection only; NP: empty nanoparticle infection; rTcdB: injection with 20 μg purified rTcdB in PBS. NP₂₀₀, NP₃₅₀, NP₅₀₀, and NP₇₅₀: injection with NP-rTcdBs with the corresponding size in nanometers; Al+rTcdB: injection with 20 μg purified rTcdB mixed with Alum. All data are presented as mean ± standard deviations and statistical comparisons among groups were analyzed by Student’s t-test and ANOVA (^∗∗p ≤ 0.01, ^∗∗∗p ≤ 0.001, ^∗∗∗∗p ≤ 0.0001). NS, not significant. All data are representative of at least three independent experiments.