Antibody responses after subcutaneous immunization of HBcAg-wDIII. (A) Scheme of immunization. BALB/C mice were immunized on weeks 0, 3, 6, and 9. Blood samples were collected on the indicated weeks. (B) Antibody responses in sera of immunized mice. Serum wDIII-specific IgG was measured by ELISA. The y-axis shows the geometric mean titers (GMT) and the error bars show the 95% level of confidence of the mean. NS, ***, and **** indicate p values >0.05, <0.001, and <0.0001, respectively, of HBcAg-wDIII VLP-immunized serum compared to that of negative control serum from PBS-injected mice.