Figure 2.

Specificity of the antibody response to chimeric HBcAg and Qβ proteins. BALB/c mice were immunized twice (interval 12 days) with either natural HBcAg (black bars, left panels) or Qβ particles (black bars, right panels), chimeric proteins II-116 (striped bars, left), S2–16 (open bars, left), Qβ 18–25 (striped bars, right), or Qβ Kpn (open bars, right). Primary IgM (d7) and secondary IgG (d19) antibodies were measured on ELISA plates coated with the respective protein used for immunization (A), with natural HBcAg (B, Left) or Qβ (B, Right), or with the peptide preS1 peptide 21–47 (C) containing the immunodominant epitope DPAFR from HBsAg. Titers are indicated as −log₃ of 20-fold prediluted sera. Each bar represents the mean of two to three animals; one of two experiments.