FIG. 4.

Anti-E antibodies in recipient animals to which was transferred immune serum (A) or splenocytes (B). C3H/HeN mice that were immunized with pE or pcDNA3 three times at 3-week intervals or sublethally immunized twice at 3-week intervals with live JEV Beijing-1 were used as donor animals. Immune splenocytes and sera were prepared as described in Materials and Methods. Naïve animals that were sublethally irradiated 24 h before were inoculated intravenously with 300 μl of sera or 5 × 10⁷ splenocytes and challenged with 50 LD₅₀ of JEV Beijing-1 12 h after transfer. Serum samples were collected 4 h, 4 days, or 14 days after transfer and analyzed for the presence of E-specific antibodies. i.m., intramuscular.