Figure 4.

Neutralizing antibody responses elicited by modified vaccinia Ankara (MVA) prime/boost immunization. Serum samples were obtained at days 0, 14, 28, 42, 56, 84, and 180 following MVA immunization. Serial dilutions were tested for neutralizing activity against a modified vaccinia Ankara recombinant strain containing a luciferase reporter gene (A) or a vaccinia virus recombinant strain containing a luciferase reporter gene (B). Data are presented as median infective dose (ID₅₀) titers with interquartile ranges for each dose group. The limit of detection was a serum ID₅₀ titer of 1:10, and arrows indicate days of immunization. *P ≤ .01 for the 10⁸ median tissue culture infective dose (TCID₅₀) group vs the placebo group; **P ≤ .04 for the 10⁸ TCID₅₀ group vs the 10⁷ TCID₅₀ group.