Fig 4.
Immunogenicity of Ad-vectored nasal anthrax vaccines in the presence of preexisting anti-Ad5 vector immunity. The A/J mice were first i.n. inoculated with 107 IFU of wt Ad5 per mouse and then after 2 weeks were i.n. immunized with 108 IFU of AdtPA83hu plus 5.4 × 106 IFU of AdmInhAhu (+High), 107 IFU of AdtPA83hu plus 5.4 × 105 IFU of AdmInhAhu (+Median), or 106 IFU of AdtPA83hu plus 5.4 × 104 IFU of AdmInhAhu (+Low). One group of mice without Ad5 priming were immunized with108 IFU of AdtPA83hu plus 5.4 × 106 IFU of AdmInhAhu (−High) as controls. Anti-PA IgG ELISA titers (A) and anti-Letx neutralizing antibody titers (B) were determined at 4 weeks postimmunization. The results of the anti-PA IgG ELISAs and anti-Letx neutralizing assays are plotted as log10 titers. Bars indicate geometric means of the anti-PA ELISA titers or anti-Letx neutralizing antibody titers.