FIG. 4.
Transgene product-specific antibody response upon homologous or heterologous primer-booster immunization with Ad recombinants. (A) Groups of five ICR mice were vaccinated per os with 2 × 106 PFU of AdHu5rab.gp or AdC68rab.gp. Mice were bled 2 weeks later. Mice were given booster immunizations 4 weeks after vaccination with 2 × 106 PFU of the homologous virus (closed symbols), i.e., AdHu5rab.gp-immune mice were given AdHu5rab.gp and AdC68rab.gp-immune mice were given AdC68rab.gp, or the heterologous virus (half-closed symbols), i.e., AdHu5rab.gp-immune mice were given AdC68rab.gp and AdC68rab.gp-immune mice were given AdHu5rab.gp. Sera were tested 2 weeks and 3 months after the booster immunizations in parallel with sera harvested after the first immunization (open symbols) and normal mouse serum controls (X). 1std, first dose. (B) The same set of mice whose results are shown in Fig. 1A were tested 2 weeks after priming (−2) and 2 and 12 weeks after booster immunization for VNAs to rabies virus. Solid bars, homologous primer-booster immunization; striped bars, heterologous primer-booster immunization. (C) Groups of five ICR mice were vaccinated i.m. with 105 PFU of AdC68 and then received booster immunizations i.m. with either 105 PFU of the same vector or 105 PFU of the AdHu5rab.gp vector. One group did not receive booster immunizations. Mice were bled 4 weeks later, and titers of VNAs to rabies virus were determined by comparison of sera from vaccinated ICR mice to sera from unvaccinated ICR mice (control). Data are expressed in international units, determined by comparison with a World Health Organization reference serum. (D) Vaginal lavage fluids from mice immunized per os with 2 × 106 PFU of AdHu5rab.gp (left panels) or AdC68rab.gp (right panels) and then given booster immunizations with the same dose of the homologous or heterologous construct 4 weeks later as described for panel A were tested for the isotype profile of antibodies to rabies virus. The upper panels show the profiles 2 weeks after priming with AdHu5rab.gp (solid bars) or AdC68rab.gp (striped bars), the middle panels show the isotype profiles 2 weeks after booster immunization, and the lower panels show isotypes 6 weeks thereafter. Levels of vaginal lavage fluid antibodies from control mice are shown with speckled bars. (E) Groups of mice were vaccinated per os with 2 × 107 PFU of AdHu5rab.gp (closed bars) or AdC68rab.gp (open bars). They received booster immunizations 4 weeks later with the same dose of the homologous construct given orally. Antibody titers in vaginal lavage fluids and antibody isotypes were tested 2 months later. Speckled bars, control vaginal lavage fluid. (F) The graph summarizes data from Fig. 4B and C, showing the ratio of IgA antibodies to IgG2a antibodies to rabies virus in vaginal lavage fluids of mice that had been immunized twice orally with the recombinant vaccines. (G) Fecal suspensions of mice immunized 4 weeks earlier with 2 × 107 (solid bars) or 2 × 106 (striped bars) PFU of AdHu5rab.gp virus were tested for isotypes of antibodies to Ad in comparison to control samples (speckled bars).