FIG. 3.

Immunogenicity of MRKAd5-NSmut and MRKAd6-NSmut in naïve and in Ad5 preimmune mice. (A) Immunogenicity of MRKAd5-NSmut and MRKAd6-NSmut in naïve mice. IFN-γ ELISPOT responses to the NS3h peptide pool and the CD8⁺ peptide G-1480 in C57BL/6 mice immunized with MRKAd5-NSmut and MRKAd6-NSmut at doses of 10⁷ and 10⁹ VP (indicated at the bottom). Results are expressed as the number of IFN-γ SFC per 10⁶ splenocytes and are reported on the vertical axis. Each bar represents the average of the response to the NS3h peptide pool (gray bars) and CD8⁺ G-1480 peptide (black bars) measured in groups of 10 immunized mice. Response to DMSO is represented by the white bars. Average number of spots in DMSO control samples was 2 per 10⁶ splenocytes. (B and C) Immunogenicity of MRKAd5-NSmut and MRKAd6-NSmut in mice with preexisting anti-Ad5 immunity. C57BL/6 mice were preimmunized with 10¹⁰ VP of Ad5 expressing an unrelated antigen. Groups (n = 5) of naive mice or mice with anti-Ad5 immunity were immunized with 10⁸ VP of MRKAd5-NSmut or MRKAd6-NSmut, and responses against NS3h peptide pool were assessed by IFN-γ ELISPOT assay. Results are expressed as the number of IFN-γ SFC per 10⁶ splenocytes and are reported on the vertical axis. Each bar represents the individual response of animals immunized with MRKAd5-NSmut (B) or MRKAd6-NSmut (C). Anti-Ad5 neutralization titers were between 200 and 4,000 except in mouse m10 (NAb of 50).