Fig. 1.

CMI against Ad5 [E1-]-CEA and Ad5 [E1-, E2b]-CEA in Ad5 immune mice. C57Bl/6 mice (n = 5 per group) were pre-immunized two times at a 2-week interval with 10¹⁰ VP Ad5-null (containing no transgene) to induce Ad5 immunity. Separate groups were then immunized three times at 1-week intervals with 10¹⁰ VP Ad5 [E1-]-CEA or Ad5 [E1-, E2b-]-CEA. Controls received injection buffer alone. Splenocytes were collected 14 days after the final immunization and assessed for IFN-γ secreting cells (a) or IL-2 (b) by ELISpot assay. Splenocytes were also assessed for non-specific secreting cells of IFN-γ (a) or IL-2 (b) following stimulation with the non-immunizing antigens β-galactosidase (β-gal) and HIV-1 Gag. For positive controls, splenocytes were exposed to Concanavalin A (Con A) (data not shown). Data are reported as the number of spot forming cells (SPF) per 10⁶ splenocytes. The error bars depict the SEM