CMI dose response titration of Ad5 [E1-, E2b-]-HA and Ad5 [E1-, E2b-]-NA. Ad5 naïve BALB/c mice (n = 5/group) were immunized three times every two weeks using a dose of 108, 109 or 1010 VP Ad5 [E1-, E2b-]-HA (a), Ad5 [E1-, E2b-]-NA (b) or Ad5 [E1-, E2b-]-HA + NA (c and d) or buffer alone (controls). Fourteen days after the final immunization, splenocytes from the mice were assessed by ELISpot analysis for IFN-γ (black bars) or IL-2 (striped bars) secretion following antigen peptide stimulation. The greatest induction of CMI was achieved using 1010 VP of the vector. For positive controls, splenocytes were pulsed with concanavalin A in all ELISpot assays (data not shown). The error bars depict the standard error of the mean (SEM).