Capsid-incorporated antigens elicit an IgG immune response. C57BL/6J mice were immunized with 1010VP of Ad vectors. Post-immunization sera were collected after (A) 30 days post-injection or (B) 0–70 days post-injection for ELISA binding assays. 20 μM of synthesized antigenic peptide His6 peptide was bound to ELISA plates. Residual unbound peptide was washed from the plates. The plates were then incubated with immunized mice sera, the binding was detected with IgG-specific HRP-conjugated anti-mouse secondary antibody. OD absorbance represents the sera levels of antibodies. Values are expressed as the mean ± standard error of three replicates. * indicates a P value of <.05., ** P < .001, *** P < .00001. Control viruses are Ad5, Ad/HVR2-His6 and Ad/HVR5-His6.