Fig. 2.

Induction of SARS-CoV-2-specific IgG by AdCoV2 vaccines. Five mice per group of BALB/c were immunized with 1 × 10⁷ pfu Ad-LacZ, AdCoV2-S, or AdCoV2-SdTM via i.n. or AdCoV2-S via s.c., five mice per group at 14-day intervals. The varying dilutions of sera collected at 14 days (A) or 1 (B), 2 (C), or 3 (D) months post boost were analyzed using IgG anti-recombinant intact S protein-immobilized ELISA. Anti-mouse IgG conjugated with HRP was used as the detection antibody. The titer of specific antibody in the serum was calculated as a fold dilution of the tested sera, whose detected value at OD450 nm of absorbance > 3 times the value at OD450 nm of absorbance obtained from the medium alone.