Fig. 1. Adenovirus-based vaccine design and immunogenicity in mice.
a Schematic of SARS-CoV-2 S immunogens. b Western blot of transgene expression from (1) Soriginal, (2) SPtPA add Smature, (3) SPoriginal add Soptimized, (4) SPtPA add Soptimized, and (5) an empty plasmid transfected in HEK293 cells. BALB/c mice (n = 10 per group) received a single immunization with different doses of Ad5-nCoV or Ad5 vector by the IM or IN route. c–h, Humoral immune responses were assessed at weeks 0, 2, 4, 6 and 8 following vaccination by S-specific ELISA c, f, SARS-CoV-2 NAb titration (MN50) d, g and SARS-CoV-2 PNAb titration e, h with n = 10 biologically independent animals per group. Data represent the individual titre of each animal and the connecting lines reflect the geometric means of the titres. i, j, Cellular immune responses were assessed at day 14 following vaccination in the 5 × 108 VP dose groups by intracellular cytokine staining assays with n = 10 biologically independent animals per group. Data are presented as mean ± s.e.m. Statistical significance was determined by Kruskal–Wallis ANOVA with Dunn’s multiple comparisons tests. S = spike protein, SP = signal peptide, tPA = tissue plasminogen activator. Dotted line = the limit of detection. Source data are provided as a Source Data file.