Fig. 3. The immunogenicity of Ad5-S-nb2 in Chinese rhesus macaques.

a Schematic diagram of the vaccination and challenge studies in rhesus macaques. Three groups of macaques (n = 4 per group) were vaccinated via an IM injection of 1 × 10¹⁰ vp or 1 × 10¹¹ vp Ad5-S-nb2 or via an IN and oral inoculation of 5 × 10¹⁰ vp Ad5-S-nb2 each. The control groups include macaques (n = 2) IM injected with 1 × 10¹¹ vp Ad5-empty and non-vaccinated macaques (n = 6). On days 0, 12, 18, and 24 after vaccination, the serum samples and PBMCs were collected. On day 30 (Group 1 and 2) or 56 (Group 3) after vaccination, macaques were challenged. On day 7 or 10 after challenge, macaques were euthanatized. The gray inverted triangles indicate the time points of vaccination or challenge, whereas the gray blood drop symbols indicate the time points at which the serum samples were collected. b The kinetics of IgG response to the S protein in the sera. The endpoint IgG titers are shown. The overlapped data points represent the same values. Comparisons between different time points were performed by Student’s t-test (paired, one-tailed). c The antigen recognition profiles of macaque immune sera. Macaque immune sera collected on day 24 were assessed for the IgG antibodies against the RBD, S2, and S protein by enzyme-linked immunosorbent assay (ELISA). d IFN-γ-secreting cells in the PBMCs of rhesus macaques. PBMCs isolated on day 18 were stimulated with two peptide pools corresponding to S1 and S2, respectively. Shown are the number of SFCs in one million PBMCs. All the data points represent the mean values of two technical replicates. Source data are provided as a Source Data file.