Fig. 7: Cell-mediated immune responses and virus-neutralization (VN) titers in mice immunized by a prime-boost approach using BAd and HAd vector formulations.
Seven-week-old BALB/c mice (3 males + 3 females per group) were intranasally (i.n.) mock-inoculated or inoculated with BAd vector individually or various combinations as shown in Fig. 5C with a dose of 1 × 107 plaque-forming units (PFU) (each vector). At four weeks post-prime, each group received a booster i.n. inoculation with HAd vector individually or various combinations as shown in Fig. 5C with a dose of 1 × 107 PFU (each vector). Four weeks post-booster inoculation, splenocytes (A–C), mediastinal lymph nodes (MLN) (D–F), and lung mononuclear (MN) cells (G–I) were collected and analyzed for S- (A, D, G), N- (B, E, H), or M-specific (C, F, I) T-cell-mediated immune responses by ELISpot assay using antigen-specific peptides. Numbers of IFN-γ-secreting cells per 106 splenocytes (A–C), 106 MLN cells (D–F), or 105 lung MN cells (G–I) are presented. *, significant at p < 0.05; and **, significant at p < 0.01. VN titers against SARS-CoV-2 variants in sera of mice immunized by a prime-boost approach using BAd and HAd vector formulations. Four weeks post-booster inoculation, the serum samples were collected and used to study the development of VN titers against SARS-CoV-2 variants: J hCoV-19/USA/PHC658/2021 (B.1.617.2, Delta) and K hCoV-19/USA/GR484A/2021 (B.1.1.529, Omicron) by VN assay.
