Fig. 6: Immunogenicity of CDO-7N-1 in cynomolgus macaques post-intranasal immunization.

Cynomolgus macaques were immunized with 10⁵ PFU CDO-7N-1 intranasally in a volume of 250 µL in each nostril (n = 10). a–d Viral RNA in the nasopharyngeal fluid (a), tracheal fluid (b), BALF (c) and rectal fluid (d) was assessed using RT‒qPCR at days 0, 3, 4, 5, 8, 11, 16 and 32 post-immunization. Dotted horizontal lines indicate the detection limit. e Histopathological changes in the lungs of unimmunized and immunized macaques. Macaques were sacrificed at two days post-immunization. The nasal mucosa, lung and masseter muscle were collected for H&E staining. Scale bar in panel = 50 µm. The images provided are representative of two macaques from the vaccine group and one macaque from the PBS group. f, g Serum samples were collected for ELISA targeting anti-spike and RBD protein IgG at 0, 2, 4 and 6 weeks post-immunization. The data in WHO International Standard (BAU/mL) is included in supplementary information (Supplementary Fig. 16a, b). h Plasma samples were collected at indicated time points for Spike specific neutralizing IgG assay. Dotted horizontal lines indicate the detection limit. Data in µg/mL for monoclonal antibody to SARS-CoV-2 Spike protein is in Supplementary Fig. 16c. i, j Nasopharyngeal fluid was collected for ELISA targeting anti-spike and RBD protein IgA at 0, 7, 15 and 31 days post-immunization. k–m At 0, 7, 15 and 31 days post-immunization, PBMCs were collected and stimulated with spike (k, l) protein and N protein (m) peptide pool (2 μg/mL). IFN-γ producing T cells specific for Spike protein and N protein were quantified with an Automated ELISpot Reader ELR08IFL. Data are presented for individual animals.