Fig. 5. Induction of efficient humoral and cellular immunity in non-human primates by COReNAPCIN^®.

a Rhesus macaques (n = 2 each group) were immunized with either 30 µg (pink) or 50 µg (purple) COReNAPCIN^® at days 0 and 28 and were challenged with 2 × 10⁸ PFU of SARS-CoV-2, 21 days after the boost injection. Animals in the control group were administrated with PBS (gray). b–f Serum samples were subjected for evaluating the COReNAPCIN^® induced humoral immune responses. The black arrows under the x-axis represent vaccination days while the red one denotes the challenge day. The titer of anti-Spike (b) and anti-RBD (d) specific IgG binding antibody in sera before prime and eight indicated time points post prime were determined by ELISA. The neutralizing capacity were assessed in the sera of day 14 post boost by cVNT (c), and in the sera of indicated different time points by sVNT (d) and pVNT (f). g–i PBMCs isolated 21 days post-boost injection, were subjected for assessing the COReNAPCIN^® induced cellular immune response. Using an ELISpot assay (g, h), after 24 h stimulation with SARS-CoV-2 peptide pool (S1 and S2), the frequency of IFN-γ producing cells per 10⁶ splenocytes were quantified (h). In (g), the representative images of ELISpot wells, columns from left to right are: responses of PBMCs to S1 and S2 SARS-CoV-2 peptide pool (as duplicate), DMSO (a negative control), and Anti CD3 (an unspecific positive control). Each row represents an individual rhesus macaque. An ELISA assay (i) was used to assess the IFN-γ (square shape symbol, □) and IL-4 (circle shape symbol, ●) cytokine level in the cell culture supernatants following 8 h stimulation with SARS-CoV-2 peptide pool. In bar plots, each data point is shown and the height of each bar represents the mean.