Fig. 6
Cross-reactivity of the systemic immune response generated in Balb/C mice by the intranasal administration of CND-1 alone and combined with ODN-39 M. Thirty days after the third immunization mice were sacrificed. a IgG antibody response against N protein from SARS-CoV-1, MERS-CoV, and SARS-CoV-2 Omicron variant were measured by ELISA in sera at 1:100 dilution. Data are expressed as O.D values, horizontal bar represents the mean value. b Cell-mediated immune response. Spleens cells were isolated and in vitro stimulated with the conserved peptide N351–365 and N proteins from SARS-CoV-2, Delta and Omicron variants, and SARS-CoV-1. The frequency IFN-γ secreting cells was measured by ELISpot. Square dots represent a pool of placebo samples. The horizontal bar represents the mean value for each group (n = 5)