Fig. 8: Vaccination with Pam2Cys Spike induces potent protection against SARS-CoV-2 challenge.
K18-hACE2 mice (n = 5) were immunized with Pam2Cys alone (P2C; black), or Pam2Cys Spike, sub-cutaneously (s.c; blue) or intra-nasally (i.n; red) three times, two weeks apart. Three weeks post final vaccination mice were challenged with 103 plaque forming units (PFU) of SARS-CoV-2 i.n and protective efficacy assessed. a Anti-Spike IgG and IgA titres (log10 scale) in serum collected one week post final vaccination, determined by ELISA, and b neutralizing antibody (nAb) titres (log10 scale) were determined as the titre needed for 50% inhibition of SARS-CoV-2 infection (ancestral, Beta or Delta variant) in HEK293-ACE2-TMPRSS2 cells. c Mouse weight loss from days 0–7 post infection (p.i) with SARS-CoV-2. d Clinical score distribution, increasing category indicates severity, (no clinical score, blue; category 2, orange; category 3, red) (e) total leukocyte and differential cell counts in the BALF and f lung viral load (PFU) at day 7 p.i. Limits of detection (LOD) indicated by the dotted lines. Data are for individual mice (n = 5 each), means + /− SEM are shown. Statistics: p-values indicated. a, b Mann–Whitney test, (c) Two-way ANOVA with Tukey’s multiple comparisons, (e, f) Kruskal–Wallis test, Dunn’s multiple comparisons. Source data are provided as a Source Data file.
