Fig. 1. Antibody responses in the serum of K18-hACE2 mice after ChAd-vectored vaccine immunization.
a, Diagram of the ChAd-SARS-CoV-2-BA.5-S vaccine encoding the Omicron BA.5 S protein with the indicated furin cleavage site and six proline substitutions, with substitutions in the BA.5 S protein shown in red; the positions of the residues correspond to the ancestral SARS-CoV-2 Wuhan-1 S protein; ITR, inverted terminal repeats; CMV, cytomegalovirus. b, Scheme of immunizations, blood collection and virus challenge. c–p, Cohorts of 7- to 9-week-old female K18-hACE2 mice were immunized i.n. with ChAd-Control, ChAd-SARS-CoV-2-S, ChAd-SARS-CoV-2-BA.5-S or bivalent ChAd vaccine. Sera were collected 4 weeks after immunization, and serum RBD-specific IgG (c–f) and IgA (g–j) levels (n = 10, two experiments) and neutralizing antibody titers (k–p; n = 5, 10, 10, 10 and 10 (left to right), two experiments) against the indicated authentic SARS-CoV-2 strains were determined. Boxes illustrate geometric mean values, and dotted lines show the LOD. Data were analyzed by one-way analysis of variance (ANOVA) with a Tukey’s post hoc test (c–j) or Dunnett’s post hoc test (k–p); *P < 0.05, **P < 0.01 and ****P < 0.0001; IC50, half-maximal inhibitory concentration; NS, not significant.