Fig. 2: RepHA-Bovine is immunogenic and protective against lethal A/bovine challenge in mice.

a Mice (n = 4 per group) were immunized with indicated repRNAs and HA-binding antibodies measured against indicated recombinant HAs (a) or NP (b). c Viral neutralization (VN) titers of pooled sera (n = 4 per group) were measured against infectious A/Vietnam or A/bovine virus and data shown as technical replicates. Splenocytes were evaluated for HA-specific T cells by IFNγ ELISpot. d Splenocytes were stimulated with overlapping peptides spanning the A/Vietnam HA in five pools and data shown as the cumulative spot count from all five peptide pools. e, f Mice (n = 6 per group) were challenged with 100,000 TCID₅₀ of A/bovine via the intranasal route and weighed daily (d) and euthanized when they reached >20% weight loss or exhibited signs such as severe lethargy or neurological signs. Box plots indicate mean plus standard deviation. a, b P values calculated with an ordinary one-way ANOVA with Tukey’s multiple comparisons test. d P values calculated with an ordinary one-way ANOVA with Dunnett’s multiple comparisons test to sham-vaccinated mice. e P values calculated with log-rank test with Bonferroni correction for multiple comparisons. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.