Fig. 2

Nucleoside-modified HA mRNA-LNP immunization elicits HA stalk-specific antibody responses in mice. Mice received two i.d. (3, 10, or 30 µg) (a, b) or i.m. (10, 30, or 90 µg) (c, d) immunizations of A/California/07/2009 HA mRNA-LNPs or 30 (i.d.) or 90 (i.m.) µg of poly(C) RNA-LNPs at weeks 0 and 4. IgG binding to full-length H1 HA (a, c) and cH6/1 HA (b, d) proteins was determined at week 4 and week 8. n = 3–10 mice. Two independent experiments were performed. Error bars are SEM. Statistical analysis: a, b two-way ANOVA with Bonferroni correction, *p < 0.05 comparing A/California/07/2009 HA mRNA-LNP dose groups at each serum dilution, black star: significant difference in titers between the 3 and 30 µg groups, purple star: significant difference in titers between the 3 and 10 µg groups, green star: significant difference in titers between the 10 and 30 µg groups; c, d two-way ANOVA with Bonferroni correction, *p < 0.05 comparing A/California/07/2009 HA mRNA-LNP dose groups at each serum dilution, blue star: significant difference in titers between the 10 and 90 µg groups, green star: significant difference in titers between the 10 and 30 µg groups, gray star: significant difference in titers between the 30 and 90 µg groups