Fig. 2: Neutralizing antibody responses in BALB/c mice after primary series immunization with clinically representative versions of mRNA-1273, mRNA-1273.214 and mRNA-1273.222.
Six-to-eight-week-old female BALB/c mice were immunized twice over a 3-week interval with PBS or 1 μg total dose of clinically representative versions of mRNA-1273, mRNA-1273.214 (1:1 mixture in the vial of separately formulated mRNA-1273 and mRNA-1273.529) or mRNA-1273.222 (1:1 mixture in the vial of separately formulated mRNA-1273 and mRNA-1273.045). Two weeks after (day 35) the second vaccine dose, serum was collected. a, Scheme of immunization and blood draws. b, Neutralizing activity of serum at day 35 against VSV pseudoviruses displaying the spike proteins of Wuhan-1 D614G, BA.1, BA.2.75 or BA.4/5 (n = 16 mice per group, one experiment; tops of boxes show GMTs, which are indicated above each column, and dotted lines show LOD). c, Neutralizing activity of serum at day 35 against pseudotyped lentiviruses displaying the spike proteins of Wuhan-1 DG14G, BA.1 or BA.4/5 (n = 15 for mRNA-1273 and mRNA-1273.214 and n = 16 for mRNA-1273.222, one experiment; tops of boxes shows GMTs, which are indicated above each column, and dotted lines show LOD). Statistical analysis. b,c, One-way Kruskal–Wallis ANOVA with Dunn’s multiple comparison post test; comparisons are between all groups. Exact P values are indicated, and only significant comparisons are shown. Primary data are provided as a Source Data file.
