Fig. 1: Antibody responses in BALB/c mice after a primary immunization series with preclinical versions of monovalent and bivalent mRNA vaccines.
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 preclinical versions of mRNA-1273 (Wuhan-1 spike), mRNA-1273.529 (BA.1 spike), mRNA-1273.045 (BA.4/5 spike), mRNA-1273.214 (benchside 1:1 mixture of mRNA-1273 + mRNA-1273.529) or mRNA-1273.222 (benchside 1:1 mixture of mRNA-1273 + mRNA-1273.045). Immediately before (day 21) or 2 weeks after (day 35) the second vaccine dose, serum was collected. a, Scheme of immunization and blood draws. b, Serum antibody binding to Wuhan-1, BA.1 or BA.4/5 spike proteins by ELISA at day 21 and day 35 (n = 8 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 VSV pseudoviruses displaying the spike proteins of Wuhan-1 D614G, BA.1, BA.2.75 or BA.4/5 (n = 8 mice per group, one experiment; tops of boxes show GMTs, which are indicated above each column and dotted lines show LOD). d, Neutralizing activity of serum at day 35 against pseudotyped lentiviruses displaying the spike proteins of Wuhan-1, BA.1 or BA.4/5 (n = 8 mice per group, one experiment; tops of boxes show GMTs, which are indicated above each column, and dotted lines show LOD). Statistical analysis. b, One-way ANOVA with Tukey’s multiple comparison post test; comparisons are between all groups except for the PBS control, which is shown for reference. c,d, 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.
