Extended Data Fig. 3: Effect of heterologous vaccine boosting on type-specific serum antibody binding and neutralizing responses.
From: Imprinting of serum neutralizing antibodies by Wuhan-1 mRNA vaccines
Sera were collected 26 days post-vaccination from mice immunized with a single dose of mRNA-1273 (1273) or mRNA-1273.529 (529) (n = 10, two experiments), or 21 days after the last vaccine dose from mice vaccinated with the one prime plus one boost (1273/529, n = 10), two primes plus one boost (1273/1273/529, n = 9), or two primes plus two boosts (1273/1273/529/529, n = 12; also described in Fig. 1) regimens. All vaccines were given at 0.25 μg mRNA per dose. 1273, mRNA-1273; 529, mRNA-1273.529. a, Antibody binding of sera pre-cleared with empty beads (no Dp), BA.1 spike-loaded beads (BA.1 Dp), or Wuhan-1 spike-loaded beads (Wuhan-1 Dp) to Wuhan-1 (left) and BA.1 (right) spike proteins (connecting lines represent sera from the same mouse; LOD for the single dose and the one prime plus one boost cohorts are 1,600 ng/mL equivalents (eq., derived from a mAb standard curve); LOD (dotted lines) for the two primes plus one boost and two primes plus two boosts cohorts are 3,200 ng/mL eq.; values at the LOD are plotted slightly below the LOD for visualization). b, Percentages of Wuhan-1 (left) and BA.1 (right) spike-specific antibodies (horizontal lines and numbers at the top denote median values). Pie charts illustrate the fraction of type-specific and cross-reactive IgG in each group. c, Neutralizing activity of pre-cleared sera against VSV pseudoviruses displaying Wuhan-1 (left) or BA.1 (right) spike proteins (numbers above data points indicate the GMT; fractions indicate the numbers of mice with detectable neutralization by type-specific antibodies; LOD for the single dose and the one prime plus one boost cohorts are 1/25 serum dilution; LOD for the two primes plus one boost and two primes plus two boosts cohorts are 1/50 serum dilution). Pie charts illustrate the fraction of neutralization mediated by type-specific and cross-reactive antibodies in each group. Serum samples with an NT50 below the LOD after pre-clearing with empty beads (no Dp) were not used in pie chart analyses. b, Kruskal-Wallis ANOVA with Dunn’s post-test (P values are shown).