Fig. 2: Early-life serological profiles and maternal antibody transfer.

a, Longitudinal IgG antibody profiles from mother–infant pairs (n = 94) over the first year of life. Gray triangles represent maternal delivery samples; dots represent infant samples. Red dots denote no observed titer increase between 6 months and subsequent visits; green dots indicate serological evidence of exposure (IgG rise to ≥2 antigens or >0.5 log₁₀ RLU ml⁻¹ to one antigen) between 6 months and subsequent visit. The red line shows the mean with 95% CI (LOESS method). b, Paired maternal and cord blood IgG levels at delivery (n = 94). Box plots show medians, IQR and 1.5× IQR whiskers; outliers are plotted individually. Two-sided paired Wilcoxon signed-rank tests were used, and P values were adjusted using FDR correction. F:MR IgG transfer ratios are shown. c, Antibody dynamics between 6 months and 9–11 months in infants with complete data (n = 86). Each column represents an individual participant. Top panel shows absolute change in log₁₀ IgG levels between 6 months and 9–11 months. Hierarchical clustering using Euclidean distance and complete linkage was performed across individuals (columns) and antigens (rows). Middle panel shows binary changes (blue, increase; white, decrease). Bottom panel highlights infants with serological evidence of exposure. d, Cross-sectional IgG levels by age (n = 413, 0–85 years). Median (black), 80th (blue) and 2.5th/97th centile (red) lines were modeled using fractional polynomials. The bottom panel focuses on children aged 0–15 years. LOESS, locally weighted scatterplot smoothing; P adj., adjusted P value.