Extended Data Fig. 7: Natural anti-E. coli maternal antibodies override neonatal infection susceptibility.

a, Survival and bacterial burden one day after infection for 8-week (adult) (n = 6) compared with 3-day (neonate) (n = 7) old mice intraperitoneally (IP) infected with 200 CFUs E. coli UTI89. b, Survival and bacterial burden one day after UTI89 infection (200 CFUs, administered IP) in 3-day old pups born to control mice without EcN colonization (n = 9) compared with EcN colonized WT (n = 10) or EcN colonized μMT-/- (n = 7) dams. c, Survival and bacterial burden one day after UTI89 infection (5 × 10⁶ CFUs, oral gavage) in 3-day old pups born to control mice without EcN colonization (n = 10) compared with EcN colonized WT (n = 9) dams. d, Anti-EcN IgG or IgM titers in EcN colonized dams and their 3-day old pups (n = 5; lines indicate each paired maternal:pooled pup specimens). e, Bacterial burden one day after UTI89 infection (200 CFUs, administered IP) in 3-day old pups administered each dosage of purified IgG from EcN colonized or control mice without E. coli colonization one hour prior to infection (n = 3–5 mice/group, with each dot representing the data from an individual animal). f, Nucleotide differences between two parental EcN stocks, compared with strains isolated from the feces of EcN colonized virgin or postpartum mice. g, Bacterial burden one day after UTI89 infection (200 CFUs, administered IP) (left) or compared with anti-EcN IgG titers (right) for pups born to EcN colonized dams (n = 10), pups born to control mice without EcN colonization (n = 9) or cross-fostered within the first 12 h after birth (n = 8 [prenatal]; n = 9 [postnatal]). Data are presented as mean values (bar) ± one standard deviation. Differences between groups analysed using unpaired Student’s t test (panels a, c), one-way ANOVA (panels b, g [left]), paired Student’s t test (panel d), using Log-rank (Mantel-Cox) test (panels a - c), or simple linear regression (panel g [right]). LOD, limits of detection.

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