Extended Data Fig. 3: Acetate increases IgA production in E. coli-monocolonized mice and germ-free mice orally administered heat-killed E. coli.

a, Representative flow cytometry plots (gated on DAPI⁺ population) and summary data of caecal SIgA⁺ bacteria in control-diet-fed and WSCA-diet-fed mice monocolonized with B. thetaiotaomicron (n = 9 per group) or E. coli (n = 9 versus 10, respectively). b, Representative flow cytometry plots (gated on lymphocytes) and summary data of colonic IgA⁺B220⁻ plasma cells (PC) and IgA⁺B220⁺ B cells (BC) in mice monocolonized with B. thetaiotaomicron (n = 9 per group) or E. coli (n = 9 versus 10). c, Abundance of E. coli in E. coli-monocolonized mice measured as CFU per gram (CFU/g) of colonic contents (n = 5 per group). d, e, Representative flow cytometry plots (gated on CD3ε⁻ lymphocytes) depicting colonic IgA⁺ plasma cells and B cells in germ-free mice (d) and the absolute number (e) (n = 3 versus 4). f, Faecal SIgA concentration at week 4 in germ-free mice (n = 8 per group). g, Microorganism-reactive SIgA in the caecal contents from control-diet-fed and WSCA-diet-fed germ-free mice orally administered heat-killed B. thetaiotaomicron (n = 4 versus 5, respectively) or E. coli (n = 9 per group). The OD₄₅₀ in the WSCA diet groups was normalized to that of the cWSCA (control) diet groups. h, The frequency among colonic lymphocytes and the absolute number of colonic IgA-producing plasma cells in control-diet-fed and WSCA-diet-fed germ-free mice orally administered heat-killed B. thetaiotaomicron (n = 4 versus 5, respectively) or E. coli (n = 4 per group). i–k, Skewness (i), kurtosis (j) and inverse Simpson’s index (k) of HCDR3 amino acid length distribution in colonic IgA-producing B cells of control-diet-fed and WSCA-diet-fed mice monocolonized with B. thetaiotaomicron (n = 5 per group) or E. coli (n = 4 versus 5, respectively). l, HCDR3 amino acid sequence distribution in control-diet-fed and WSCA-diet-fed mice monocolonized with B. thetaiotaomicron (n = 5 per group) or E. coli (n = 4 versus 5, respectively). Each column corresponds to the sequencing results from a single mouse and the colour corresponds to the order of frequency. m, The frequency of IgA⁺ B cell clones expressing the most-dominant HCDR3 amino acid sequence in control-diet-fed and WSCA-diet-fed mice monocolonized with B. thetaiotaomicron (n = 5 per group) or E. coli (n = 4 versus 5, respectively). n, Mode (that is, the value that appears the most frequently in a sample) of HCDR3 amino acid length in control-diet-fed and WSCA-diet-fed mice monocolonized with B. thetaiotaomicron (n = 5 per group) or E. coli (n = 4 versus 5, respectively). b, c, e, f, Data are mean and s.d. a, g–k, m, n, Box plots indicate median, upper and lower quartiles, and upper and lower extremes except for outliers. *P < 0.05, **P < 0.01; two-sided Wilcoxon rank-sum test (a–c, e–g, i–k, m, n) and Kruskal–Wallis test with Dunn’s test (h). a, b, f, g, Pooled data from two independent experiments. Exact P values are provided in the Source Data.

Source data