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. Author manuscript; available in PMC: 2018 Nov 18.
Published in final edited form as: Science. 2018 May 3;360(6390):795–800. doi: 10.1126/science.aaq0926

Fig. 3. B. fragilis induces a specific IgA response, dependent on ccf regulation of surface capsular polysaccharides, which enhances epithelial adherence.

Fig. 3

(A) RNAseq gene expression analysis of RNA recovered from whole ascending colon tissue of mice mono-colonized with B. fragilis or B. fragilis Δccf (n = 3). (B) Flow cytometry plots and (C) quantification of IgA coating of B. fragilis from feces of mice mono-colonized with various strains (Tukey ANOVA, n = 11–12). (D) ELISA for total fecal IgA in mono-colonized mice (Sidak repeated measure 2-way ANOVA, not significant, n = 4). (E) Bacterial lysates from feces of mono-colonized Rag1−/− mice probed in Western blots with fecal IgA from B. fragilis mono-colonized mice and (F) quantification of the proportional signal from IgA binding to capsular polysaccharides (CPS) (over 245 kDa) (Tukey ANOVA, n = 3 mice). (G) Binding of fecal IgA extracted from mono-colonized mice to various strains of B. fragilis. Source of IgA is mice colonized with either WT B. fragilis or B. fragilis Δccf. Because ccf is expressed in vivo, IgA-free bacteria from feces of mono-colonized Rag1−/− mice were used as the target for IgA binding (Tukey 2-way ANOVA, *significantly different from WT bacteria with WT IgA, n = 3). (H) In vitro epithelial cell adherence assay using IgA extracted from Swiss Webster mice (or Rag1−/−, second column) mono-colonized with B. fragilis or B. thetaiotaomicron (theta; last column). IgA-free but in vivo-adapted bacteria were isolated from mono-colonized Rag1−/− mice (Tukey ANOVA, n = 4 mice as the source of bacteria) (* p < 0.05, ** p < 0.01, *** p < 0.001).