(A) B6 mice were treated for 2 weeks with 4 antibiotics cocktail (Fig.1G) or PBS, followed by gavaged Allo B6 intestinal content or PBS. After antibiotics treatment and intestinal content gavage, mice received BMT. (B and C) Stool from BMT recipients and B6 mice were analyzed by 16S rRNA gene sequencing. PCoA (B) and inverse Simpson alpha diversity index of microbiome (C) are shown. (B6 N=5, Allo N=3, Allo with Ab N=4, Allo with Ab + stool N=4). Survival rate (D), clinical GVHD score (E), and pathological GVHD score of colon (F) are shown. (D) Allo: N=3, Allo with Ab: N=4, Allo with Ab+stool: N=4, B6: N=5. (E) Syn with Ab+stool: N=6, Allo: N=5, Allo with Ab: N=5, Allo with stool: N=5, Allo with Ab+stool: N=6. (F) Syn with Ab+stool: N=3, Allo: N=3, Allo with Ab: N=3, Allo with stool: N=3, Allo with Ab+stool: N=2. Two independent experiments were performed. One-way ANOVA analysis with Tukey post hoc test (C) and one-way ANOVA analysis with Dunn`s post hoc test (F) was used to determine significance (mean ± s.e.m.). **P < 0.01, ***P < 0.001. See also Figure S3.