The effect of gut microbiota and LPS-rich sterile diet on the weight and cellularity of lymphoid organs. (A) Germ-free mice have smaller spleens compared to conventional mice. (B) Gut microbiota and the LPS-rich diet drive the cellular expansion in MLNs and PPs. Results represent the mean (± SE) of at least 10 mice/group. Statistical analyses were performed using one-way analysis of variance (ANOVA) and a post-hoc comparison test (Tukey-Kramer). * indicates p < 0.05 and ** indicates p < 0.01.