In our study, susceptible Rag1−/− mice were inoculated with A. muciniphila or BHI medium prior to T-cell transfer treatment, and Rag1−/− + Akk mice experienced a mitigated colitis phenotype and an increased percentage of colonic RORrt+ Treg cells compared with Rag1−/− + BHI mice, indicating the potential immune induction of colonic RORrt+ Treg cells by A. muciniphila in a specific context. The gene discussed is RAG1; the disease is colitis.