Microbiota of MAIT cell Deficient Mice Confer Resistance Against Clostridium difficile Infection

Background: Clostridium difficile (Cd) infection (CDI) typically occurs after antibiotic usage perturbs the gut microbiota. Mucosa-associated invariant T cells (MAIT) are found in the gut and their development is dependent on the host microbiome. MAIT cells help combat pulmonary infections; however, their role in gut infection is unknown. We hypothesized that MAIT cells would play a role in controlling CDI. To this end, wild-type (WT) and MR1-/- mice were treated with antibiotics and then infected with Cd spores. Results: Surprisingly, MR1-/- mice exhibited resistance to Cd colonization. 16S rRNA gene sequencing of feces revealed inherent differences in microbial composition. Conclusions: This colonization resistance was transferred from MR1-/- to WT mice via fecal microbiota transplantation, suggesting that MR1 and/or MAIT cells influence the microbiota, leading to CDI susceptibility.