CD40LG and clostridium difficile infection: Based on this rationale, our study aims to describe and validate a model of primary mild-C. difficile infection (CDI) in a naïve host, focusing on the kinetics of humoral (IgG, IgM) and mucosal (IgA) immune responses against toxins (TcdA/TcdB) and surface proteins (SlpA/FliC).