Brun P et al. - This study evaluated the in vivo adjuvant activity of two peptides derived from Clostridium difficile: a fragment of the receptor-binding domain of toxin A (TxAC314) and a fragment of the 36 kDa surface-layer protein (SLP-36kDa) from strain C253.These studies provide insight into the ability of different C. difficile-derived peptides to differentially affect and polarize the activity of the immune system and on their potential use as adjuvants in newly developed vaccines.