The present invention relates to fusion proteins comprising fragments of toxin A and toxin B from Clostridium difficile, in particular the invention relates to a polypeptide comprising a first fragment and a second fragment, wherein (v) the first fragment is a toxin A repeating domain fragment； (vi) the second fragment is a toxin B repeating domain fragment； (vii) the first fragment comprises a first proximal end within a first repeat portion； (viii) the second fragment comprises a second proximal end within a second repeat portion； and wherein the first fragment and the second fragment are adjacent to one another and wherein the first repeat portion and the second repeat portion have sequence similarity to one another.
