DELIVERY OF NONTOXIC FRAGMENTS OF CLOSTRIDIUM-DIFFICILE TOXIN-A TO THE MUCOSAL IMMUNE-SYSTEM

Polymerase chain reaction fragments coding for 8, 14, 20 and 36 C-term inal repeats from Clostridium difficile toxin A were expressed as fusi ons to fragment C of tetanus toxin. These fusions were expressed withi n a rationally attenuated Salmonella typhimurium htrA mutant which has been shown to be effective at delivering heterologous antigens to the gastro-intestinal mucosa. The larger fragments retained their recepto r-binding properties, and the construct containing 14 repeats induced an antitoxin A serum response within mice.