Compositions and methods relating to a mutant
In one aspect, the invention relates to an immunogenic composition that includes a mutant Clostridium difficile toxin A and/or a mutant Clostridium difficile toxin B. The mutant toxin may include a glucosyltransferase domain having at least one mutation and a cysteine protease domain having at least one mutation, relative to the corresponding wild-type C. difficile toxin. The mutant toxins may include at least one amino acid that is chemically crosslinked. In another aspect, the invention relates to methods and compositions for use in culturing Clostridium difficile and in producing C. difficile toxins.
1. A method of eliciting an immune response in a mammal, comprising administering an effective amount of a composition comprising a lyophilized polypeptide comprising the amino acid sequence set forth in any one of SEQ ID NOs: 185-194; a saponin adjuvant; and a stabilizer selected from the group consisting of starch, dextran, sucrose, trehalose, lactose, and glucose; wherein the composition does not comprise formaldehyde; and wherein the method comprises administering at least two doses of the composition to the mammal.
2. The method according to claim 1 , wherein the second dose is about 30 days after the first dose.
3. The method according to claim 1 , wherein the second dose is about 60 days after the first dose.
4. The method according to claim 1 , wherein the second dose is about 180 days after the first dose.
5. The method according to claim 1 , wherein the dose is administered intramuscularly.