VACCINES AGAINST CLOSTRIDIUM DIFFICILE AND METHODS OF USE
Attenuated microorganisms expressing Clostridium difficile antigen(s), and methods of using the same for vaccination of patients are disclosed The invention provides an attenuated microorganism expressing an immunogenic portion of a C difficile Toxin A C-terminal repeat region and/or a C difficile Toxin B C-terminal repeat region The microorganism is an attenuated Salmonella comprising an integrated gene expression cassette that directs the expression of the immunogenic peptide from an in vivo inducible promoter.
1 . An attenuated microorganism expressing an immunogenic peptide, the immunogenic peptide comprising an immunogenic portion of a Clostridium difficile Toxin A C-terminal repeat region and/or a C. difficile Toxin B C-terminal repeat region, wherein said microorganism induces an effective immune response against said immunogenic peptide when administered to a human patient.
2 . The attenuated microorganism of claim 1 , wherein the microorganism is an attenuated Salmonella comprising a gene expression cassette that directs the expression of the immunogenic peptide from an inducible promoter.
3 . The attenuated microorganism of claim 1 , wherein the immunogenic peptide is secreted from the microorganism via a secretion signal.
4 . The microorganism of claim 1 , wherein said microorganism induces mucosal immunity against said immunogenic peptide when orally administered to the patient.
5 . The microorganism of claim 1 , wherein the Toxin A C-terminal repeat region and/or the Toxin B C-terminal repeat region contains at least about 5 repeat units.
6 . The microorganism of claim 1 , wherein the Toxin A C-terminal repeat region and/or the Toxin B C-terminal repeat region contains at least about 15 repeat units.
7 . The microorganism of claim 1 , wherein the microorganism is an attenuated Salmonella having a deletion or inactivation of a gene involved in the biosynthesis of aromatic compounds.
8 . The microorganism of claim 7 , wherein the gene involved in the biosynthesis of aromatic compounds is aroC.
9 . The microorganism of claim 1 , wherein the microorganism is an attenuated Salmonella having a deletion or inactivation of a gene encoded on the Salmonella pathogenicity island 2 (SPI-2).
10 . The microorganism of claim 9 , wherein the gene encoded on SPI-2 is ssaV.
11 . The microorganism of claim 10 , wherein the attenuated Salmonella microorganism is derived from Salmonella enterica serovar Typhi ZH9.
12 . The microorganism of claim 11 , wherein the toxin A C-terminal repeat region and/or the Toxin B C-terminal repeat region is inserted at the aroC and/or ssaV gene deletion site.
13 . The microorganism of claim 1 , wherein the Clostridium difficile Toxin A C-terminal repeat region and/or the C. difficile Toxin B C-terminal repeat region are secreted via a ClyA secretion signal or a non-hemolytic derivative thereof.
14 . The microorganism claim 1 , wherein the polynucleotide encoding the Clostridium difficile Toxin A C-terminal repeat region and/or the C. difficile Toxin B C-terminal repeat region contains codons optimized for gene expression in Salmonella.
15 . The microorganism of claim 14 , wherein the polynucleotide has a G/C content of about 50%.
16 . The microorganism of claim 1 , wherein expression of the C. difficile Toxin A C-terminal repeat region and/or the C. difficile Toxin B C-terminal repeat region are controlled by a Salmonella ssaG promoter.
17 - 21 . (canceled)
22 . An attenuated Salmonella microorganism suitable for vaccination against Clostridium difficile , the microorganism comprising a gene expression cassette directing the expression of an immunogenic peptide from a Salmonella ssaG promoter, wherein the immunogenic peptide comprises an immunogenic portion of a C. difficile Toxin A C-terminal repeat region, and/or a C. difficile Toxin B C-terminal repeat region.
23 . A composition comprising the microorganism of claim 1 , and a pharmaceutically acceptable carrier and/or diluent.
24 . The composition of claim 23 , further comprising at least one adjuvant.
25 . A method for vaccinating a subject against C. difficile , comprising: administering the micoorganism of a claim 1 or the composition of claim 23 to said subject.
26 - 31 . (canceled)
32 . A recombinant peptide comprising a ClyA secretion signal, an immunogenic portion of a C. difficile Toxin A C-terminal repeat region, and/or an immunogenic portion of a C. difficile Toxin B C-terminal repeat region.
33 - 37 . (canceled)
38 . A polynucleotide encoding the recombinant peptide of claim 32 under control of a Salmonella ssaG promoter.
39 . The polynucleotide of claim 38 , wherein the polynucleotide is integrated at an aroC or ssaV gene deletion site of a Salmonella host cell.