Chemically modified peptides with improved immunogenicity
View Patent ↗The invention provides processes for improving the ability of a peptide to stimulate an immune response, comprising exposing the peptide to a chemical modifying agent. It further provides compositions comprising an antigenic peptide, wherein the peptide has been treated with a chemical modifying agent to improve its ability to stimulate an immune response. It also provides methods of stimulating an immune response in a mammal, comprising administering to the mammal an effective amount of a vaccine.
1. A composition comprising a cross-linked bacterial peptide, wherein the cross-linked bacterial peptide is derived from a non-toxic bacterial peptide treated with formaldehyde over a period of less than 144 hours in a reaction mix at a ratio (formaldehyde: reaction mix) of less than 2% (v/v or w/v) to introduce intra-molecular cross-linking into the non-toxic bacterial peptide,
wherein the non-toxic bacterial peptide is selected from the group consisting of:
(i) a non-toxic fragment of clostridial neurotoxin, wherein said non-toxic fragment is LH N ,
(ii) a non-toxic fragment comprising at least 200 contiguous amino acid residues of a Clostridium difficile toxin peptide, and
(iii) a non-toxic Clostridium difficile surface peptide; and
wherein the cross-linked bacterial peptide has enhanced efficacy for inducing a protective immune response as compared to the untreated non-toxic bacterial peptide from which it is derived.
2. The composition of claim 1 , wherein said non-toxic fragment of a Clostridium difficile toxin peptide is selected from the group consisting of a non-toxic fragment of a C. difficile Toxin A peptide, a non-toxic fragment of a C. difficile Toxin B peptide, or a non-toxic fragment of a C. difficile binary toxin peptide.
3. The composition of claim 1 , wherein the non-toxic bacterial peptide is LH N , and wherein the LH N is from botulinum type A toxin.
4. The composition of claim 3 , wherein the LH N comprises amino acid residues 2-871 of botulinum neurotoxin serotype A.
5. The composition of claim 3 or claim 4 , wherein the LH N comprises a Glu to Gln mutation as residue 224 and a His to Tyr mutation at residue 227.
6. The composition according to claim 1 , wherein the non-toxic bacterial peptide is LH N , and wherein the LH N comprises a protease cleavage site located between the L-chain and the H-chain.
7. The composition of claim 6 , wherein the protease cleavage site is located at a position that corresponds to a position between residues 440 and 455 of SEQ ID NO: 1.
8. The composition of claim 6 or claim 7 , wherein the protease cleavage site is a non-native clostridial neurotoxin cleavage site.
9. The composition of claim 1 , wherein the intra-molecular cross-linking comprises one or more methylene bonds.
10. The composition of claim 1 , wherein the cross-linked bacterial peptide is derived from a non-toxic bacterial peptide treated with formaldehyde over a period of less than 3 days, less than 2 days, or over a period of 36 hours or less.
11. The composition of claim 1 , wherein the cross-linked bacterial peptide is derived from a non-toxic bacterial peptide treated with formaldehyde in a reaction mix at a ratio (formaldehyde: reaction mix) of between 0.05% and 2% (v/v or w/v), or between 0.1% and 2% (v/v or w/v).
12. A vaccine comprising the composition of claim 1 and an adjuvant.
13. The vaccine of claim 12 , wherein the adjuvant is aluminium hydroxide.
14. The composition of claim 1 , wherein said non-toxic Clostridium difficile surface peptide is a Clostridium difficile Cwp 84 peptide.