Peptide diagnostic agent for lyme disease
The present invention relates, e.g., to an isolated peptide consisting of the sequence MKKDDQIAAAIALRGMA (SEQ ID NO:1) or an active variant thereof, wherein the peptide or active variant can bind specifically to an antibody induced by a causative agent of Lyme disease (a pathogenic Borrelia ), e.g. in a sample from a subject having Lyme disease. Also disclosed are linear multimeric peptides that contain the peptide represented by SEQ ID NO:1 as well as one or more additional peptide epitopes from other Borrelia proteins that can also bind specifically to an antibody as above. Compositions and diagnostic kits comprising a peptide of the invention are described, as are diagnostic assays using the peptide(s).
1. An isolated peptide comprising the sequence MKKNDQI(V or G)AAIALRGVA (SEQ ID NO:64), wherein the peptide is no longer than 24 amino acids, and wherein the peptide can bind specifically to an antibody against a pathogenic Borrelia.
2. The isolated peptide of claim 1 , wherein the peptide comprises the sequence
MKKNDQIVAAIALRGVA (SEQ ID NO: 65) or
MKKNDQIGAAIALRGVA (SEQ ID NO: 66).
3. The isolated peptide of claim 1 , which consists of the sequence
MKKNDQI(V or G)AAIALRGVAK (SEQ ID NO: 73),
MKKNDQI(V or G)AAIALRGVAKD (SEQ ID NO: 74),
MKKNDQI(V or G)AAIALRGVAKDG (SEQ ID NO: 75),
MKKNDQI(V or G)AAIALRGVAKDGK (SEQ ID NO: 76),
MKKNDQI(V or G)AAIALRGVAKDGKF (SEQ ID NO: 77),
MKKNDQI(V or G)AAIALRGVAKDGKFA (SEQ ID NO: 78), or
MKKNDQI(V or G)AAIALRGVAKDGKFAV (SEQ ID NO: 79).
4. The isolated peptide of claim 1 , which consists of the sequence
MKKNDQIVAAIALRGVA (SEQ ID NO: 65) or
MKKNDQIGAAIALRGVA (SEQ ID NO: 66),
or which consists of the sequence of SEQ ID NO:65 or SEQ ID NO:66 plus an N-terminal C residue, which are SEQ ID NO:80 or SEQ ID NO:81, respectively.
5. A composition comprising an isolated peptide of claim 1 and one or more additional peptides which are specific for antibodies against the same or a different protein of the same or a different pathogenic Borrelia .
6. A diagnostic reagent comprising an isolated peptide of claim 1 and a system for detecting the peptide and/or a substrate for immobilizing the peptide.
7. A kit for diagnosing Lyme borreliosis, comprising an isolated peptide of claim 1 , and a system for detecting the peptide bound to an antibody to a pathogenic Borrelia protein and/or a substrate for immobilizing the peptide.
8. An isolated compound comprising the peptide of claim 1 linked to at least one further moiety, via a terminal amino acid linker or a chemical coupling agent.
9. The isolated compound of claim 8 , wherein the at least one further moiety is a second peptide that specifically recognizes an antibody against a pathogenic Borrelia , wherein the peptide and the second peptide are covalently linked.
10. The isolated compound of claim 8 , wherein the sequence of the peptide, including the further moiety, comprises VQEGVQQEGAQQPGGGMKKNDQI(V or G)AAIALRGVA (SEQ ID NO:68).
11. The isolated compound of claim 8 , wherein the sequence of the peptide, including the further moiety, consists of VQEGVQQEGAQQPGGGMKKNDQIVAAIALRGVA (SEQ ID NO:69) or CVQEGVQQEGAQQPGGGMKKNDQIVAAIALRGVA (SEQ ID NO:70).
12. The isolated compound of claim 8 , wherein the sequence of the peptide, including the further moiety, consists of VQEGVQQEGAQQPGGGMKKNDQIGAAIALRGVA (SEQ ID NO:71) or CVQEGVQQEGAQQPGGGMKKNDQIGAAIALRGVA (SEQ ID NO:72).
13. The isolated compound of claim 9 , wherein the peptide and the second peptide are separated from one another by a spacer of one to five Glycine or Alanine residues.
14. The isolated compound of claim 9 , wherein the second peptide comprises an epitope from Borrelia flagellin p41 or from Borrelia OspC.
15. The isolated compound of claim 14 , wherein the epitope from flagellin p41 has the sequence VQEGVQQEGAQQP (SEQ ID NO:18), or the epitope from OspC has the sequence PVVAESPKKP (SEQ ID NO:8).
16. A method for diagnosing Lyme disease in a subject, comprising contacting a sample from a subject suspected of having antibodies against a causative agent of Lyme disease with an isolated peptide of claim 1 , under conditions effective for the formation of a peptide-antibody complex, and detecting the presence of the peptide-antibody complex.
17. The method of claim 16 , wherein the peptide-antibody complex is detected by adding a binding partner which is labeled, or which can be labeled with a signal generating reagent.
18. The method of claim 17 , wherein the binding partner is an antibody attached to an enzyme, and a signal is generated when the enzyme reacts with a suitable substrate.
19. The method of claim 16 , wherein the detecting is performed with an ELISA assay.
20. The method of claim 16 , wherein the subject is a cat or a dog.
21. The method of claim 16 , wherein the subject is a human.