Synthetic bi-epitope compound

Abstract

A bi-epitope compound of formula (I): in which (i) E1 and E2, which may be identical or different, each independently represent a peptide sequence comprising at least one epitope of an analyte, (ii) X and Y, which may be identical or different, each independently represent a linker arm, (iii) the carrier molecule is soluble, and (iv) Z represents an amino acid derivative that had a thiol function before the bonding thereof with the carrier molecule.

1 . A bi-epitope compound of formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         E1 and E2, which may be identical or different, each independently represent a peptide sequence comprising at least one epitope of an analyte; 
         X and Y, which may be identical or different, each independently represent a linker arm; 
         the carrier molecule is soluble; and 
         Z represents an amino acid derivative that had a thiol function before the bonding thereof with the carrier molecule. 
       
     
     
         2 . The bi-epitope compound of  claim 1 , wherein:
 X and Y each independently represent an amino acid derivative forming two peptide bonds —CO—NH—, one with E1 or E2 and the other with Z;   the carrier molecule is a soluble protein having a molecular weight between 20 kDa and 700 kDa;   Z represents a cysteine derivative, a homocysteine derivative, or a penicillamine derivative; and   Z forms three bonds such that Z forms the peptide bond —CO—NH— with each of the linker arms X and Y and forms a bond with the carrier molecule.   
     
     
         3 . The bi-epitope compound of  claim 2 , wherein the carrier molecule is bovine serum albumin. 
     
     
         4 . The bi-epitope compound of  claim 2 , wherein the carrier molecule is immunoglobulin G. 
     
     
         5 . The bi-epitope compound of  claim 2 , wherein E1 and E2 each independently represent a peptide sequence comprising at least one cardiac troponin I epitope. 
     
     
         6 . The bi-epitope compound of  claim 2 , wherein E1 and E2 each independently represent a peptide sequence comprising at least one prodefensin-A6 epitope. 
     
     
         7 . The bi-epitope compound of  claim 2 , wherein X and Y each independently comprise one to six amino acid residues. 
     
     
         8 . The bi-epitope compound of  claim 2 , wherein the bond that Z forms with the carrier molecule is a thioether bond. 
     
     
         9 . The bi-epitope compound of  claim 2 , wherein the bi-epitope compound is in solution in water, in a buffer, or in a biological fluid. 
     
     
         10 . The bi-epitope compound of  claim 2 , wherein the molecular weight of the carrier molecule is between 60 kDa and 250 kDa. 
     
     
         11 . The bi-epitope compound of  claim 2 , wherein E1-X-Z-Y-E2 is a peptide that is no more than 100 amino acid residues in length. 
     
     
         12 . The bi-epitope compound of  claim 2 , wherein E1-X-Z-Y-E2 is a peptide that is 20 to 30 amino acid residues in length. 
     
     
         13 . The bi-epitope compound of  claim 2 , wherein E1-X-Z-Y-E2 is a peptide that is 25 to 27 amino acid residues in length. 
     
     
         14 . The bi-epitope compound of  claim 2 , wherein E1 and E2 each independently represent a peptide sequence comprising at least one epitope selected from the group consisting of SEQ ID NOS: 1-23. 
     
     
         15 . The bi-epitope compound of  claim 14 , wherein the at least one epitope is selected from the group consisting of SEQ ID NOS: 1-3. 
     
     
         16 . The bi-epitope compound of  claim 14 , wherein the at least one epitope is selected from the group consisting of SEQ ID NOS: 4-23. 
     
     
         17 . The bi-epitope compound of  claim 14 , wherein X and Y each independently represent a dimer or a trimer of 8-amino-3,6-dioxaoctanoic acid, SEQ ID NO: 25, or SEQ ID NO: 26. 
     
     
         18 . The bi-epitope compound of  claim 14 , wherein Z represents a cysteine derivative. 
     
     
         19 . A kit comprising one or more binding partners and the bi-epitope compound of  claim 2 . 
     
     
         20 . The kit of  claim 19 , wherein the binding partners are selected from the group consisting of antibodies, antibody fragments, nanofitins, receptors, aptamers, and DARPins. 
     
     
         21 . A process for detecting an analyte in a test sample that may contain the analyte, comprising:
 bringing the test sample into contact with one or more binding partners for the analyte during an immunoassay test;   verifying the validity of the immunoassay test by a validity verification test that comprises bringing the bi-epitope compound of  claim 2 , as a positive control, into contact with the one or more binding partners for the analyte;   reading the immunoassay test if the validity verification test is positive; and   determining the presence of the analyte in the test sample when a signal obtained by the immunoassay test is greater than a detection threshold of the immunoassay test.   
     
     
         22 . A process for quantifying an analyte in a test sample that may contain the analyte, comprising:
 bringing the test sample into contact with one or more binding partners for the analyte during an immunoassay test;   verifying the validity of the immunoassay test by a validity verification test that comprises bringing a positive control into contact with the one or more binding partners for the analyte;   reading the immunoassay test if the validity verification test is positive; and   determining an amount of the analyte in the test sample by comparison of a signal of the immunoassay test with a standard curve obtained beforehand using the bi-epitope compound of  claim 2 .   
     
     
         23 . A process for quantifying an analyte in a test sample that may contain the analyte, comprising:
 bringing the test sample into contact with one or more binding partners for the analyte during an immunoassay test;   verifying the validity of the immunoassay test by a validity verification test that comprises bringing the bi-epitope compound of  claim 2 , as a positive control, into contact with the one or more binding partners for the analyte;   reading the immunoassay test if the validity verification test is positive; and   determining an amount of the analyte in the test sample by comparison of a signal of the immunoassay test with a standard curve.