Modified epitopes for boosting cd4+ t-cell responses

Abstract

The present invention relates to immunogenic peptides comprising a T-cell epitope. Said peptides are modified such that CD4+ T-cell responses are obtainable that arc much stronger than the CD4+ T-cell responses obtained with the same peptides not comprising said modification. In particular, the modification is the addition of a cysteine, insertion of a cysteine or mutation into a cysteine of a residue at a position adjacent to but outside the MIIC-binding site of the peptide. Further disclosed are the use of such modified peptides in treating, suppressing or preventing diseases such as infectious or allergic diseases and autoimmune diseases, in preventing or suppressing graft rejection, or in the eradication of tumor cells.

1 - 28 . (canceled) 
     
     
         29 . A method of treating an autoimmune or allergic disease or reducing an immune response that is neutralizing an allofactor, the method comprising administering to a subject in need thereof a therapeutically effective amount of an isolated peptide with a length of between 9 and 30 amino acids, wherein said peptide consists of:
 a) a natural MHC class II T cell epitope of a protein, said epitope comprising an 8 or 9 amino acid sequence that is capable of binding into the cleft of a human MHC class II molecule, and   b) an amino acid or a sequence of between 2 and 6 amino acids at the n-terminal and/or c-terminal side of the MHC class II T cell epitope of a), comprising a reducing cysteine residue separated by at most 5 amino acids from the n-terminal and/or c-terminal end, respectively, of the 8 or 9 amino acid sequence that is capable of binding into the cleft of the human MHC class II molecule, wherein said cysteine residue does not occur as part of a cysteine disulfide bridge, wherein said amino acid or said sequence of between 2 and 6 amino acids does not comprise a C-xx-[CST] or [CST]-xx-C redox motif sequence, and   wherein said cysteine residue does not occur in a sequence with the motif C-xx-[CST] or [CST]-xx-C.   
     
     
         30 . The method according to  claim 29 , wherein the amino acid or the sequence of between 2 and 6 amino acids defined in part b) contains only one cysteine. 
     
     
         31 . The method according to  claim 29 , wherein said peptide has a length of between 9 and 20 amino acids. 
     
     
         32 . The method of  claim 29 , wherein said isolated peptide is an artificial peptide wherein the sequence defined in part a) and b) differs from the sequence as occurring in the wild type sequence of said protein. 
     
     
         33 . The method of  claim 29 , wherein said protein is a self-antigen, an allergen, an allofactor or an allograft antigen. 
     
     
         34 . A method of modulating an immune response to a protein, the method comprising administering to a subject in need thereof a therapeutically effective amount of an isolated peptide with a length of between 9 and 30 amino acids, wherein said peptide consists of:
 a) a natural MHC class II T cell epitope of the protein, said epitope comprising an 8 or 9 amino acid sequence that is capable of binding into the cleft of a human MHC class II molecule, and   b) an amino acid or a sequence of between 2 and 6 amino acids at the n-terminal and/or c-terminal side of the MHC class II T cell epitope of a), comprising a reducing cysteine residue separated by at most 5 amino acids from the n-terminal and/or c-terminal end, respectively, of the 8 or 9 amino acid sequence that is capable of binding into the cleft of the human MHC class II molecule, wherein said cysteine residue does not occur as part of a cysteine disulfide bridge,   wherein said amino acid or said sequence of between 2 and 6 amino acids does not comprise a C-xx-[CST] or [CST]-xx-C redox motif sequence, and   wherein said cysteine residue does not occur in a sequence with the motif C-xx-[CST] or [CST]-xx-C.   
     
     
         35 . The method of  claim 34 , wherein the amino acid or the sequence of between 2 and 6 amino acids defined in part b) contains only one cysteine. 
     
     
         36 . The method of  claim 34 , wherein said peptide has a length of between 9 and 20 amino acids. 
     
     
         37 . The method of  claim 34 , wherein said isolated peptide is an artificial peptide wherein the sequence defined in part a) and b) differs from the sequence as occurring in the wild type sequence of said protein. 
     
     
         38 . The method of  claim 34 , wherein said protein is a self-antigen, an allergen, an allofactor or an allograft antigen. 
     
     
         39 . An in vitro method for preparing a population of activated non-cytolytic CD4+ T cells, the method comprising administering to a population of peripheral blood cells an effective amount of an isolated peptide with a length of between 9 and 30 amino acids, wherein said peptide consists of:
 a) a natural MHC class II T cell epitope of the protein, said epitope comprising an 8 or 9 amino acid sequence that is capable of binding into the cleft of a human MHC class II molecule, and   b) an amino acid or a sequence of between 2 and 6 amino acids at the n-terminal and/or c-terminal side of the MHC class II T cell epitope of a), comprising a reducing cysteine residue separated by at most 5 amino acids from the n-terminal and/or c-terminal end, respectively, of the 8 or 9 amino acid sequence that is capable of binding into the cleft of the human MHC class II molecule, wherein said cysteine residue does not occur as part of a cysteine disulfide bridge,   wherein said amino acid or said sequence of between 2 and 6 amino acids does not comprise a C-xx-[CST] or [CST]-xx-C redox motif sequence, and   wherein said cysteine residue does not occur in a sequence with the motif C-xx-[CST] or [CST]-xx-C.   
     
     
         40 . The method of  claim 39 , wherein the amino acid or the sequence of between 2 and 6 amino acids defined in part b) contains only one cysteine. 
     
     
         41 . The method of  claim 39 , wherein said peptide has a length of between 9 and 20 amino acids. 
     
     
         42 . The method of  claim 39 , wherein said isolated peptide is an artificial peptide wherein the sequence defined in part a) and b) differs from the sequence as occurring in the wild type sequence of said protein. 
     
     
         43 . The method of  claim 39 , wherein said protein is a self-antigen, an allergen, an allofactor or an allograft antigen.