Hybrid peptides modulate the immune response

A method for enhancing presentation of an MHC class II restricted antigenic epitope to a T cell, comprising:

• a) incorporating the MHC class II restricted antigenic epitope into an MHC class II antigen presentation enhancing hybrid polypeptide, the hybrid polypeptide comprising;
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising the MHC class II restricted antigenic epitope in the form of a polypeptide or peptidomimetic structure which binds into the antigenic peptide binding site of an MHC class II molecule;
• and
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• b) contacting under physiological conditions:
• i) the hybrid polypeptide of step a);
• ii) an MHC class II expressing antigen presenting cell;
• and
• iii) a T cell which is responsive to the presentation of the antigenic epitope by an MHC class II molecule of the antigen presenting cell.

A method for identifying a specific antigenic epitope which stimulates a predetermined T lymphocyte or clonal cells derived therefrom, using combinatorial chemistry procedures for peptide synthesis, comprising:

• a) providing a T lymphocyte or clonal cells derived therefrom;
• b) further providing a library of candidate compounds, with each candidate compound in the library being independently joined covalently at its N-terminus to a mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) or modifications thereof which retain antigen presentation enhancing activity, the candidate compound and the Ii key peptide being covalently linked by an intervening chemical structure to form a hybrid polypeptide, the intervening chemical structure being a joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• c) identifying hybrids from step b) which stimulate the T lymphocyte of step a) when presented in the context of an MHC class II molecule of an antigen presenting cell, the candidate compound of the specific hybrid identified corresponding to the specific antigenic epitope which stimulates the T lymphocyte.

A method for enhancing the range of MHC class II allelic presentation of an allelically restricted antigenic epitope, comprising:

• a) incorporating the antigenic epitope into an antigen presentation enhancing hybrid polypeptide, the hybrid polypeptide comprising;
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising the antigenic epitope;
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• b) contacting the antigen presentation enhancing hybrid polypeptide of step a) with antigen presenting cells and T lymphocytes which are responsive to the presentation of the antigenic epitope by an MHC class II molecule of the antigen presenting cells, under physiological conditions.

A method for identifying an antigenic epitope which exhibits a predetermined pattern of MHC class II restricted Th1 and Th2 stimulation, comprising:

• a) incorporating candidate antigenic epitopes into an antigen presentation enhancing hybrid polypeptide, the hybrid polypeptide comprising;
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising the antigenic epitope;
• and
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• b) screening for hybrid molecules which exhibit presentation activity with a predetermined pattern of MHC class II restricted Th1 and Th2 stimulation, by contacting the hybrid polypeptide under physiological conditions with:
• i) MHC class II expressing antigen presenting cell;
• and
• iii) either a Th1 or Th2 cell which is responsive to the presentation of antigenic epitope by an MHC class II molecule of the antigen presenting cell;
• and
• identifying hybrid polypeptides which stimulate the predetermined pattern of Th1 and Th2 cells through MHC class II presentation.

A method for modulating the immune response of an individual to a specific molecule, by enhancing the MHC class II presentation of an antigenic epitope of the molecule to T lymphocytes of the individual, comprising:

• a) providing an MHC class II antigen presentation enhancing hybrid polypeptide, comprising:
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising an antigenic epitope of the molecule, in the form of a polypeptide or peptidomimetic structure which binds into the antigenic peptide binding site of an MHC class II molecule;
• and
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• b) administering the antigen presentation enhancing hybrid polypeptide of step a) under conditions appropriate for the delivery of the hybrid to the antigen presenting cells of the individual.

A method for enhancing the immune response of an individual to a specific molecule, by enhancing the MHC class II presentation of an antigenic epitope of the molecule to T lymphocytes of the individual, comprising:

• a) obtaining a population of antigen presenting cells from the individual;
• b) treating those cells ex vivo with an MHC class II antigen presentation enhancing hybrid comprising:
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising an antigenic epitope of the molecule, in the form of a polypeptide or peptidomimetic structure, which binds into the antigenic peptide binding site of an MHC class II molecule;
• and
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• under conditions appropriate for binding of the hybrid to an MHC class II molecule of the antigen presenting cells;
• c) administering the antigen presenting cells produced by step b) to the individual under conditions which promote physical contact of the antigen presenting cells with T lymphocytes of the individual.

A method for identifying a compound which inhibits MHC class II antigen presentation, comprising:

• a) providing a library of candidate compounds which are predicted to be antigen binding site ligands, with each candidate compound in the library being independently joined covalently at its N-terminus to a mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) or modifications thereof which retain antigen presentation enhancing activity, the candidate compound and the Ii key peptide being covalently linked by an intervening chemical structure to form a candidate antigen presentation inhibiting hybrid polypeptide, the intervening chemical structure being a joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• b) screening the candidate antigen presentation inhibiting hybrid polypeptides of step a) by independently contacting each hybrid to the antigen presenting cell and T lymphocyte in a T lymphocyte activation assay, a correlation of hybrid contact with decreased T lymphocyte activation as compared to control reactions being a determination that the hybrid, and the candidate compound incorporate therein, are inhibitors of MHC class II antigen presentation.

A method for generally inhibiting presentation of MHC class II restricted antigenic epitopes to T lymphocytes, comprising contacting the following components under physiological conditions:

• a) an MHC class II expressing antigen presenting cell displaying on its surface a T lymphocyte-presented antigenic epitope;
• and
• b) an antigen presentation inhibiting hybrid polypeptide comprising:
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising an antigen binding site ligand or peptidomimetic structure which binds into the antigenic peptide binding site of an MHC class II molecule;
• and
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• c) a T lymphocyte which is responsive to the presentation of the antigenic epitope of part a) by an MHC class II molecule of the antigen presenting cell.

A therapeutic method for treating an individual for a disease associated with the generation of a non-beneficial immune response, by generally inhibiting MHC class II antigen presentation by antigen presenting cells of the individual, comprising:

• a) providing an MHC class II antigen presentation inhibiting hybrid polypeptide, comprising:
• i) an N-terminus comprising the mammalian Ii key peptide LRMKLPKPPKPVSKMR (SEQ ID NO:
• 1) and modifications thereof which retain antigen presentation enhancing activity;
• ii) a C-terminus comprising an antigen binding site ligand or peptidomimetic structure which binds into the antigenic peptide binding site of an MHC class II molecule;
• and
• iii) an intervening chemical structure covalently linking the N-terminal and C-terminal components of the hybrid, the chemical structure being a covalently joined group of atoms which when arranged in a linear fashion forms a flexible chain which extends up to the length of 20 amino acids likewise arranged in a linear fashion;
• and
• b) administering the hybrid of step a) to the individual under conditions appropriate for the delivery of the hybrid to the antigen presenting cells of the individual.