Immunostimulatory oligonucleotides with modified bases and methods of use thereof

Abstract

Immunomodulatory oligonucleotide compositions are disclosed. These oligonucleotides comprise an immunostimulatory hexanucleotide sequence comprising a modified cytosine. These oligonucleotides can be administered in conjunction with an immunomodulatory peptide or antigen. Methods of modulating an immune response upon administration of the oligonucleotide comprising a modified immunostimulatory sequence are also disclosed.

1 . An immunomodulatory polynucleotide comprising an immunostimulatory sequence (ISS) comprising 5′-mC, G-3′, wherein mC is a cytosine modified with an electron-withdrawing group at position C-6. 
     
     
         2 . The immunomodulatory polynucleotide of  claim 1 , wherein the electron-withdrawing group is selected from a halogen, hydroxy or nitro group. 
     
     
         3 . The immunomodulatory polynucleotide of  claim 1 , wherein the mC is 6-azacytosine. 
     
     
         4 . The immunomodulatory polynucleotide of  claim 1 , wherein the ISS comprises the sequence 5′-Purine, Purine, mC, G, Pyrimidine, Pyrimidine-3′. 
     
     
         5 . The immunomodulatory polynucleotide of  claim 1 , wherein the polynucleotide comprises a modified phosphate linkage. 
     
     
         6 . An immunomodulatory polynucleotide comprising an immunostimulatory sequence (ISS) comprising 5′-mC, G-3′, wherein mC is a modified cytosine selected from the group consisting of 5-hydroxycytosine, 5-nitrocytosine and 5,6-dihydroxycytosine. 
     
     
         7 . The immunomodulatory polynucleotide of  claim 6 , wherein the ISS comprises the sequence 5′-Purine, Purine, mC, G, Pyrimidine, Pyrimidine-3′. 
     
     
         8 . The immunomodulatory polynucleotide of  claim 7 , wherein the ISS comprises the sequence 5′-Purine, Purine, mC, G, Pyrimidine, Pyrimidine, Cytosine, Cytosine-3′. 
     
     
         9 . The immunomodulatory polynucleotide of  claim 6 , wherein the polynucleotide comprises a modified phosphate linkage. 
     
     
         10 . An immunomodulatory polynucleotide comprising an immunostimulatory sequence (ISS) comprising 5′-Purine, Purine, mC, G, Pyrimidine, Pyrimidine-3′, wherein mC is a cytosine modified with an electron-withdrawing group at position C-5. 
     
     
         11 . The immunomodulatory polynucleotide of  claim 10 , wherein the electron-withdrawing group is selected from a hydroxy or nitro group. 
     
     
         12 . The immunomodulatory polynucleotide of  claim 10 , wherein the polynucleotide comprises a modified phosphate linkage. 
     
     
         13 . An immunomodulatory polynucleotide comprising an immunostimulatory sequence (ISS) comprising 5′-T, mC, G-3′, wherein mC is a cytosine modified with an electron-withdrawing group at position C-5. 
     
     
         14 . The immunomodulatory polynucleotide of  claim 13 , wherein the electron-withdrawing group is selected from a hydroxy or nitro group. 
     
     
         15 . The immunomodulatory polynucleotide of  claim 13 , wherein the polynucleotide comprises a modified phosphate linkage. 
     
     
         16 . An immunomodulatory composition comprising
 an immunomodulatory polynucleotide comprising an immunostimulatory sequence (ISS) comprising 5′-mC, G-3′, wherein mC is a cytosine modified with an electron-withdrawing group at position C5 or C6;   and an antigen.   
     
     
         17 . The immunomodulatory composition of  claim 16 , wherein the electron-withdrawing group is selected from a hydroxy or nitro group. 
     
     
         18 . The immunomodulatory composition of  claim 16 , wherein mC is selected from the group consisting of 5-bromocytosine, 5-hydroxycytosine, 5-nitrocytosine, 5,6-dihydroxycytosine and 6-azacytosine. 
     
     
         19 . An immunomodulatory composition of  claim 16 , wherein the antigen is selected from the group consisting of peptides, glycoproteins, polysaccharides, and lipids. 
     
     
         20 . An immunomodulatory composition of  claim 16 , wherein the antigen is linked to the immunomodulatory polynucleotide. 
     
     
         21 . An immunomodulatory composition of  claim 16 , further comprising an adjuvant. 
     
     
         22 . A method of modulating an immune response comprising administration of an antigen and an immunomodulatory polynucleotide, wherein the immunomodulatory polynucleotide comprises an immunostimulatory sequence (ISS) comprising 5′-mC, G-3′, wherein mC is a cytosine modified with an electron-withdrawing group at position C5 or C6. 
     
     
         23 . The method of  claim 22 , wherein the electron-withdrawing group is selected from a halogen, hydroxy or nitro group. 
     
     
         24 . The method of  claim 22 , wherein mC is selected from the group consisting of 5-bromocytosine, 5-hydroxycytosine, 5-nitrocytosine, 5,6-dihydroxycytosine and 6-azacytosine. 
     
     
         25 . The method of  claim 22 , wherein the modulating of an immune response comprises induction of a Th1-type response. 
     
     
         26 . The method of  claim 22 , wherein the polynucleotide comprises the sequence SEQ ID NO:2. 
     
     
         27 . The method of  claim 22 , wherein the polynucleotide comprises the sequence SEQ ID NO:5. 
     
     
         28 . The method of  claim 22 , wherein the polynucleotide comprises the sequence SEQ ID NO:6. 
     
     
         29 . A method of modulating an immune response comprising administration of an immunomodulatory polynucleotide according to  claim 1 . 
     
     
         30 . A method of modulating an immune response comprising administration of an immunomodulatory polynucleotide according to  claim 6 . 
     
     
         31 . A method of modulating an immune response comprising administration of an immunomodulatory polynucleotide according to  claim 10 . 
     
     
         32 . A method of modulating an immune response comprising administration of an immunomodulatory polynucleotide according to  claim 16 .