Lectin compositions and methods for modulating an immune response to an antigen

Abstract

The present invention provides a fusion polypeptide which can bind to a cell surface binding moiety (e.g., a carbohydrate) and serve as a ligand for a cell surface polypeptide, as well as a vector comprising a nucleic acid encoding for such a fusion polypeptide, and a host cell comprising such nucleic acid. The present invention also provides a composition comprising an antigen bearing target and such a fusion polypeptide, as well as a composition comprising a virus or a cell and such a fusion polypeptide. The present invention further relates to a method of modulating an immune response in an animal using such compositions.

1 . A nucleic acid molecule encoding a fusion polypeptide comprising:
 a first amino acid sequence which can bind to a carbohydrate and is HA; and   a second amino acid sequence comprising amino acids of GM-CSF.   
     
     
         2 . The nucleic acid molecule of  claim 1 , wherein said first amino acid sequence is N-terminal to said second amino acid sequence; or wherein said first amino acid sequence is C-terminal to said second amino acid sequence. 
     
     
         3 . The nucleic acid molecule of  claim 1 , wherein said GM-CSF binds to a human GM-CSF receptor. 
     
     
         4 . The nucleic acid molecule of  claim 1 , wherein said GM-CSF binds to a GM-CSF receptor of a cell selected from the group consisting of a leukocyte, an antigen presenting cell, a professional antigen presenting cell, and a dendritic cell. 
     
     
         5 . The nucleic acid molecule of  claim 1 , wherein said encoded fusion polypeptide further comprises a linker interposed between said first and second amino acid sequences. 
     
     
         6 . The nucleic acid molecule of  claim 5 , wherein the linker has the formula (Gly x Ser) n , wherein n is an integer between 1 and 15, and x is an integer between 1 and 10. 
     
     
         7 . The nucleic acid molecule of  claim 1 , wherein the encoded fusion polypeptide further comprises a secretory signal sequence. 
     
     
         8 . An expression vector containing the nucleic acid molecule of  claim 1 . 
     
     
         9 . The expression vector of  claim 8 , which is a mammalian expression vector. 
     
     
         10 . A host cell comprising the nucleic acid molecule of  claim 1 . 
     
     
         11 . The nucleic acid molecule of  claim 1 , wherein said second amino acid sequence comprises at least five contiguous amino acids of GM-CSF. 
     
     
         12 . A method of stimulating an immune response to an antigen in a subject comprising:
 administering to the subject a nucleic acid molecule encoding a fusion polypeptide comprising:
 a first amino acid sequence which can bind to a carbohydrate and is HA; and 
 a second amino acid sequence comprising amino acids of GM-CSF, 
   wherein an immune response to the antigen is stimulated in the subject following administration of the nucleic acid molecule.