Immunogenic peptides

Abstract

The invention provides relatively short immunogenic peptides, and biologically active variants thereof, associated with leukemia which elicit an immune response. Nucleic acids encoding the immunogenic peptides and antibodies specific for the peptides are also provided. The immunogenic peptides can be included in pharmaceutical compositions, such as cancer vaccines, and used for the treatment of cancer.

What is claimed is:  
     
         1 . An isolated leukemic antigen comprising a fragment of CD33 antigen (SEQ ID NO:4) or a variant thereof that is capable of stimulating a cytotoxic T-lymphocyte reaction wherein the fragment or variant thereof is 8, 9, 10, 11 or 12 amino acids in length.  
     
     
         2 . The isolated leukemic antigen of  claim 1  wherein the fragment of CD33 antigen is immunologically recognized by MHC restricted T-Lymphocytes that are HLA-A2.1 restricted.  
     
     
         3 . The isolated leukemic antigen of  claim 2  wherein the fragment of CD33 antigen comprises the amino acid sequence YLALCLCLI (SEQ ID NO: 1), AIISGDSPV (SEQ ID NO: 2) or YIISGDSPV (SEQ ID NO: 3).  
     
     
         4 . The isolated leukemic antigen of  claim 1  wherein the variant of the fragment of the CD33 antigen comprises the amino acid sequence YLALCLCLI (SEQ ID NO: 1), AIISGDSPV (SEQ ID NO: 2) or YIISGDSPV (SEQ ID NO: 3) with one or more conservative or nonconservative amino acid substitutions.  
     
     
         5 . The isolated leukemic antigen of  claim 1  in combination with one or more co-immunostimulatory molecules.  
     
     
         6 . A method for stimulating an immune effector cell response comprising contacting the isolated leukemic antigen of  claim 1  with an immune effector cell thereby stimulating the immune effector cell to respond against the isolated leukemic antigen.  
     
     
         7 . The method of  claim 6  wherein the immune effector cell is a naive T-lymphocyte or a memory T-lymphocyte.  
     
     
         8 . The method of  claim 6  further comprising contacting the isolated leukemic antigen with an antigen presenting cell wherein the antigen presenting cell contacts the isolated leukemic antigen with the immune effector cell.  
     
     
         9 . The method of  claim 8  wherein the antigen presenting cell is a dendritic cell or a T2 cell.  
     
     
         10 . The method of  claim 8  wherein the antigen presenting cell contacts the immune effector cell in vitro or in vivo.  
     
     
         11 . The method of  claim 10  wherein the isolated leukemic antigen comprises amino acid sequence YLALCLCLI (SEQ ID NO: 1), AIISGDSPV (SEQ ID NO: 2), or YIISGDSPV (SEQ ID NO: 3).  
     
     
         12 . The method of  claim 10  wherein the isolated leukemic antigen comprises a variant of the fragment of the CD33 antigen with the amino acid sequence YLALCLCLI (SEQ ID NO: 1), AIISGDSPV (SEQ ID NO: 2) or YIISGDSPV (SEQ ID NO: 3) having one or more conservative or nonconservative amino acid substitutions.  
     
     
         13 . The method of  claim 6  wherein contacting the isolated leukemic antigen with the immune effector cell occurs in the presence of an immunostimulatory molecule.  
     
     
         14 . An immune effector cell produced according to the method of  claim 6 .  
     
     
         15 . The immune effector cell of  claim 14  wherein the isolated leukemic antigen comprises the fragment of the CD33 antigen has the amino acid sequence YLALCLCLI (SEQ ID NO: 1), AIISGDSPV (SEQ ID NO: 2), YIISGDSPV (SEQ ID NO: 3) or a variant thereof having one or more conservative or nonconservative amino acid substitutions.  
     
     
         16 . An antigen presenting cell produced by contacting the isolated leukemic antigen of  claim 1  with an antigen presenting cell.  
     
     
         17 . The antigen presenting cell of  claim 16  wherein the isolated leukemic antigen comprises a fragment of the CD33 antigen with the amino acid sequence YLALCLCLI (SEQ ID NO: 1), AIISGDSPV (SEQ ID NO: 2), YIISGDSPV (SEQ ID NO: 3) or a variant thereof having one or more conservative or nonconservative amino acid substitutions.  
     
     
         18 . An isolated nucleic acid which encodes the isolated leukemic antigen of  claim 1 .  
     
     
         19 . An isolated nucleic acid which encodes the isolated leukemic antigen of  claim 3 .  
     
     
         20 . An isolated nucleic acid which encodes the isolated leukemic antigen of  claim 4 .  
     
     
         21 . A pharmaceutical composition comprising the isolated leukemic antigen of  claim 1 .  
     
     
         22 . An antibody, or functional fragment thereof, that is capable of binding the isolated leukemic agent of  claim 1.