Cytokine immunoconjugates

Abstract

Immunoconjugates for the selective delivery of a cytokine to a target cell are disclosed. The immunoconjugates are comprised of an immunoglobulin heavy chain having a specificity for the target cell, such as a cancer or virus-infected cell, and a cytokine, such as lymphotoxin, tumor necrosis factor alpha, interleukin-2, or granulocyte-macrophage colony stimulating factor, joined via Aits amino terminal amino acid to the carboxy-Aterminus of the immunoglobulin. Nucleic acid sequences encoding these immunoconjugates and methods of their preparation by genetic engineering techniques are also disclosed.

What is claimed is:  
     
         1 . A chimeric immunoglobulin (Ig) chain comprising an Ig heavy chain and a cytokine.  
     
     
         2 . The chimeric Ig chain of  claim 1 , wherein the Ig heavy chain is joined at its carboxy-terminus by a peptide bond to the amino terminal amino acid of the cytokine.  
     
     
         3 . The chimeric Ig chain of  claim 1 , wherein the Ig heavy chain comprises CH1, CH2, and CH3 domains.  
     
     
         4 . The chimeric Ig chain of  claim 1 , wherein a proteolytic cleavage site is located between the Ig heavy chain and the cytokine.  
     
     
         5 . The chimeric Ig chain of  claim 1 , wherein the variable region is derived from a mouse and the constant region is derived from a human antibody.  
     
     
         6 . The chimeric Ig chain of  claim 1 , wherein the variable region of the Ig heavy chain is derived from an Ig specific for a cancer cell or a virus-infected cell.  
     
     
         7 . The conjugate of  claim 6 , wherein the variable region is derived from an Ig specific for a tumor-associated antigen or a viral antigen.  
     
     
         8 . The chimeric Ig chain of  claim 1 , wherein the cytokine is tumor necrosis factor alpha.  
     
     
         9 . The chimeric Ig chain of  claim 1 , wherein the cytokine is interleukin-2.  
     
     
         10 . The chimeric Ig chain of  claim 1 , wherein the cytokine is a lymphokine.  
     
     
         11 . The chimeric Ig chain of  claim 10 , wherein the lymphokine is a lymphotoxin.  
     
     
         12 . The chimeric Ig chain of  claim 10 , wherein the lymphokine is granulocyte-macrophage colony stimulating factor.  
     
     
         13 . The chimeric Ig chain of  claim 10 , wherein the lymphokine is a protein which forms a dimeric or multimeric structure.  
     
     
         14 . A chimeric immunoglobulin (Ig) chain comprising an Ig heavy chain having a variable region specific for a target cell antigen and a heavy chain including CH1, CH2, and CH3 domains, joined, through a peptide bond, to the amino terminus amino acid of a cytokine.  
     
     
         15 . The chimeric Ig chain of  claim 14 , wherein the cytokine is selected from the group consisting of lymphotoxin, interleukin-2, tumor necrosis factor, and granulocyte-macrophage colony stimulating factor.  
     
     
         16 . A cytokine immunoconjugate comprising: 
 (a) a chimeric immunoglobulin (Ig) chain including an Ig heavy chain having a variable region specific for a cancer cell or virus-infected cell, joined at the carboxy-terminus of its constant region by a peptide bond to a cytokine; and    (b) an Ig light chain having a variable region specific for the cancer or virus-infected cell,    said heavy and light chains forming a functional antigen-binding site.    
     
     
         17 . The immunoconjugate of  claim 16 , wherein the chimeric heavy chain has a constant region comprising CH1, CH2, and CH3 domains.  
     
     
         18 . The immunoconjugate of  claim 16 , wherein the cytokine is interleukin-2.  
     
     
         19 . The immunoconjugate of  claim 16 , wherein the cytokine is tumor necrosis factor alpha.  
     
     
         20 . The immunoconjugate of  claim 16 , wherein the cytokine is a lymphokine.  
     
     
         21 . The immunoconjugate of  claim 20 , wherein the lymphokine is lymphotoxin.  
     
     
         22 . The immunoconjugate of  claim 20 , wherein the lymphokine is granulocyte-macrophage stimulating factor.  
     
     
         23 . A nucleic acid encoding a chimeric immunoglobulin (Ig) chain comprising an Ig heavy chain and a cytokine.  
     
     
         24 . The nucleic acid of  claim 23  which is DNA.  
     
     
         25 . The nucleic acid of  claim 23 , wherein the Ig heavy chain comprises CH1, CH2, and CH3 domains.  
     
     
         26 . The nucleic acid of  claim 23 , wherein the variable region is derived from an Ig specific for a cancer cell or a virus-infected cell.  
     
     
         27 . The nucleic acid of  claim 26 , wherein the variable region is derived from an Ig specific for a tumor-associated antigen or a viral antigen.  
     
     
         28 . The nucleic acid of  claim 23 , wherein a proteolytic cleavage site is located between the Ig heavy chain and the cytokine.  
     
     
         29 . The nucleic acid of  claim 23 , wherein the variable region is derived from a mouse antibody and the constant region is derived from a human antibody.  
     
     
         30 . The nucleic acid of  claim 23 , wherein the cytokine is interleukin-2.  
     
     
         31 . The nucleic acid of  claim 23 , wherein the cytokine is tumor necrosis factor alpha.  
     
     
         32 . The nucleic acid of  claim 23 , wherein the cytokine is a lymphokine.  
     
     
         33 . The nucleic acid of  claim 32 , wherein the lymphokine is a protein which forms a dimeric or multimeric structure.  
     
     
         34 . The nucleic acid of  claim 32 , wherein the lymphokine is a lymphotoxin.  
     
     
         35 . The nucleic acid of chain 32, wherein the lymphokine is granulocyte-macrophage colony stimulating factor.  
     
     
         36 . A recombinant DNA encoding a chimeric immunoglobulin (Ig) chain, comprising an Ig heavy chain having a variable region specific for a target cell antigen and heavy chain having CH1, CH2 and CH3 domain, joined, through a peptide bond, to the amino terminal amino acid of a cytokine.  
     
     
         37 . The DNA construct of  claim 35 , wherein the cytokine is selected from the group consisting of tumor necrosis factor alpha, interleukin-2, lymphotoxin, and granulocyte-macrophage colony stimulating factor.  
     
     
         38 . A cell line transfected with the nucleic acid of  claim 23 .  
     
     
         39 . A cell line transfected with the nucleic acid of  claim 36 .  
     
     
         40 . A cell line of  claim 23  which is a myeloma cell line.  
     
     
         41 . A cell line of  claim 36  which is a myeloma cell line.  
     
     
         42 . A method of selectively delivering a cytokine to a target cell, comprising: 
 (a) providing a cytokine immunoconjugate including: 
 a chimeric immunoglobulin (Ig) chain comprising an Ig heavy chain having a variable region specific for the target cell joined at the carboxy terminus of its constant region by a peptide bond to a cytokine, and  
 an Ig light chain combined with the chimeric Ig heavy chain, forming a functional antigen-binding site; and  
   (b) administering to a subject harboring the target cell an amount of the immunoconjugate sufficient to reach the target cell.    
     
     
         43 . The method of  claim 42  wherein said target cell is a cancer cell or a virus-infected cell.  
     
     
         44 . The method of  claim 42 , wherein the chimeric heavy chain has a constant region comprising CH1, CH2, and CH3 domains.  
     
     
         45 . The method of  claim 42 , wherein the cytokine is selected from the group consisting of lymphotoxin, interleukin-2, tumor necrosis factor alpha, and granulocyte-macrophage colony stimulating factor.