Immunoconjugates and humanized antibodies specific for B-cell lymphoma and leukemia cells

Abstract

A chimeric LL2 monoclonal antibody is described in which the complementarity determining regions (CDRs) of the light and heavy chains of the murine LL2 anti-B-lymphoma, anti-leukemia cell monoclonal antibody has been recombinantly joined to the human kappa and IgG 1 constant region domains, respectively, which retains the immunospecificity and B-cell lymphoma and leukemia cell internalization capacity of the parental murine LL2 monoclonal antibody, and which has the potential of exhibiting reduced human anti-mouse antibody production activity. A humanized LL2 monoclonal antibody is described in which the CDRs of the light and heavy chains have been recombinantly joined to a framework sequence of human light and heavy chains variable regions, respectively, and subsequently linked to human kappa and IgG 1 constant region domains, respectively, which retains the immunospecificity and B-lymphoma and leukemia cell internalization capacities of the parental murine and chimeric LL2 monoclonal antibodies, and which has the potential for exhibiting reduced human anti-mouse antibody production activity. Vectors for producing recombinant chimeric and humanized chimeric monoclonal antibodies are provided. Isolated DNAs encoding the amino acid sequences of the LL2 variable light and heavy chain and CDR framework regions are described. Conjugates of chimeric and humanized chimeric LL2 antibodies with cytotoxic agents or labels find use in therapy and diagnosis of B-cell lymphomas and leukemias.

We claim:  
     
         1 . An isolated polynucleotide of FIG. 4A (Seq. ID NO. 3), said polynucleotide comprising the DNA sequence encoding the amino acid sequence of the light chain variable (VK) region of the LL2 monoclonal antibody (mAb).  
     
     
         2 . An isolated polynucleotide of FIG. 4B (Seq. ID NO. 4), said polynucleotide comprising the DNA sequence encoding the amino acid sequence of the heavy chain variable (VH) region of the LL2 mAb.  
     
     
         3 . An isolated polynucleotide of FIG. 5A (SEQ. ID NO.  5 ), said polynucleotide comprising the DNA sequence encoding the amino acid sequence of the hLL2 VK domain.  
     
     
         4 . An isolated polynucleotide of FIG. 5B (SEQ. ID NO. 6), said polynucleotide comprising the DNA sequence encoding the amino acid sequence of the hLL2 VH domain.  
     
     
         5 . A protein encoded by the polynucleotides of any one of  claims 1  to  4 , inclusive.  
     
     
         6 . An isolated complementarity determining region-1 (CDR1) polypeptide of the VK region of the LL2 mAb, comprising the amino acid sequence (SEQ ID NO. 19): 
 KSSQSVLYSANHKYLA    
     
     
         7 . An isolated CDR2 polypeptide of the VK region of LL2 mAb, comprising the amino acid sequence (SEQ ID NO. 20): 
 WASTRES    
     
     
         8 . An isolated CDR3 polypeptide of the VK region of the LL2 mAb, comprising the amino acid sequence (SEQ ID NO. 21): 
 HQYLSSWTF    
     
     
         9 . An isolated CDR1 polypeptide of the VH region of the LL2 mAb, comprising the amino acid sequence (SEQ ID NO. 22): 
 SYWLH    
     
     
         10 . An isolated CDR2 polypeptide of the VH region of the LL2 mAb, comprising the amino acid sequence (SEQ ID NO. 23): 
 YINPRNDYTEYNQNFKD    
     
     
         11 . An isolated CDR3 polypeptide of the VH region of the LL2 mAb, comprising the amino acid sequence (SEQ ID NO. 24): 
 RDITTFY    
     
     
         12 . The polynucleotide of  claim 1  inserted into a VKpBR plasmid.  
     
     
         13 . The polynucleotide of  claim 2  inserted into a VHpBS plasmid.  
     
     
         14 . A plasmid of  claim 12  or  claim 13 , further comprising an Ig promoter and a signal peptide sequence.  
     
     
         15 . A polynucleotide of  claim 1  or  claim 3  incorporated into a mammalian expression vector, designated LL2pKh, said vector further comprising an Ig promoter, a signal peptide DNA sequence, a genomic sequence of the human kappa constant region, an Ig enhancer, a kappa enhancer, and a marker gene.  
     
     
         16 . A polynucleotide of  claim 2  or  claim 4  incorporated into a mammalian expression vector, designated LL2pK1g, the vector further comprising an Ig promoter, a signal peptide DNA sequence, a genomic sequence of a human IgG1 constant region, an Ig enhancer and a marker gene.  
     
     
         17 . A cLL2 mAb, comprising the light chain and heavy chain chains of the mLL2 mAb linked to the human kappa and human IgG 1  constant regions, respectively.  
     
     
         18 . A hLL2 mAb, comprising a light chain and a heavy chain complementarity-determining region of a mLL2 mAb joined to a framework sequence of a human VK and human VH region, respectively, linked to human kappa and IgG 1  constant region domains, respectively, such that said hLL2 mAb retains substantially the B-lymphoma cell and leukemia cell targeting and cell internalization characteristics of the parent mLL2 antibody.  
     
     
         19 . A conjugate, comprising a cLL2 or hLL2 antibody or fragment thereof covalently bound to a diagnostic or therapeutic reagent.  
     
     
         20 . A conjugate of  claim 19 , wherein said diagnostic reagent comprises a label.  
     
     
         21 . A conjugate of  claim 19 , wherein said therapeutic reagent comprises a cytotoxic agent.  
     
     
         22 . A conjugate of  claim 19 , wherein said reagent is bound to said antibody or fragment thereof by means of a carbohydrate moiety of said antibody or fragment thereof.  
     
     
         23 . A method of treating a B-cell lymphoma or leukemia in a subject, comprising the step of administering to said subject a therapeutically effective amount of the conjugate of  claim 21  formulated in a pharmaceutically acceptable vehicle.  
     
     
         24 . A method of diagnosing a B-cell lymphoma or leukemia cell in a subject, comprising the steps of administering to said subject a diagnostically effective amount of the conjugate of  claim 20  formulated in a pharmaceutically acceptable vehicle, and detecting said label.