Novel antibody conjugates reactive with human carcinomas

Abstract

The present invention relates to novel antibodies, antibody fragments and antibody conjugates and single-chain immunotoxins reactive with human carcinoma cells. More particularly, the antibodies, conjugates and single-chain immunotoxins of the invention include: a murine monoclonal antibody, BR96; a human/murine chimeric antibody, ChiBR96; a F(ab′) 2 fragment of BR96; ChiBR96-PE, ChiBR96-LysPE40, ChiBR96 F(ab′) 2 -LysPE40 and ChiBR96 Fab′-LysPE40 conjugates and recombinant BR96 sFv-PE40 immunotoxin. These molecules are reactive with a cell membrane antigen on the surface of human carcinomas. The BR96 antibody and its functional equivalents, displays a high degree of selectivity for carcinoma cells and possess the ability to mediate antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activity. In addition, the antibodies of the invention internalize within the carcinoma cells to which they bind and are therefore particularly useful for therapeutic applications, for example, as the antibody component of antibody-drug or antibody-toxin conjugates. The antibodies also have a unique feature in that they are cytotoxic when used in the unmodified form, at specified concentrations.

1 . A monoclonal antibody BR96 produced by hybridoma ATCC HB 10036, or fragments thereof, and functional equivalents thereof having an antigen-binding region that competitively inhibits the immunospecific binding of monoclonal antibody BR96, having specific immunological reactivity with human carcinoma cells, said antibody characterized by being capable of internalizing within the carcinoma cells with which it reacts, mediating antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activity, and/or killing of said human carcinoma cells in the absence of host effector cells or complement.  
     
     
         2 - 44 . (canceled)  
     
     
         45 . An immunoconjugate that comprises an antibody joined to a therapeutic agent, wherein the antibody comprises an immunoglobulin or antigen-binding fragment thereof that competitively inhibits binding of the monoclonal antibody BR96, as produced by the hybridoma deposited with the ATCC and assigned Accession No. HB10036, to a carcinoma cell, and further wherein the antibody comprises a human Fc region.  
     
     
         46 . The immunoconjugate of  claim 45 , wherein the antibody is a monoclonal antibody or a fragment of a monoclonal antibody.  
     
     
         47 . The immunoconjugate of  claim 45 , wherein the antibody is a bifunctional antibody with a binding specificity for two different antigens.  
     
     
         48 . The immunoconjugate of  claim 45 , wherein the antibody is a chimeric antibody.  
     
     
         49 . The immunoconjugate of  claim 45 , wherein the antibody is a humanized antibody.  
     
     
         50 . The immunoconjugate of  claim 45  wherein the therapeutic agent is selected from the group consisting of a cytotoxin, an anti-tumor drug, a radioactive agent, a second antibody, and an enzyme.  
     
     
         51 . The immunoconjugate of  claim 50 , wherein the therapeutic agent is a cytotoxin that is a ribosome binding toxin.  
     
     
         52 . The immunoconjugate of  claim 51 , wherein the ribosome binding toxin is ricin A.  
     
     
         53 . The immunoconjugate of  claim 51 , wherein the therapeutic agent is an exotoxin.  
     
     
         54 . The immunoconjugate of  claim 53 , wherein the exotoxin is  Pseudomonas  exotoxin A.  
     
     
         55 . The immunoconjugate of  claim 53 , wherein the exotoxin is truncated to remove the cell-binding domain.  
     
     
         56 . The immunoconjugate of  claim 53 , wherein the amino terminus of the exotoxin has been modified to include a lysine amino acid residue.  
     
     
         57 . The immunoconjugate of  claim 50  which is purified.  
     
     
         58 . The immunoconjugate of any one of claims  45 - 49 , wherein the therapeutic agent is a pro-drug converting enzyme.  
     
     
         59 . The immunoconjugate of any one of claims  45 - 49 , wherein the therapeutic agent is a drug.  
     
     
         60 . The immunoconjugate of any one of claims  45 - 49  which is purified.  
     
     
         61 . A pharmaceutical composition comprising a pharmaceutically effective amount of the immunoconjugate of any one of claims  45 - 49 , and a pharmaceutically acceptable carrier.  
     
     
         62 . The pharmaceutical composition of  claim 61 , wherein the immunoconjugate is purified.  
     
     
         63 . A pharmaceutical composition comprising a pharmaceutically effective amount of the immunoconjugate of  claim 59 , and a pharmaceutically acceptable carrier.  
     
     
         64 . The pharmaceutical composition of  claim 63 , wherein the immunoconjugate is purified.  
     
     
         65 . A pharmaceutical composition comprising a pharmaceutically effective amount of the immunoconjugate of  claim 60 , and a pharmaceutically acceptable carrier.