ISOLATED NUCLEIC ACIDS, VECTORS AND HOST CELLS ENCODING ErbB3 ANTIBODIES

Abstract

Antibodies are disclosed which bind to ErbB3 protein and further possess any one or more of the following properties: an ability to reduce heregulin-induced formation of an ErbB2-ErbB3 protein complex in a cell which expresses ErbB2 and ErbB3; the ability to increase the binding affinity of heregulin for ErbB3 protein; and the characteristic of reducing heregulin-induced ErbB2 activation in a cell which expresses ErbB2 and ErbB3.

1 . An antibody which binds to ErbB3 protein and reduces heregulin-induced formation of an ErbB2-ErbB3 protein complex in a cell which expresses ErbB2 and ErbB3.  
     
     
         2 . The antibody of  claim 1  which further increases the binding affinity of heregulin for ErbB3 protein.  
     
     
         3 . The antibody of  claim 1  which further reduces heregulin-induced ErbB2 activation in the cell.  
     
     
         4 . The antibody of  claim 1  which is a monoclonal antibody.  
     
     
         5 . The antibody of  claim 1  which is humanized.  
     
     
         6 . The antibody of  claim 1  which is human.  
     
     
         7 . The antibody of  claim 1  which is an antibody fragment.  
     
     
         8 . The antibody fragment of  claim 8  which is a Fab.  
     
     
         9 . The antibody of  claim 1  which is labelled.  
     
     
         10 . The antibody of  claim 1  which is immobilized on a solid phase.  
     
     
         11 . An antibody which binds to ErbB3 protein and increases the binding affinity of heregulin for ErbB3 protein.  
     
     
         12 . An antibody which binds to ErbB3 protein and reduces heregulin-induced ErbB2 activation in a cell which expresses ErbB2 and ErbB3.  
     
     
         13 . An antibody which binds to ErbB3 protein and reduces heregulin binding thereto.  
     
     
         14 . The antibody of  claim 13  which further reduces heregulin-induced ErbB2 activation in a cell which expresses ErbB2 and ErbB3.  
     
     
         15 . The antibody of  claim 1  which binds to the epitope bound by the 8B8 antibody.  
     
     
         16 . The antibody of  claim 1  which has the complementarity determining regions of the 8B8 antibody.  
     
     
         17 . A composition comprising the antibody of  claim 1  and a pharmaceutically acceptable carrier.  
     
     
         18 . A cell line which produces the antibody of  claim 1 .  
     
     
         19 . The cell line of  claim 18  which is a hybridoma cell line producing the 8B8 antibody.  
     
     
         20 . A method for determining the presence of ErbB3 protein comprising exposing a cell suspected of containing the ErbB3 protein to the antibody of  claim 1  and determining binding of said antibody to the cell.  
     
     
         21 . A kit comprising the antibody of  claim 1  and instructions for using the antibody to detect the ErbB3 protein.