Abstract: A novel member of the heregulin superfamily has been identified which is designated “&ggr;-HRG”. This molecule, secreted by human breast cancer MDA-MB-175 cells, leads to the formation of a constitutive active receptor complex and stimulates the growth of these cells in an autocrine manner. &ggr;-HRG polypeptide and nucleic acid are disclosed, together with various uses therefor (e.g. use of &ggr;-HRG nucleic acid for the recombinant production of &ggr;-HRG). &ggr;-HRG antagonists (e.g. neutralizing antibodies and antisense nucleic acid molecules) as well as uses therefor are also described.

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.

Abstract: The application concerns methods of treatment using anti-ErbB receptor antibody-maytansinoid conjugates, and articles of manufacture suitable for use in such methods. In particular, the invention concerns ErbB receptor-directed cancer therapies, using anri-ErbB receptor antibody-maytansinoid conjugates.

Abstract: Novel chimeric heteromultimer adhesins that bind the ligand of natural heteromultimeric receptors and uses therefor are disclosed. The chimeric molecules of the heteromultimer adhesins comprise an extracellular domain of a heteromultimeric receptor monomer and a multimerization domain for the stable interaction of the chimeric molecules in the adhesin. Specifically disclosed are heteromultimeric adhesins comprising the extracellular domains of ErbB2 and ErbB3 or ErbB2 and ErbB4. The chimeric ErbB heteromultimer adhesins of the present invention are useful as competitive antagonists or agonists of a neuregulin for the treatment of diseases such as various cancers.

Abstract: A novel member of the heregulin superfamily has been identified which is designated ".gamma.-HRG". This molecule, secreted by human breast cancer MDA-MB-175 cells, leads to the formation of a constitutive active receptor complex and stimulates the growth of these cells in an autocrine manner. .gamma.-HRG polypeptide and nucleic acid are disclosed, together with various uses therefor (e.g. use of .gamma.-HRG nucleic acid for the recombinant production of .gamma.-HRG). .gamma.-HRG antagonists (e.g. neutralizing antibodies and antisense nucleic acid molecules) as well as uses therefor are also described.

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.