Binding molecules

Abstract

The present invention relates to the manufacture of a diverse repertoire of functional heavy chain-only antibodies that undergo affinity maturation, and uses thereof. The invention also relates to the manufacture and use of a diverse repertoire of class-specific heavy chain-only antibodies and to the manufacture and use of multivalent polypeptide complexes with antibody heavy chain functionality, preferably antibody heavy chain binding functionality, constant region effector activity and, optionally, additional effector functions. The present invention also relates to a method of generation of fully functional heavy chain-only antibodies in transgenic mice in response to antigen challenge. In particular, the present invention relates to a method for the generation of human antigen-specific, high affinity, heavy chain-only antibodies of any class, or mixture of classes and the isolation and expression of fully functional VH antigen-binding domains.

1 . A binding polypeptide complex comprising a dimer of a first heavy chain and a second heavy chain wherein:
 each heavy chain comprises two binding domains linked by flexible hinge regions one at the amino terminus and one at the carboxyl terminus of a dimerisation domain;   each dimerisation domain comprises at least C H 2, C H 3 and, optionally, C H 4 heavy chain antibody constant domains from any class of immunoglobulin heavy chain gene.   
     
     
         2 . The binding polypeptide complex of  claim 1  wherein all the binding domains are VH binding domains. 
     
     
         3 . The binding polypeptide complex of  claim 2  wherein all the VH binding domains are identical. 
     
     
         4 . The binding polypeptide complex of  claim 2  wherein the VH binding domains present at the amino termini of the first and second heavy chain are identical, and the VH binding domains present at the carboxyl termini of the first and second heavy chains are identical. 
     
     
         5 . The binding polypeptide complex of any one of  claims 2  to  4  wherein the VH binding domains comprise VH binding domains from any vertebrate, including camelid VHH binding domains. 
     
     
         6 . The binding polypeptide complex of any one of  claims 2  to  4  wherein the VH binding domains comprise human VH binding domains. 
     
     
         7 . The binding polypeptide complex of any one of  claims 2  to  4  wherein the VH binding domains are produced in transgenic mice in response to antigen challenge. 
     
     
         8 . The binding polypeptide complex of  claim 7 , wherein the VH heavy chain locus used comprises a camelid VHH gene segment and human D and J gene segments. 
     
     
         9 . The binding polypeptide complex of  claim 2  wherein the amino terminal binding domains are selected from the group consisting of mammalian, prokaryotic and viral cell adhesion molecules, cytokines, growth factors, receptor antagonists, receptor agonists, ligands, cell surface receptors, regulatory factors, structural proteins, structural peptides, serum proteins, secreted proteins, plasmalemma-associated proteins, viral antigens, bacterial antigens, protozoal antigens, parasitic antigens, lipoproteins, glycoproteins, hormones, neurotransmitters, clotting factors, and engineered single chain Fvs and combinations thereof. 
     
     
         10 . The binding polypeptide complex of  claim 2  wherein the carboxy terminal binding domains are selected from the group consisting of mammalian, prokaryotic and viral cell adhesion molecules, cytokines, growth factors, receptor antagonists, receptor agonists, ligands, cell surface receptors, regulatory factors, structural proteins, structural peptides, serum proteins, secreted proteins, plasmalemma-associated proteins, viral antigens, bacterial antigens, protozoal antigens, parasitic antigens, lipoproteins, glycoproteins, hormones, neurotransmitters, clotting factors, and engineered single chain Fvs and combinations thereof. 
     
     
         11 . An isolated polynucleotide encoding both heavy chains of a polypeptide binding complex according to any one of  claims 2  to  4 . 
     
     
         12 . A cloning or expression vector containing isolated polynucleotide of  claim 11  encoding the first and second heavy chains. 
     
     
         13 . A host cell transformed with an expression vector of  claim 12 . 
     
     
         14 . A method for the production of a binding polypeptide complex of any one of  claims 2  to  4 .