Multivalent and multispecific binding proteins, their manufacture and use
Polypeptides comprising a first domain, which comprises a binding region of an immunoglobulin heavy chain variable region, and a second domain, which comprises a binding region of an immunoglobulin light chain variable region, the domains being linked but incapable of associating with each other to form an antigen binding site, associate to form antigen binding multimers, such as dimers, which may be multivalent or have multispecificity. The domains may be linked by a short peptide linker or may be joined directly together. Bispecific dimers may have longer linkers. Methods of preparation of the polypeptides and multimers and diverse repertoires thereof, and their display on the surface of bacteriophage for easy selection of binders of interest, are disclosed, along with many utilities.
1. A nucleic acid molecule comprising a nucleotide sequence encoding a first polypeptide and a nucleotide sequence encoding a second polypeptide, wherein
said first polypeptide comprises a first domain which comprises a binding region of an immunoglobulin heavy chain variable region, and a second domain which comprises a binding region of an immunoglobulin light chain variable region, the first and second domains of the first polypeptide being linked by a polypeptide linker; and
said second polypeptide comprises a first domain which comprises a binding region of an immunoglobulin heavy chain variable region, a second domain which comprises a binding region of an immunoglobulin light chain variable region, the first and second domains of the second polypeptide being linked by a polypeptide linker;
the first domain of the first polypeptide and the second domain of the second polypeptide associating to form a first antigen binding site; and
the second domain of the first polypeptide and the first domain of the second polypeptide associating to form a second antigen binding site;
said first antigen binding site being different from said second antigen binding site; and
the polypeptide linker of the first polypeptide is of a length such that said first and second domains of said first polypeptide are incapable of associating with each other to form an antigen binding site.
2. The nucleic acid molecule of claim 1 wherein the polypeptide linker of the second polypeptide is of a length such that said first and second domains of said second polypeptide are incapable of associating with each other to form an antigen binding site.
3. The nucleic acid molecule of claim 1 wherein said polypeptide linker of the second polypeptide is a length selected from the group consisting of 9, 8, 7, 6, 5, 4, 3, 2 and 1 amino acids.
4. The nucleic acid molecule of claim 1 wherein the nucleic acid molecule comprises an RNA splice site between the nucleotide sequence which encodes the first domain and the nucleotide sequence which encodes the second domain of each of the first and second encoded polypeptides.
5. The nucleic acid molecule of claim 1 wherein the nucleic acid molecule comprises a site for recombination, wherein said site is between the nucleotide sequence encoding the first domain and the nucleotide sequence encoding the second domain of each of the first and second encoded polypeptides.
6. A vector comprising the nucleic acid molecule of claim 1 .
7. The vector of claim 6 comprising a nucleotide sequence necessary for expression of the first and second polypeptides.
8. The vector of claim 7 comprising a nucleotide sequence encoding a signal sequence for secretion of the first and second polypeptides.
9. The vector of claim 7 wherein the nucleic acid molecule comprises a site for recombination, wherein said site is between the nucleotide sequence encoding the first polypeptide and the nucleotide sequence encoding the second polypeptide.
10. A vector according to claim 6 wherein said vector further comprises nucleic acid encoding a surface component of a filamentous bacteriophage linked by a linker to said nucleic acid encoding said second polypeptide, said linker being selected from nucleic acid including an intervening suppressible stop codon and nucleic acid not including an intervening suppressible stop codon.
11. A host cell comprising the vector of claim 6 .
12. A host cell transfected with the vector of claim 10 wherein said linkage of nucleotide sequence encoding said second polypeptide to said nucleic acid encoding said surface component includes a suppressible stop codon and wherein said host cell is capable of co-expression of said first polypeptide, said second polypeptide and said surface component.
13. A host cell transfected with the vector of claim 10 wherein said linkage of nucleotide sequence encoding said second polypeptide to said nucleic acid encoding said surface component does not include a suppressible stop codon and wherein said host cell is capable of co-expression of said first polypeptide and a fusion protein comprising said second polypeptide and said surface component.
14. A method of making a dimer, which dimer comprises:
(i) a first polypeptide comprising a first domain which comprises a binding region of an immunoglobulin heavy chain variable region, and a second domain which comprises a binding region of an immunoglobulin light chain variable region, the first and second domains of the first polypeptide being linked by a polypeptide linker; and
(ii) a second polypeptide comprising a first domain which comprises a binding region of an immunoglobulin heavy chain variable region, a second domain which comprises a binding region of an immunoglobulin light chain variable region, the first and second domains of the second polypeptide being linked by a polypeptide linker;
the first domain of the first polypeptide and the second domain of the second polypeptide associating to form a first antigen binding site; and
the second domain of the first polypeptide and the first domain of the second polypeptide associating to form a second antigen binding site;
said first antigen binding site being different from said second antigen binding site;
the polypeptide linker of the first polypeptide being of a length such that said first and second domains of said first polypeptide are incapable of associating with each other to form an antigen binding site;
the method comprising culturing the host cell of claim 11 .
15. The method of claim 14 wherein the dimer is recovered from the host cell medium.
16. The method of claim 14 wherein the dimer is recovered from the host cell.
17. The method of claim 16 wherein the dimer is refolded from denaturing conditions.
18. The method of claim 14 wherein the dimer is recovered from the host cell periplasm.
19. The method of claim 14 wherein said dimer of said first and second polypeptides is selected by binding with antigen.
20. A vector comprising a nucleotide sequence encoding a first polypeptide and a nucleotide sequence encoding a second polypeptide, each of the first and second encoded polypeptides comprising a first domain which comprises a binding region of an immunoglobulin heavy chain variable region linked by a polypeptide linker to a second domain which comprises a binding region of an immunoglobulin light chain variable region;
the polypeptide linker of the first polypeptide being of a length such that said first and second domains of said first polypeptide are incapable of associating with each other to form an antigen binding site;
the first domain of the first polypeptide and the second domain of the second polypeptide associating to form a first antigen binding site;
the second domain of the first polypeptide and the first domain of the second polypeptide associating to form a second antigen binding site;
said first antigen binding site being different from said second antigen binding site;
the nucleotide sequence encoding the first polypeptide being linked to a nucleotide sequence encoding a signal sequence for export of the first polypeptide from a host cell upon expression;
the nucleotide sequence encoding the second polypeptide being linked to 1) a nucleotide sequence encoding a signal sequence for export of the second polypeptide from a host cell upon expression and 2) a nucleotide sequence encoding a surface component of a filamentous bacteriophage for display of the second polypeptide on the surface of a bacteriophage particle upon expression, the vector being capable of being packaged within a bacteriophage particle.
21. The vector of claim 20 wherein the polypeptide linker of the second polypeptide is of a length such that said first and second domains of said second polypeptide are incapable of associating with each other to form an antigen binding site.
22. A composition comprising a population of nucleic acid molecules as defined in claim 1 , wherein the polypeptides encoded by said population have a diverse repertoire of antigen binding activities.