Patent ID: 8829175

Claim:
An episome comprising: (a) a first promoter operationally connected to a first nucleic acid encoding a first polypeptide comprising a polypeptide chain represented by the formula α-factor-a 1 -l 1 -a 2 -l 2 -a 3 , wherein a 1 , a 2 , and a 3 are immunoglobulin variable domains and l 1 and l 2 are peptide linkers, and wherein the first polypeptide comprises the amino acid sequence of h679VH (residues 8 to 126 of SEQ ID NO:1), (b) a second promoter operationally connected to a second nucleic acid encoding a polypeptide comprising a second polypeptide chain represented by the formula α-factor-b 1 -l 3 -b 2 -l 4 -b 3 , wherein b 1 , b 2 and b 3 are immunoglobulin variable domains and l 3 and l 4 are peptide linkers and the second polypeptide comprises the amino acid sequence of h679VK (residues 243 to 357 of SEQ ID NO:2), wherein said first and second polypeptide bind together form a complex comprising at least three antigen binding sites, wherein each of said antigen binding sites comprises a variable domain from said first polypeptide chain and a variable domain from said second polypeptide chain, wherein each of said polypeptides does not bind to itself to form an antigen binding site, wherein said first nucleic acid and said second nucleic acid are coexpressed when the episome is transformed into a host cell.