Patent ID: 8258268

Claim:
A binding protein comprising first and second polypeptide chains, wherein said first polypeptide chain comprises VD1-(X1)n-VD2-C-(X2)n, wherein VD1 is a first heavy chain variable domain, VD2 is a second heavy chain variable domain, C is a constant domain, X1 is a linker with the proviso that it is not a constant domain, and X2 is an Fc region; and said second polypeptide chain comprises VD1-(X1)n-VD2-C-(X2)n, wherein VD1 is a first light chain variable domain, VD2 is a second light chain variable domain, C is a constant domain, X1 is a linker with the proviso that it is not a constant domain, and X2 does not comprise an Fc region; wherein n is 0 or 1; and wherein said two polypeptide chains of said binding protein form two functional binding sites.