Dual Variable Domain Immunoglobulin and Uses Thereof

1 - 65 . (canceled)

66 . A method of producing a binding protein, comprising culturing a host cell in culture medium, wherein said host cell comprises:

(a) a first nucleic acid encoding a first polypeptide chain of the binding protein that comprises formula 1: 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 heavy chain constant domain, X1 is a linker with the proviso that it is not CH1, X2 is an Fc region, and n is 0 or 1; and

(b) a second nucleic acid encoding a second polypeptide chain of the binding protein that comprises formula 2: VD1-(X1)n-VD2-C, wherein VD1 is a first light chain variable domain, VD2 is a second light chain variable domain, C is a light chain constant domain, X1 is a linker with the proviso that it is not CH1, and n is 0 or 1;

wherein the first nucleic acid is present on the same or a different expression vector as the second nucleic acid;

wherein the culturing of the host cell is under conditions sufficient to produce the first and second polypeptide chains; and

wherein one of the first polypeptide chain and one of the second polypeptide chain form a divalent form of the binding protein comprising two antigen binding sites, and wherein two of the first polypeptide chains and two of the second polypeptides form a tetravalent form of the binding protein comprising four antigen binding sites.

67 . The method of claim 66 , wherein 50%-75% of the binding protein produced is a dual specific tetravalent binding protein.

68 . The method of claim 66 , wherein 75%-90% of the binding protein produced is a dual specific tetravalent binding protein.

69 . The method of claim 66 , wherein 90%-95% of the binding protein produced is a dual specific tetravalent binding protein.

70 - 76 . (canceled)