Patent ID: 7129330

Claim:
A bispecific tetravalent homodimeric F v antibody formed by two single-chain F v monomers, each of said F v monomers having at least four variable domains, wherein said four variable domains are V H -A, V L -A, V H -B and V L -B, wherein V H -A and V L -A are V H and V L domains of an antibody specific for antigen A, respectively, and V H -B and V L -B are V H and V L domains of an antibody specific for antigen B, respectively; V H -A is linked to V L -B by peptide linker 1, V L -B is linked to V H -B by peptide linker 2, V H -B is linked to V L -A by peptide linker 3; and said peptide linker 1 and said peptide linker 3 are a peptide bond or have about 1 to about 10 amino acids; and said peptide linker 2 has 3 to about 10 amino acids.