Patent ID: 7429652

Claim:
A recombinant polynucleotide comprising a coding sequence that encodes a light (L) chain polypeptide of a non-single-chain antigen-binding unit, wherein the non-single-chain antigen-binding unit comprises: (a) the encoded light (L) chain polypeptide having a light (L) chain variable region fused in-frame to a first heterodimerization polypeptide and (b) a heavy (H) chain polypeptide having a heavy (H) chain variable region fused in-frame to a second heterodimerization polypeptide wherein the L chain and the H chain polypeptides dimerize via pairwise affinity of the first and second heterodimerization polypeptides, said first and second heterodimerization polypeptides comprising heterodimeric receptor polypeptides that mediate heterodimerization.