λ antibodies

A method of expressing a bispecific antibody comprising two heavy chains and a common light chain, the method comprising:

• providing a host cell comprising a nucleic acid encoding a polypeptide comprising an antibody light chain variable (VL) domain with an N-terminal signal peptide, wherein the VL domain comprises a sequence derived from a v λ gene segment and a sequence derived from a j gene segment, wherein the N-terminal signal peptide differs from the native N-terminal signal peptide for said v λ gene segment, and wherein the residue corresponding to IMGT position 1 of the VL domain is absent, wherein the host cell further comprises one or more nucleic acids encoding the two heavy chains,
• culturing said host cell under conditions for expression of the antibody heavy and light chains,
• wherein the N-terminal signal peptide is cleaved off the VL domain to provide an antibody light chain comprising a mature VL domain,
• wherein the N-terminal residue of the polypeptide comprising the mature VL domain is IMGT position 2 of the VL domain, and
• wherein the light chain domain assembles with each of the two heavy chains to provide said bispecific antibody.