Patent ID: 7709224

Claim:
A method for producing an immunoglobulin or a fragment of the immunoglobulin having antigen-binding activity, wherein the immunoglobulin fragment is selected from the group consisting of Fab, F(ab′) 2 , Fv(scFv) and Fv immunoglobulin fragments, comprising the steps of: (i) transducing a host cell with a vector comprising in the 5′ to 3′ direction, a cytomegalovirus enhancer/chicken beta-actin (CAG) promoter operably linked to all of (1) a coding sequence for a heavy chain of the immunoglobulin or a fragment of the heavy chain, (2) a coding sequence for a furin cleavage site, (3) a coding sequence for a 2A self-processing cleavage site and (4) a coding sequence for a light chain of the immunoglobulin or a fragment of the light chain; and (ii) expressing the heavy chain of the immunoglobulin or the fragment of the heavy chain and the light chain of the immunoglobulin or the fragment of the light chain in the transduced host cell, wherein the heavy chain of the immunoglobulin or the fragment of the heavy chain and the light chain of the immunoglobulin or the fragment of the light chain are expressed in an equimolar or close to equimolar ratio.