Patent ID: 7018809
Filing Date: 2006-03-28
Classification: C07K,Y10S

Abstract:
1. A method for the production of a Fab′ antibody fragment coupled to a heterologous molecule, comprising the steps of: (a) expressing nucleic acid encoding a Fab′ antibody fragment in a prokaryotic host cell culture comprising the nucleic acid such that the Fab′ is secreted to a periplasmic space of a prokaryotic host cell; (b) recovering the Fab′ from the host cell culture, wherein the recovered Fab′ comprises a CH1 fused to the amino acid sequence of CysXX, wherein X is Ala, Arg, Asp, or Pro, and wherein the cysteine of Cys XX is present as a free thiol, and the amount of the Fab′ recovered from the host cell culture exceeds the amount of F(ab′) (c) coupling the cysteine of CysXX that is present as a free thiol of the recovered Fab′ to a heterologous molecule.