Improved Expression of Single-Chain Fragment Variable Antibodies Devoid of Leader Peptides in the Cytoplasm

Single-chain variable fragment (scFv) are commonly expressed and translocated into the periplasmic layer with the aid of a leader peptide. This process allows for proper protein folding with the formation of disulfide bonds. The natural oxidative environment of the periplasm promotes disulfide bond formation compared to the highly reductive environment of the cytoplasm. Thus, a leader peptide is vital for the translocation process with different leader peptides being reported. However this method usually results in lower yields and often incomplete translocation of scFv. In this study, we compared the expression of two scFvs using different cell types without a leader peptide based on yield and functionality. We found that scFv expression without leader peptides in the cytoplasm using SHuffle® T7 Escherichia coli K-12 strain resulted in highest expression yields with preserved functionality. The SHuffle® T7 host is a suitable alternative for high-yield production of functional scFv devoid of leader peptides.