Trans-splicing as a novel method to rapidly produce antibody fusion proteins

To cultivate the use of trans-splicing as a novel means to rapidly express various antibody fusion proteins, we tried to express antibody–reporter enzyme fusions in a COS-1 co-transfection model. When a vector designed to induce trans-splicing with IgH pre-mRNA was co-transfected with a vector encoding the mouse IgM locus, the expression of VH–secreted human placental alkaline phosphatase (SEAP) as well as Fab–SEAP were successfully expressed both in mRNA and protein levels. Especially, the vectors encoding complementary sequence to Sμ as a binding domain was accurate and efficient, producing trans-spliced mRNA of up to 2% of cis-spliced one. Since Sμ sequence should exist in every IgH pre-mRNA, our finding will lead to the rapid production and analysis of various antibody–enzyme fusions suitable for enzyme-linked immunosorbent assay (ELISA) or antibody-dependent enzyme prodrug therapy (ADEPT).