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 V H–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).