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 S mu as a binding domain was accurate and efficient, producing trans-spliced mRNA of up to 2% of cis-spliced one. Since S mu 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). (C) Elsevier Inc. All rights reserved.