Figure 1.

Schematic representation of the CE2, sCE2 and C28-sCE2 expression cassette. The CE2 cDNA is inserted as an EcoRI fragment into pcDNA3. The encoded protein contains its wildtype N-terminal signal peptide and a C-terminal cellular retention signal sequence HTEL. The structural elements of pSTCF include the strong cytomegalovirus (CMV) promoter, IgG kappa leader sequence, and a C-terminal myc- and His-tag (mycHis) for easy detection and purification. sCE2, without retention signal, is inserted as a SfiI/NotI fragment into pSTCF. The anti-EpCAM scFv C28 is inserted as a SfiI/NotI fragment. The gene encoding CE2 is inserted as a NotI/NotI fragment, after the (Gly₄Ser)₂ linker is inserted in the NotI and ApaI restriction sites.