Construction of Anti-HER2 Recombinants as Targeting Modules for a Drug-delivery System Against HER2-positive Cells

Background/Aim: Recombinant antibodies have been investigated and used in applications such as targeting modules of drug-delivery systems (DDS) against cancers. This study aimed to prepare recombinant antibodies against HER2, containing sortase A (SrtA) recognition sequence, that are applicable as targeting modules in DDS after linkage with the drug-carrier containing oligoglycine-acceptor peptide by SrtA transpeptidation. Materials and Methods: The recombinant trastuzumab fragment antibodies (scFvs and Fab) with the SrtA-recognition motif (LPXTG) at their C-terminal were constructed and expressed in Escherichia coli and Chinese hamster ovary (CHO) cells, respectively. The reactivity of the purified recombinant antibodies towards HER2-expressing cells was also evaluated via immunofluorescent staining. Results: Fab demonstrated higher yield and purity and better reactivity towards HER2-expressing cells (HCT-15 and HeLa) when compared to scFvs. Conclusion: The CHO expression system possesses superior yield and purity when compared to the E. coli expression system with respect to the preparation of recombinant antibodies applicable in targeting modules for DDS (DDS-TM). Moreover, a Fab variant prepared in this study demonstrated the potential to be a DDS-TM against HER2-expressing cancer cells.