A Comparative Investigation of the Bispecific Antibody: Expression in Expi293F Cells and E.Coli

Aims: Bispecific antibodies are capable of targeting two cell surface markers simultaneously. Blinatumomab an anti-CD3/CD19 Bispecific T cell engager antibody (BiTE) is approved for clinical application by FDA. This BiTE effectively targets malignant cells in ALL (Acute Lymphoblastic Leukemia) patients. For production of large quantities of such antibodies in industrial settings choice of host cells for antibody production is critical. Mammalian cells and E.Coli strains are the most prominent hosts for production of antibodies and antibody fragments, respectively. Methods & Materials: In our study for protein production in mammalian system pcDNA3.1 (+) was used for subcloning of a gene expression cassette encoding our BiTE antibody and pET22b backbone was used for bispecific antibody expression in E.Coli. The produced BiTE in both experiments was purified using Ni-NTA columns followed by SDS-PAGE and western blot analysis, and binding capability of the secreted and purified antibodies was measured by ELISA. Findings & Conclusion: This comparison showed better binding capability indices when mammalian expression was used in comparison to expression of the exact same protein in E.Coli.