Expression of recombinant anti-breast cancer immunotherapeutic monoclonal antibody in baculovirus-insect cell system.

The anti-breast cancer monoclonal antibody (m Ab) BR55 was expressed in the baculovirus-insect cell expression system, which is advantageous because of its high production capacity, cell culture flexibility and glycosylation capability. The baculovirus-insect cell expression system was successfully established for production of m Ab BR55 and m Ab BR55 fused with the KDEL ( Lys- Asp- Glu- Leu) endoplasmic reticulum ( ER) retention signal (m Ab BR55K). The heavy chain ( HC) and light chain ( LC) genes of m Ab BR55 were cloned under the control of the polyhedrin ( PPH) and P10 promoters, respectively, in the p Fast Bac Dual vector. The antibody gene-expression cassettes carrying both the HC and LC genes were transferred into a bacmid in Escherichia coli ( DH10Bac). The bacmid carrying the expression cassettes was transfected into Sf 9 insect cells to generate baculovirus expressing m Ab BR55 and BR55K. Western blot analysis confirmed the expression of m Ab BR55 and BR55K in baculovirus-infected insect cells. Cell direct enzyme linked immunosorbent assay ( ELISA) showed that both m Abs from insect cell lysates or cell culture medium bound to MCF-7 human breast cancer cells. Both m Ab BR55 and BR55K were successfully purified using a Protein A affinity column. Collectively, these results suggest that the anti-breast cancer m Ab BR55 can be expressed, properly assembled and purified from the baculovirus expression system, which can serve as an alternative system for antibody production. [ABSTRACT FROM AUTHOR]