[Specific targeting cytotoxicity to resistant leukemia cells mediated by anti-Pgp/anti-CD3 diabody].

Objective: To study the specific targeting cytotoxicity to drug-resistant leukemia cells mediated by anti-Pgp/anti-CD3 diabody.

Methods: The diabody was purified by affinity chromatography and identified by SDS-PAGE and FACS. The effect of the anti-Pgp/anti-CD3 diabody mediated lysis of Pgp-expressing tumor cells was assayed by human leukemia nude mice xenograft model in vivo.

Results: The diabody was produced in E.coli in a soluble functional form and could bind both Jurkat cells (CD3(+)) and K562/A02 cells (Pgp(+)). The binding rates were 86.25% and 86.26%, respectively. It could inhibit tumor growth by 98.57% and prolonged the survival of mice bearing xenografted K562/A02 cells.

Conclusion: The diabody was proved to be a potent agent for mediating T lymphocyte cytotoxicity to lyse Pgp expressing tumor cells in vitro and in vivo.