The preparation of VEGFR1/CD3 bispecific antibody and its specific cytotoxicity against VEGFR1-positive breast cancer cells.

Bispecific antibody (BsAb) has been proved to be a very effective antitumor approach because of its distinctive advantages of immune-mediated cytotoxicity. To enhance the ability to recruit and activate T lymphocytes for tumor-specific killing, we constructed and prepared a recombinant human single-chain Fv bispecific antibody (BsAb), named VEGFR1/CD3 BsAb, targeting VEGFR1 and CD3. The VEGFR1/CD3 BsAb was expressed in CHO-K1 cells and purified by Ni-NTA affinity chromatography. The CD3 and VEGFR1-binding activity of VEGFR1/CD3 BsAb was confirmed by flow cytometry. T lymphocyte activation and proliferation induced by VEGFR1/CD3 BsAb were also demonstrated in vitro. Notably, our VEGFR1/CD3 BsAb presented a powerful and specific killing effect against VEGFR1-positive human breast cancer cell MDA-MB-231 and MDA-MB-435 through activating T lymphocyte at very low concentrations, indicating that it will be a valuable antibody drug for treatment of VEGFR1-positive cancers in the future.