Targeting immunotherapy for bladder cancer using anti‐CD3× B7‐H3 bispecific antibody

OBJECTIVE: B7‐H3 is attractive for cancer immunotherapy with B7‐H3 overexpressed tumors. To explore whether B7‐H3 is an effective target for patients with bladder cancer, anti‐CD3× anti‐B7‐H3 bispecific antibodies (B7‐H3Bi‐Ab) was armed with activated T cells (ATC) to kill bladder cancer cells. METHODS: High expressions of B7‐H3 on human bladder cancer cells were detected, including Pumc‐91 and T24 cells, and their chemotherapeutic drug‐resistant counterparts. ATC generated from healthy donors were stimulated with anti‐CD3 monoclonal antibody and interleukin‐2 (IL‐2) for 13 days. The ability of ATC armed with B7‐H3Bi‐Ab to kill bladder cancer cells was detected by flow cytometry, LDH, Elisa, and luciferase quantitative assay. Moreover, ATC generated from bladder cancer patients was armed with B7‐H3Bi‐Ab to verity the cell killing by the methods as previously described. RESULTS: Compared with unarmed ATC, a significant increased cytotoxicity of B7‐H3Bi‐Ab‐armed ATC against bladder cancer cells was discovered. The B7‐H3Bi‐Ab‐armed ATC secreted more IFN‐γ, TNF‐α, and expressed high levels of activation marker CD69. Interestingly, despite the presence of immunosuppression in patients and resistance in chemotherapeutic drug‐resistant cancer cell lines, B7‐H3Bi‐Ab‐armed ATC from patients with bladder cancer still showed significant cytotoxic activity against bladder cancer cells and their chemotherapeutic drug‐resistant counterparts. CONCLUSION: B7‐H3 is an effective target for bladder cancer. B7‐H3Bi‐Ab enhances the ability of ATC to kill bladder cancer cells. B7‐H3Bi‐Ab‐armed ATC is promisingly to provide a novel strategy for current bladder cancer therapy.