Bispecific T cell engagers and their synergistic tumor immunotherapy with oncolytic viruses.

Tumor immunotherapy, especially T cell based therapy, is becoming the main force in clinical tumor therapies. Bispecific T cell engager (BiTE) uses the single chain variable fragments (scFv) of two antibodies to redirect T cells to kill target cells. BiTEs for hematologic tumors has been approved for clinical use, and BiTEs for solid tumors showed therapeutic effects in clinical trials. Oncolytic viruses (OVs) of the adenovirus expressing p53 and herpes simplex virus expressing GM-CSF was approved for clinical use in 2003 and 2015, respectively, while other OVs showed therapeutic effects in clinical trials. However, BiTE and Oncolytic virus (OV) have their own limitations. We propose that OV-BiTE has a synergistic effect on tumor immunotherapy. Feng Yu designed the first OV-BiTE in 2014, which remarkably eradicated tumors in mice. Here we review the latest development of the structure, function, preclinical studies and/or clinical trials of BiTE and OV-BiTE and provide perspective views for optimizing the design of OV-BiTE. There is no doubt that OV-BiTE is becoming an exciting new platform for tumor immunotherapy and will enter clinical trial soon. Exploring the therapeutic effects and safety of OV-BiTE for synergistic tumor immunotherapy will bring new hope to tumor patients.