A VEGFR2-MICA bispecific antibody activates tumor-infiltrating lymphocytes and exhibits potent anti-tumor efficacy in mice

MHC class I-related chain A (MICA) is one of the major ligands for natural killer group 2 member D (NKG2D), which is an activating NK receptor. MICA is expressed on the surface of human epithelial tumor cells, and its shedding from tumor cells leads to immunosuppression. To activate immune response in the tumor microenvironment, we designed an anti-VEGFR2-MICA bispecific antibody (JZC01), consisting of MICA and an anti-VEGFR2 single chain antibody fragment (JZC00) and explored its potential anti-tumor activity. JZC01 targeted vascular endothelial growth factor receptor 2 (VEGFR2) and inhibited tumorigenesis by blocking the VEGFR2 signaling pathway. Additionally, JZC01 promoted NK and CD8(+) T cells to release IFN-gamma and engaged activated lymphocytes to lysis of VEGFR2-expressing tumor cells. The in vivo anti-tumor activity of JZC01 was investigated by establishing a Lewis lung cancer cell-transplanted mouse model. It effectively reduced the tumor vascular density and increased the infiltration and activation of NK and CD8(+) T cells in the tumor microenvironment. Thus, JZC01 functions in anti-tumor angiogenesis and anti-tumor immune activation, and showed improved anti-tumor efficacy combined with docetaxel, which provides a new insight into anti-tumor therapy.