Vascular endothelial growth factor-A (VEGF) is the dominant angiogenic factor that promotes tumor neovascularization, making it a critical target for cancer therapy. VEGF binds and activates VEGF receptor 1 (VEGFR1) and VEGFR2, with VEGFR2 being the principal receptor mediating VEGF-induced angiogenesis while VEGFR1 has a negative regulatory effect on this process. Previously, we found that selective inhibition of VEGF binding to VEGFR2 with a fully human monoclonal antibody (r84) or its mouse chimeric counterpart (mcr84) is sufficient for effective control of tumor growth in preclinical models of breast cancer. However, accumulating evidence indicates that the effect of blocking VEGF activity in solid tumors extends beyond inhibition of angiogenesis. Concordantly, we have shown that VEGF blockade regulates immune cell trafficking across the endothelium by increasing the expression of adhesion molecules while decreasing FasL expression on tumor vasculature. In addition, specifically blocking VEGF binding to VEGFR2 promotes an immune stimulatory microenvironment by enhancing activation of CD8+ cytotoxic T cells as evidenced by elevated secretion of Granzyme B and IFN-γ. In addition, VEGF blockade also reduces FoxP3+ regulatory T cell infiltration in multiple murine models of cancer. We and others have shown that immune cells express receptors for VEGF. Our data indicate that VEGFR2 expression is elevated on myeloid cells selectively in tumor-bearing animals. Consistent with VEGFR2 expression, treatment with mcr84 results in a reduction in macrophage/myeloid cell infiltration into murine breast tumors. In conclusion, our results enhance understanding of the function of VEGFR2 signaling on myeloid cells and suggest that selective inhibition of VEGF from binding VEGFR2 facilitates immune activation landscape in breast cancer models, which might enhance the efficacy of immune checkpoint blockade. This abstract is also being presented as PO045. Citation Format: Yuqing Zhang, Huocong Huang, Noah Sorrelle, Rolf Brekken. Selective inhibition of VEGF binding to VEGFR2 promotes an immune stimulatory microenvironment in murine models of breast cancer [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2020 Oct 19-20. Philadelphia (PA): AACR; Cancer Immunol Res 2021;9(2 Suppl):Abstract nr PR011.