CSF1 (Colony-Stimulating Factor 1), also known as macrophage colony-stimulating factor (M-CSF), is a cytokine critical for the survival, proliferation, and differentiation of monocytes and macrophages. It binds to its receptor CSF1R (CD115), activating signaling pathways that regulate immune cell function, tissue homeostasis, and developmental processes. Dysregulation of the CSF1/CSF1R axis is implicated in diseases like cancer, inflammatory disorders, and osteoporosis.
CSF1 antibodies are immunologic tools designed to target either CSF1 or CSF1R. These antibodies (often monoclonal) are used to block ligand-receptor interactions, thereby modulating macrophage activity. In research, they help elucidate the role of CSF1-dependent macrophages in tumor microenvironments, where tumor-associated macrophages (TAMs) promote angiogenesis, immunosuppression, and metastasis. Therapeutically, anti-CSF1/CSF1R antibodies are explored as potential treatments to deplete TAMs or inhibit pro-tumorigenic signaling in cancers.
Preclinical studies highlight their efficacy in reducing tumor growth and synergizing with chemotherapy or immunotherapy. However, challenges like compensatory cytokine pathways and off-target effects necessitate further optimization. Overall, CSF1 antibodies represent a promising strategy to target macrophage-driven pathologies, with ongoing clinical trials evaluating their safety and therapeutic potential.