Human Interleukin 34 (IL34) Protein

Background

Interleukin 34 (IL34) is a pro-inflammatory cytokine identified in 2008 through bioinformatics analysis of the human genome. Unlike most interleukins, which were discovered through their immunological properties, IL-34 was initially identified for its role as a ligand for the colony-stimulating factor-1 receptor (CSF1R), a receptor known to regulate the survival, proliferation, and differentiation of macrophages and monocytes. IL-34 functions in synergy with macrophage colony-stimulating factor (M-CSF or CSF1), which is another ligand for CSF1R, to regulate immune system homeostasis. IL-34 is secreted by several cell types, including fibroblasts, keratinocytes, neuronal cells, and epithelial cells, and is expressed across different tissues, particularly in the spleen, brain, and kidneys. The broad tissue distribution of IL-34 underscores its involvement in immune modulation in diverse physiological contexts, including neuroinflammation, autoimmune diseases, and cancer. Its role is central to macrophage biology, impacting innate immune responses, tissue repair, and inflammatory processes.