Cynomolgus Monkey (Macaca fascicularis) Interleukin-1 Beta (IL-1β) is a potent pro-inflammatory cytokine produced primarily by activated macrophages, monocytes, and dendritic cells in response to infection, tissue injury, or inflammatory stimuli. Synthesized as an inactive precursor (pro–IL-1β), it is cleaved into its active form by caspase-1 within inflammasome complexes—most notably the NLRP3 inflammasome—and signals through the IL-1 receptor type 1 (IL-1R1), activating NF-κB and MAPK pathways that drive fever, leukocyte recruitment, endothelial activation, and acute-phase responses. Highly homologous to human IL-1β, cynomolgus IL-1β plays a central role in nonhuman primate models of infectious diseases such as dengue, influenza, SARS-CoV-2, tuberculosis, and bacterial sepsis, where its expression correlates with systemic inflammation and disease severity. It is also relevant in models of autoimmune disease, vaccine-induced immune activation, and immunotoxicology studies. Because cynomolgus monkeys are widely used in preclinical safety assessment and translational biomedical research, characterization of IL-1β is essential for evaluating inflammasome activation, cytokine release syndromes, and therapeutic modulation of inflammatory pathways, bridging mechanistic insights between nonhuman primate models and human inflammatory disease.