Cynomolgus monkey IL-17A (Interleukin-17A) is a pro-inflammatory cytokine belonging to the IL-17 family that plays a central role in host defense and immune-mediated inflammation in Cynomolgus monkeys (Macaca fascicularis). The IL-17A protein is highly conserved among non-human primates and is functionally comparable to that of Rhesus monkey (Macaca mulatta) and humans, supporting its relevance in translational research. IL-17A is produced primarily by Th17 CD4⁺ T cells, as well as by γδ T cells and innate lymphoid cells, in response to microbial infection and inflammatory stimulation. It acts on epithelial, endothelial, and stromal cells to induce expression of pro-inflammatory cytokines (e.g., IL-6, TNF-α), chemokines (such as CXCL8), and antimicrobial peptides, thereby promoting neutrophil recruitment and enhancing mucosal immunity. In healthy Cynomolgus monkeys, basal IL-17A levels are typically low, but concentrations increase during bacterial or fungal infection, inflammatory challenge, or immune activation. In preclinical and translational research, Cynomolgus monkey IL-17A is particularly relevant in models of autoimmune disease, inflammatory disorders, vaccine immunogenicity, and evaluation of biologics targeting the IL-17 pathway, providing insight into Th17-mediated immune responses and neutrophilic inflammation in non-human primate systems.