Purity >95% as determined by SDS-PAGE. Interleukin 17AF (IL-17AF) is a heterodimer that is composed of the interleukin 17A (IL-17A) and interleukin 17F (IL-17F) members of the IL-17 family of cytokines. IL-17AF is produced by T helper 17 cells (Th17) following interleukin 23 (IL-23) stimulation. IL-17AF signals through the IL-17RA/IL-17RC receptor complex and functions to regulate inflammatory responses. IL-17AF induces chemokine and airway neutrophilia production, similar in function to IL-17A and IL-17F homodimers. In regard to these functions, IL-17AF is less active than the IL-17A homodimer and shows greater activity than the IL-17F homodimer. Human and rat IL-17AF are active on mouse cells.