Polyinosinic Polycytidylic acid sodium salt is widely used in immunology and virology research as a potent synthetic double-stranded RNA (dsRNA) analog. It is commonly employed to stimulate the innate immune system by mimicking viral RNA, thereby activating pattern recognition receptors such as Toll-like receptor 3 (TLR3) and retinoic acid-inducible gene I (RIG-I). This activation triggers the production of interferons and other cytokines, making it a valuable tool for studying antiviral responses and immune modulation. Additionally, it is utilized in vaccine development to enhance immune responses and in cancer research to investigate its potential as an immunostimulant in immunotherapy. Its ability to induce apoptosis in certain cell types also makes it relevant in studies on cell death mechanisms.