(E)-C-HDMAPP (ammonium salt) is primarily utilized in the field of immunology and cancer research. It serves as a key intermediate in the biosynthesis of isoprenoids, which are crucial for the post-translational modification of proteins involved in cell signaling and immune responses. This compound is particularly significant in the study of Vγ9Vδ2 T cells, a subset of gamma delta T cells that play a role in the immune system's defense against infections and tumors. Researchers use (E)-C-HDMAPP to activate these T cells, enabling the study of their mechanisms and potential therapeutic applications in cancer immunotherapy. Additionally, it is employed in the development of novel immunotherapies aimed at enhancing the body's natural ability to recognize and destroy cancer cells. Its role in modulating immune responses also makes it a valuable tool in vaccine development and autoimmune disease research.