Nucleoprotein 396-404 is primarily utilized in immunological research and vaccine development. It plays a critical role in studying immune responses, particularly in the context of viral infections. Researchers use it to identify and analyze epitopes, which are essential for designing peptide-based vaccines. Additionally, it serves as a tool in understanding T-cell responses, aiding in the development of immunotherapies for diseases like influenza and other viral infections. Its application extends to diagnostic assays, where it helps in detecting specific antibodies or immune cells, contributing to advancements in infectious disease management.