Harnessing Notch Signaling to Enhance the Generation and Functionality of Human Conventional Type 1 Dendritic Cells for Cancer Immunotherapy Applications.

A dendritic cell (DC)-based vaccine, Sipuleucel-T, remains the sole FDA-approved cancer vaccine. Despite their established safety and efficacy against cancers and infections in numerous trials, long-term clinical benefits have been modest. Most trials have employed DCs derived from blood monocytes, but emerging evidence underscores the unique role of conventional type 1 DCs (cDC1) in triggering potent antitumor immune responses and their intratumoral infiltration with favorable prognoses in many cancers. However, the scarcity of cDC1s in peripheral blood and the challenges in generating them in vitro have hindered a deeper understanding of their biology and their widespread application as cellular vaccines. In this study, we present a serum-free culture system capable of generating billions of human cDC1s from CD34+ progenitors derived from cord or peripheral blood. The system leverages the requirement of Notch signaling for cDC1 differentiation and generates DCs that closely resemble in vivo cDC1s, exhibiting functions including cellular antigen cross-presentation. This robust protocol enables the scalable production of cDC1s for both fundamental biological research and therapeutic applications.