Development of a personalized dendritic cell vaccine and single-cell RNA sequencing-guided assessment of its cell type composition

Background aims: Dendritic cell (DC)-based immunotherapy is a promising approach to treat cancer; how-ever, there is no consensus on the manufacturing processes. Cell type heterogeneity in products manufac-tured by various methods is understudied and may elicit safety concerns from the regulatory perspective.Methods: We characterized the cell type composition of a recently developed DC vaccine, CUD-002, consist-ing of DCs loaded with mRNA encoding personalized tumor neoantigens (NCT05270720).Results: Using single-cell transcriptomic analysis as an unbiased approach, we found that >80% cells in the final product were DCs and the rest primarily comprised myelocytes and lymphocytes. Subsequent fluores-cence-activated cell sorting analyses confirmed these cellular identities. These results indicate that unin-tended cells originate from leukapheresis, the first step of the manufacturing process, and thus likely safe. Consistently, no overt toxicity or tumorigenicity was observed in mice inoculated with CUD-002.Conclusions: Considering that leukapheresis is a widely used procedure for collecting diverse peripheral blood cell types to manufacture various cytotherapies, this study establishes a workflow to analyze and address regulatory considerations on cell type heterogeneity.(c) 2022 International Society for Cell & Gene Therapy. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)