Abstract 4230: Modeling the cDC1 ex vivo and in vitro: Development and comparison of a conventional dendritic cell culture system for industry

Abstract Conventional dendritic cells (cDC) are innate immune cells specialized in antigen sampling and subsequent cross-presentation to immune cells and are critical for an effective anti-tumor immune response. While crucial to immunity against intracellular pathogens, viruses, and tumors, cDC type I (cDC1) are a relatively rare population and constitute about 0.05% of cells in the blood. Using these rare cells in screening assays can be a challenge, as very small proportions are found in peripheral human blood and since they are difficult to isolate with high viability and purity. Existing methods to generate acceptable numbers of cDC1s require a feeder cell line, which is not accessible to many laboratories. Using a systematic approach, we developed a scalable differentiation system to generate a mixed culture containing cDC1 cells from CD34+ hematopoietic stem cells isolated from cord blood that does not require feeder cells. This culture of cells has been phenotypically and functionally characterized to express high levels of CD141 and Clec9a, as well as responsiveness to various activating stimuli including poly (I:C). Cells derived from this culture method express similar levels of CD141 and Clec9a compared to those observed in peripheral blood of healthy donors. Our effort to find a less laborious, more efficient system includes comparison to cDC1 responses from an in vitro differentiation system to cDC1s isolated from humanized mouse bone marrow, with evaluation of both surface marker phenotype and responsiveness to activating stimuli. We also compared the responses of these cells to monocyte derived dendritic cells that express CD141 and Clec9a. These data demonstrate that the HSC-derived cDC1 cultures provide a comparison of unique dendritic cells that may be utilized for screening assays in an industry setting. Citation Format: Laura L. Goodfield, Johanna Lahdenranta, Heather Scott, Tamera Ashworth, Lia Luus, Anna F. Licht, Kevin McDonnell, Phil Brandish, Nicholas Keen. Modeling the cDC1 ex vivo and in vitro: Development and comparison of a conventional dendritic cell culture system for industry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4230.