Abstract 693: A novel multi-subset dendritic cell vaccine derived from hematopoietic progenitor cells

Abstract Owing to their molecular features, tissue localization and antigen processing and presentation capacity, dendritic cells (DCs) induce and regulate T cell immunity including licensing T cells to kill target cells. However, tumors often suppress DC differentiation and function leaving cancer patients with DC populations that are quantitatively and qualitatively deficient. This limits both the native immune responses to tumors as well as response to cancer therapy including immunotherapy. Thus, provision of healthy and functionally intact DCs to replace and correct the in vivo function offers an interesting therapeutic opportunity. DCs are composed of multiple subsets which specialize in activation of different immune effectors. Thus, a combination of DC subsets could generate a broad and diverse immunity targeted at cancer. To date, several attempts have been made to generate functional human DCs ex vivo for injection to patients, but the DC subtypes most effective in generation of anti-tumor responses—cDC1 and cDC2s—have proven difficult to make ex vivo using clinically compliant protocols. Here we show that cDC1s and cDC2s can be generated at high yield from hematopoietic progenitor cells (HPCs) from three different HPCs sources (including adult bone marrow) using clinically compliant protocols. We characterize the phenotype and functionality of these cells showing that both cDC1s and cDC2s efficiently process antigens, stimulate, and expand T cells specific for those antigens, and that those T cell populations display targeted killing of tumor cells in vitro. The ability to produce these subtypes using clinically compliant protocols is a major step towards developing effective autologous DC therapy for cancer patients. Citation Format: Chun Yu, Richard L. Barrett, Ananya Zutshi, Karolina Palucka. A novel multi-subset dendritic cell vaccine derived from hematopoietic progenitor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 693.