Abstract 2628: Generation of multi-antigen specific T cells for ovarian cancer using Prussian Blue nanoparticles and photothermal therapy

Abstract The immunosuppressive nature of ovarian cancer (OC) allows these tumors to evade the immune system, contributing to late-stage diagnoses and poor clinical outcomes for patients. However, a higher number of tumor-infiltrating lymphocytes is associated with improved clinical outcomes in OC. One type of lymphocyte, the T cell, can traffic to the tumor and kill tumor cells. We have shown that treating tumor cells with Prussian Blue nanoparticles and photothermal therapy (PBNP-PTT) results in immunogenic cell death, a form of cell death that is visible to the immune system, including T cells. PBNP-PTT-treated tumor cells were then used to expand tumor-specific T cells from partially genetically matched healthy donors against breast and brain cancer cell lines. These expanded T cells were better able to recognize and kill the target tumor cell lines than bulk unexpanded T cells from the same donors. Hence, we hypothesized that using PBNP-PTT-treated OC cells would allow us to expand a polyclonal tumor-specific T cell product that is cytolytic against OC cells in vitro and in vivo. We first evaluated whether multi-antigen OC-specific T cells could be expanded from partially genetically matched healthy donors and confirmed that PBNP-PTT elicited immunogenic cell death in the HLA-A*02: 01 human OC cell lines Hey and TykNu. Using our established in vitro T cell expansion protocol, we then successfully expanded T cells from multiple HLA-A*02: 01 healthy donors (n=3) against these cell lines. Functional analyses—including interferon-gamma ELISPOT, multi-color flow cytometry, and cytotoxicity assays—demonstrated that the expanded T cells had enhanced anti-tumor responses against OC cell lines compared to bulk unexpanded T cells derived from the same donors. Current work is expanding this approach to a syngeneic murine setting in C57BL/6J mice. Moreover, we will evaluate HLA-matched T cells and tumor cells from patients with OC ex vivo. Collectively, these efforts serve as a novel approach towards a curative immunotherapy for OC. Citation Format: Erin E. Grundy, Abigail Lee, Samantha Chin, Melissa Hadley, Danielle Schmidt, Loretta Wang, Olivia Cox, Khadra Omar, Catherine M. Bollard, Rohan Fernandes, Katherine B. Chiappinelli. Generation of multi-antigen specific T cells for ovarian cancer using Prussian Blue nanoparticles and photothermal therapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 2628.