Advanced Human Immune Cell-Organoid Co-Cultures for Functional Testing of Cancer Nanovaccines.

Pancreatic ductal adenocarcinoma (PDAC) remains a major clinical challenge due to late detection and limited treatment responsiveness. To better evaluate complex immunotherapies in a human-relevant setting, we developed an integrated organoid-immune co-culture pipeline using PDAC patient-derived organoids (PDOs) and matched HLA immune cells. As a proof of concept, we assessed an MSLN-targeted nanovaccine (Mesovac), alone and in combination with FOLFIRINOX chemotherapy and Atezolizumab. We evaluated Mesovac across a multi-stage pipeline, including T-cell stimulation, ex vivo expansion, and PDO-immune co-cultures, to assess immune activation, specificity, and synergy with combinatorial treatments. MSLN-stimulated T-cells, derived from PDAC patients, showed increased IFN-γ production and selective infiltration into MSLN-expressing PDOs. Artificial antigen-presenting cells (aAPCs) boosted the expansion of reactive T-cells, enhancing antitumor responses. Notably, combining Mesovac with FOLFIRINOX and Atezolizumab maintained PD-L1+ T-cell levels and reduced cancer stem cells and aggressive PDAC subsets. Using this advanced in vitro workflow, we highlight that this platform, using human organoid-immune cell co-cultures, enables the evaluation of complex processes related to nanovaccine strategies that would not be possible in vivo.