# Advanced Human Immune Cell‐Organoid Co‐Cultures for Functional Testing of Cancer Nanovaccines

## TL;DR

Researchers developed a human-like lab system using patient organoids and immune cells to test cancer nanovaccines and their combinations with chemotherapy and immunotherapy.

## Contribution

The novel contribution is an integrated organoid–immune co-culture pipeline for evaluating cancer nanovaccine efficacy and synergy in a human-relevant model.

## Key findings

- MSLN-stimulated T-cells showed increased IFN-γ production and selective infiltration into MSLN-expressing organoids.
- Combining Mesovac with FOLFIRINOX and Atezolizumab reduced cancer stem cells and aggressive PDAC subsets while maintaining immune activity.
- Artificial antigen-presenting cells enhanced T-cell expansion and antitumor responses in co-culture systems.

## Abstract

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.

Pancreatic ductal adenocarcinoma remains difficult to treat. We establish an organoid–immune co‐culture using patient‐derived organoids and matched T‐cells to assess cancer vaccines. A mesothelin‐targeted nanovaccine activates antigen‐specific T‐cells, increases IFN‐γ, and targets MSLN+ organoids. Combined with FOLFIRINOX and Atezolizumab, it reduces stemness and maintains immune activity, enabling personalized ex vivo vaccine evaluation.