A. PDAC patient information corresponding to PDO and CAF co-cultures. B. Schematic of mesoFAP CAR T-cells targeting organoid co-cultures consisting of PDAC PDO and CAF. C. Co-culture transillumination at day 2 and day 5 of co-culture visualized by Nikon ECLIPSE Ti2 microscope at 20X. Transillumination and RPF images merged by NIS-Elements AR Software. D. CD3+ recovery acquired at both day 2 and day 5. E. Representative flow cytometry plots of specific cytotoxicity of mesoFAP targeting JHH317 FAP+ CAF and PDO co-culture at day 5. F. Flow cytometric analysis showing PDO count recovered on day 2 and day 5. G. Flow cytometric analysis showing CAF count recovered on day 2 and day 5. H. Flow cytometric analysis of activation and exhaustion markers on CD3+ CART-cells at day 2 and day 5. I. VITAL CTL killing assay of target PDO with CAR T effector cells, and UTD T-cells in increasing ratios of effector : target/T cells (technical duplicate; unpaired, two-tailed t-test, p=0.09 at 10:1:1 ratio). Data represent means of biological and technical triplicates. Stars indicate significance as determined by Wilcoxon test (panels D, F, and G) or paired, two-tailed t-test (panel H and I). *p <0.05, ****p <0.0001. PDO: pancreatic ductal adenocarcinoma organoids, Dx: diagnosis, NGS: next-generation sequencing. Schematics were created with BioRender.com.