Activated macrophages restrict invasive bacterial infection in a human intestinal organoid co-culture model

Here, we established a human colon organoid-derived monolayer co-culture system with macrophage-like THP-1 cells positioned directly beneath the epithelial layer. The model enabled controlled apical infection with Listeria monocytogenes and Salmonella Typhimurium while preserving epithelial barrier integrity.

PMA-differentiated THP-1 cells reduced intracellular L. monocytogenes burden, whereas additional activation with IFN-γ and LPS resulted in a pronounced reduction of both L. monocytogenes and S. Typhimurium, accompanied by decreased infection-associated cytotoxicity. Bulk RNA sequencing revealed a distinct co-culture transcriptional signature characterized by coordinated changes in inflammatory, antimicrobial, and epithelial lineage-associated programs.