Engineering Lymphatic Vessels and Lymphoid Microenvironments In Vitro to Investigate Immune Cell Trafficking

The lymphatic system is central to immune surveillance, coordinating antigen transport, and immune cell trafficking. While in vivo studies have revealed key aspects of lymphatic and lymph node biology, their complexity has motivated the development of in vitro platforms that enable controlled interrogation of specific immune processes. This review presents a tiered framework for organizing engineered lymphatic and lymph node models based on increasing architectural and functional complexity. Tier 1 models employ two-dimensional lymphatic endothelial monolayers to investigate immune cell docking, chemokine presentation, and junctional regulation. Tier 2 systems incorporate three-dimensional matrices and stromal organization to recreate lymphoid microenvironments, including lymph node scaffolds and immune organoids that support lymphocyte positioning and antigen handling under static conditions. Tier 3 platforms integrate microfluidic perfusion and compartmentalization to model lymphatic transport, flow-dependent endothelial behavior, and immune trafficking in dynamic lymphatic systems. Collectively, these models define the experimental landscape of in vitro lymphatic immunity.