Matrix viscoelasticity regulates dendritic cell migration and immune priming

Abstract The tumor microenvironment shapes immune surveillance through its mechanical properties, yet the role of matrix viscoelasticity remains unclear. Here, we used a collagen system with tunable viscoelasticity to define how matrix relaxation directs dendritic cell (DC) behavior. Elastic matrices impaired DC migration by limiting actomyosin-driven collagen remodeling, thereby reducing DC-T cell encounters and weakening T cell priming, activation, proliferation, and tumor killing. Blocking DC migration in fast-relaxing gels recapitulated key aspects of the impaired T cell priming seen in elastic matrices. Prolonged confinement in elastic extracellular matrix induced a mechanomemory state, locking DCs into reduced motility even after transfer to viscoelastic environments, corresponding to altered chromatin accessibility. Finally, studies with patient-derived ependymoma samples confirmed these findings, identifying viscoelasticity as a barrier to antitumor immunity with implications for therapeutic intervention.