Nanotopography-guided migration of T cells.

T cells navigate a wide variety of tissues and organs for immune surveillance and effector functions. Although nanoscale topographical structures of extracellular matrices and stromal/endothelial cell surfaces in local tissues may guide the migration of T cells, there has been little opportunity to study how nanoscale topographical features affect T cell migration. In this study, we systematically investigated mechanisms of nanotopography-guided migration of T cells using nanoscale ridge/groove surfaces. The velocity and directionality of T cells on these nanostructured surfaces were quantitatively assessed with and without confinement, which is a key property of three-dimensional interstitial tissue spaces for leukocyte motility. Depending on the confinement, T cells exhibited different mechanisms for nanotopography-guided migration. Without confinement, actin polymerization-driven leading edge protrusion was guided toward the direction of nanogrooves via integrin-mediated adhesion. In contrast, T cells under confinement appeared to migrate along the direction of nanogrooves purely by mechanical effects, and integrin-mediated adhesion was dispensable. Therefore, surface nanotopography may play a prominent role in generating migratory patterns for T cells. Because the majority of cells in periphery migrate along the topography of extracellular matrices with much lower motility than T cells, nanotopography-guided migration of T cells would be an important strategy to efficiently perform cell-mediated immune responses by increasing chances of encountering other cells within a given amount of time.