Modulating T Cell Activation Using Depth Sensing Topographic Cues.

This report examines how sensing of substrate topography can be used to modulate T cell activation, a key coordinating step in the adaptive immune response. Inspired by the native T cell-antigen presenting cell interface, micrometer scale pits with varying depth are fabricated into planar substrates. Primary CD4+ T cells extend actin-rich protrusions into the micropits. T cell activation, reflected in secretion of cytokines interleukin-2 and interferon gamma, is sensitive to the micropit depth. Surprisingly, arrays of micropits with 4 μm depth enhance activation compared to flat substrates but deeper micropits are less effective at increasing cell response, revealing a biphasic dependence in activation as a function of feature dimensions. Inhibition of cell contractility abrogates the enhanced activation associated with the micropits. In conclusion, this report demonstrates that the 3D, microscale topography can be used to enhance T cell activation, an ability that most directly can be used to improve production of these cells for immunotherapy.