Multifunctional devices for the regulation of cytotoxic activity of natural killer cells

Innate immune system is based on natural killer (NK) cells, whose immune activity is regulated through a delicate balance among signals delivered by a multitude of activating and inhibitory receptors. However, the exact mechanism of how different receptors integrate their signals, and in particular how their signal integration depends on the receptor spatial organization, is unclear. Recently, biomimetic devices that control spatial organization of receptors within the cell membrane have been extensively used to study how the receptor spatial order regulates cell function, including that of immune lymphocytes. Yet, these devices have been limited to control only receptor of one type, and thus could not been used to study signal integration between different receptors. Here, we realized two types of biomimetic devices for the spatial control of inhibitory and activating receptors, whose signal integration is currently a subject of intensive study. The first type is based on photolithographically patterned lines of Ti and Au, orthogonally functionalized with activating and inhibitory ligands. Such devices spatially determine the micro-clustering of both receptors within the cells. The second type of devices is based on pairs of sub-10 nanodots of Au and Ti fabricated by nanoimprint lithography and selectively functionalized different ligands. Besides the used nanofabrication and functionalization approaches, we will present preliminary results of the study of NK cell immune response to various arrangements of ligands. This work provides a unique toolbox for the spatial control of diverse receptors within the cell membrane, that paves the way to numerous studies aimed at elucidating the molecular mechanism of signal integrating in cells, with the complexity and resolution impossible up to date.