Immunological synapse arrays : patterned protein surfaces that modulate immunological synapse structure formation in T cells
Patterned protein surfaces that modulate immunological synapse structure formation in T cells
Massachusetts Institute of Technology. Dept. of Chemical Engineering.
Darrell J. Irvine.
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T cells are activated by recognition of foreign peptides displayed on the surface of antigen presenting cells (APCs), an event that triggers assembly of a complex microscale structure at the T cell-APC interface known as the immunological synapse (IS). It remains unresolved whether the unique physical structure of the synapse itself impacts the functional response of T cells, independent of the quantity and quality of ligands encountered by the T cell. As a first step toward addressing this question, we fabricated multicomponent protein surfaces that surrogate the role of APCs and studied T cell responses as a function of synapse structure. To pattern multiple proteins on surfaces, we synthesized and characterized a new polymer, poly(o-ntrobenzyl methacrylate-r-methyl methacrylate-poly(ethylene glycol) methacrylate (PNMP), a photoresist that can be processed under mild aqueous conditions. Based on the pH- and temperature-sensitive solubility of UV-exposed PNMP random terpolymers in aqueous buffers, two-component protein patterning was achieved under conditions that avoid exposing proteins to conditions outside the narrow range of physiological pH, ionic strength, and temperature where their stability is greatest.(cont.) Using a photolithographic strategy we developed employing this novel PNMP photoresist polymer, we created multicomponent protein surfaces presenting micron-scale arrays of tethered T cell receptor (TCR) ligands (anti-CD3 'activation sites') surrounded by a field of tethered intercellular adhesion molecule-I (ICAM-1), as a model substrate on which T cells could be seeded to mimic T cell-APC interactions. CD4+ T cells seeded on these surfaces polarized and migrated; on contact with activation sites, T cells assembled an IS with a structure modulated by the physical pattern of ligand encountered. On surfaces patterned with focal spots of TCR ligand, T cells stably interacted with activation sites, proliferated, and secreted cytokines. In contrast, T cells interacting with activation sites patterned to preclude centralized clustering of TCR ligand failed to form stable contacts with activation sites, exhibited aberrant PKC-[Theta] clustering in a fraction of cells, and had significantly reduced production of interferon-[gamma]. These results suggest that focal clustering of TCR ligand characteristic of the 'mature' IS may be required under some conditions for full T cell activation.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2006.Vita.Includes bibliographical references (leaves 128-137).
DepartmentMassachusetts Institute of Technology. Dept. of Chemical Engineering.; Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology