Pattern and precision: DNA-based mapping of spatial rules for T cell activation.

Area of Science:

• Immunology
• Nanotechnology
• Biophysics

Background:

• T cell receptor (TCR) activation is crucial for adaptive immunity.
• The nanoscale organization of peptide-MHC class I (pMHC-I) ligands influences T cell function.
• A detailed understanding of pMHC-I spatial arrangement effects on CD8+ T cells is lacking.

Purpose of the Study:

• To investigate how the spatial arrangement of pMHC-I ligands affects T cell activation.
• To determine the roles of ligand valency, spacing, geometry, and flexibility in TCR signaling.
• To establish design principles for T cell-based immunotherapies.

Main Methods:

• Utilized DNA origami nanomaterials to precisely control pMHC-I spatial configurations.
• Systematically varied inter-ligand spacing, geometric patterns, and molecular flexibility.
• Measured T cell activation and signaling responses.

Main Results:

• Reduced inter-ligand spacing to ~7.5 nm increased T cell activation up to eightfold.
• As few as six pMHC-I molecules were sufficient for robust T cell activation.
• Hexagonal pMHC-I arrangements were most effective in enhancing signaling strength.
• Flexible linkers between pMHC-I molecules impaired TCR triggering.

Conclusions:

• Nanoscale spatial parameters critically govern pMHC-I-TCR interactions at the T cell interface.
• Defined spatial organization of ligands enhances T cell activation potential.
• Findings provide a foundation for engineering improved T cell immunotherapies.