Towards programming immune tolerance through geometric manipulation of phosphatidylserine

Area of Science:

• Biomaterials Science
• Immunology
• Nanotechnology

Background:

• Engineering the immune system with biomaterials like nanoparticles is advancing.
• The impact of ligand spatial presentation on immune responses is not well understood.

Purpose of the Study:

• To investigate how geometric manipulation of phosphatidylserine (PS) on nanoparticles affects immune cell responses.
• To explore the therapeutic potential of geometrically controlled PS presentation in disease models.

Main Methods:

• Fabrication of rod-shaped PLGA nanoparticles presenting phosphatidylserine (PS).
• Assessment of immune cell responses to varying PS geometries (rod-shaped nanoparticles vs. liposomes vs. cylindrical particles).
• Evaluation of therapeutic efficacy in a mouse model of multiple sclerosis and a human mixed lymphocyte reaction assay for organ rejection.

Main Results:

• Rod-shaped PS-PLGA nanoparticles significantly dampened innate immune cell inflammatory responses compared to other geometries.
• This geometric presentation promoted T regulatory cell abundance by inhibiting effector T cell expansion.
• Therapeutic benefits were observed in a mouse model of multiple sclerosis and an organ rejection assay.

Conclusions:

• Geometric control of ligand presentation on biomaterials, specifically rod-shaped nanoparticles, can program immune responses.
• This approach offers a tunable strategy for dampening harmful immune reactions and holds promise for treating autoimmunity and preventing organ rejection.