Chimeric Antigen Receptors Transmit Co-stimulatory Domain Dependent Piconewton Forces to their Target

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• Chimeric antigen receptor (CAR) T cells are engineered immune cells for cancer therapy.
• Native T cells utilize mechanical forces for signaling, but CAR T cell forces remain unquantified.
• Mechanoactivity is increasingly recognized as important in CAR T cell function.

Purpose of the Study:

• To directly measure forces transmitted by CAR T cells.
• To investigate the relationship between CAR T cell forces and early signaling events.
• To identify factors influencing CAR-mediated force transmission.

Main Methods:

• Utilized DNA-based molecular tension probes (MTPs) attached to CAR target ligands.
• Measured forces transmitted by clinically relevant CARs (CD123, CD33, CD19).
• Assessed the role of intracellular co-stimulatory domains and TCR signaling machinery.

Main Results:

• CAR T cells transmit actin-polymerization dependent forces ranging from 4.7-19 pN.
• Force transmission is demonstrated across multiple CAR targets and constructs.
• Intracellular co-stimulatory domains are key determinants of CAR-mediated forces; first-generation CARs lack measurable force transmission.
• CAR forces precede Ca2+ signaling and correlate with TCR signaling pathway phosphorylation.

Conclusions:

• CAR-mediated mechanobiology is a significant factor in early CAR T cell activation.
• CAR T cell forces are linked to biochemical signaling cascades, offering new insights into CAR T cell function.
• Understanding CAR T cell mechanobiology may enhance the efficacy of CAR T cell-based cancer immunotherapies.