Chimeric Antigen Receptors Transmit Piconewton Forces that are Coupled with T Cell Function

Area of Science:

• Immunology
• Biophysics
• Cancer Therapy

Background:

• Chimeric antigen receptor (CAR) T cells are engineered for cancer immunotherapy.
• The role of piconewton (pN) forces in T cell receptor (TCR) function is increasingly recognized.
• The presence and significance of mechanical forces in CAR T cell interactions remain largely unexplored.

Purpose of the Study:

• To investigate the mechanical forces transmitted by CAR T cells to their target antigens.
• To explore the potential of CAR-antigen forces as biomarkers for T cell potency and fitness.
• To elucidate the molecular mechanisms underlying CAR T cell force generation and transmission.

Main Methods:

• Utilized DNA-based tension probes to measure forces between CAR T cells and target antigens.
• Employed an established CAR T cell exhaustion model to correlate force with cytotoxic capacity.
• Conducted pharmacological inhibition studies targeting key signaling molecules (actin, Zap70, Src kinases).
• Performed structural engineering of CAR components to assess their impact on force transmission.

Main Results:

• CAR T cells transmit 8-19 pN forces to target antigens on a timescale of ~1 second.
• CAR-antigen force magnitude is independent of CAR expression level but shows donor heterogeneity.
• CAR-antigen force strongly correlates with CAR exhaustion and cytotoxic capacity.
• CAR forces are dependent on actin, Zap70, Src family kinases, and CD3ζ ITAMs.
• Dasatinib, a tyrosine kinase inhibitor, dose-dependently reduces both CAR-antigen force and function.

Conclusions:

• CAR T cells actively transmit piconewton forces to their cognate antigens.
• CAR-antigen mechanical force is a potential biomarker for T cell fitness, potency, and exhaustion.
• Understanding CAR mechanics offers insights into CAR T cell design and personalized treatment strategies.
• These findings highlight the significance of mechanical forces in CAR T cell-mediated immunotherapy.