17 mars 2026
Ma et al. bioRxiv
Keywords
● CD16a
● NK cells
● Mechanotransduction
Main Findings
Natural killer (NK) cells mediate antibody-dependent cellular cytotoxicity (ADCC) through the Fc receptor CD16a, yet how receptor engagement leads to activation remains incompletely understood. In particular, clustering-based models do not explain why soluble Fc multimers can inhibit effector functions.
Ma et al. investigate whether CD16a signalling depends on mechanical forces. Using NK92 reporter cells expressing CD16a together with live-cell signalling reporters and DNA-based molecular tension probes, the authors show that immobilised IgG1 Fc—but not soluble Fc—induces calcium flux and ERK activation. CD16a engagement generates forces in the ~4–12 pN range, and signalling occurs even below probe unfolding thresholds, indicating that mechanical resistance, rather than force magnitude alone, supports activation.
Mechanistically, actin dynamics are required for force generation and signalling. Disruption of actin polymerisation abolishes both CD16a-mediated signalling and measurable forces. Actin foci form at sites of receptor engagement and colocalise with force transmission and phosphorylation of the adaptor proteins Cas-L and LAT, suggesting that actin-driven forces organise signalling hubs. These findings are recapitulated in primary human NK cells, supporting physiological relevance.
Limitations
The study focuses primarily on signalling readouts (calcium flux and ERK phosphorylation) and does not directly assess cytotoxic function (ADCC).
Most mechanistic experiments rely on the NK92 cell line, although key findings are validated in primary NK cells.
The causal role of Cas-L in mechanotransduction is not directly tested.
For the experiment using K56s cells these cells can activate NK cells via CD16a-independent receptor-ligand interactions and a cleaner system for example using CEM.NKR cells could have been used.
Significance/Novelty
The study focuses primarily on signalling readouts (calcium flux and ERK phosphorylation) and does not directly assess cytotoxic function (ADCC).
Most mechanistic experiments rely on the NK92 cell line, although key findings are validated in primary NK cells. More broadly, they suggest that the mechanical properties of antibody–receptor interactions may influence therapeutic efficacy, with potential implications for the design of antibody-based therapies and NK-cell engagers.Preprint rating
Scientific quality 4/5
Novelty 4.5/5
Significance 4.5/5
Credit
Reviewed by Maria Armero as part of a cross-institutional journal club between the Icahn School of Medicine at Mount Sinai, the University of Oxford, the Karolinska Institute and the University of Toronto.
The author declares no conflict of interests in relation to their involvement in the review.