Fluid shear stress as a co-stimulatory cue to enhance T cell priming and restore activation in cancer patient T cells.

Cancer patient-derived T cells often exhibit impaired activation and functional responsiveness due to chronic antigen exposure and therapy-induced immune dysregulation, limiting the efficacy of current immunotherapies. Mechanical forces, such as fluid shear stress (FSS), are emerging as critical regulators of immune cell activation, yet their role in modulating activation of patient-derived T cells remains largely unexplored. In this study, primary T cells isolated from patients with metastatic prostate cancer were exposed to FSS using a cone-and-plate viscometer during ex vivo activation in the presence and absence of bead-bound anti-CD3/CD28 monoclonal antibodies. FSS alone was sufficient to induce NF-κB phosphorylation and intracellular cytokine synthesis, demonstrating that mechanical stimulation can independently initiate T cell activation signaling. Moreover, FSS combined with anti-CD3/CD28 stimulation produced a synergistic increase in activation signaling, IL-2 and IFN-γ production, and CD25/CD69 expression. While trends were consistent across donors overall, inter-patient variability reflected differences in baseline T cell phenotype, with naïve-like cells displaying greater mechanosensitivity. These results indicate that cancer patient-derived T cells retain mechanotransduction capacity despite reduced antigen responsiveness. Incorporating FSS as a co-stimulatory signal during ex vivo expansion may be more effective at priming patient T cells for activation, enhancing effector function, and improving the efficacy of adoptive cell therapies.