Ultrasound and microbubble mediated T cell modulation in peripheral blood mononuclear cells

Ultrasound (US)-stimulated microbubbles are emerging as a revolutionary therapeutic technique, notably within the field of cancer immunotherapy. While this approach has been shown to modify cell permeability and to trigger local anti-tumor effects, the interactions between vibrating microbubbles and T-cells is not well understood. Here, we explore the biophysical impact of microbubbles on T-cell permeability and viability, setting the stage for potential advancements in cellular immunotherapy. Following the activation of fresh human peripheral blood mononuclear cells (PBMCs), cells were incubated with FITC-dextran (10kDa)—used here as a surrogate drug– and exposed in the presence of DefinityTM(1:217–cell:bubble ratio) US (1MHz, N = 1000, PRF = 5 ms for 2 minutes) over a range of peak-negative pressures (208-563kPa). Viability was assessed immediately and post-treatment concurrently with FITC macromolecule uptake using flow cytometry. T-cell population was identified using CD3 and CD4 antibodies (60% CD3 + and 20% CD4+). All conditions examined resulted > 95% viability. Results indicated a significant increase in viably permeated PBMCs with higher acoustic pressures, ranging from 0% to 30% (sham-corrected). When analyzed separately both CD4 + and CD4- T-cells exhibited similar permeability rates (0%–37.5%). The 563 kPa condition yielded the highest permeability with minimal viability loss. These findings open avenues for enhancing the efficacy of cellular immunotherapy for solid tumors.