Two Distinct Activation Methods Yield Clinical-Scale Expansion Of Peripheral Blood Derived γδ T Cells

By Chengkang Zhang, Amy Burkall, Elizabeth Kagan, Karen Roderick, Erin Brooks, Kenneth Low, Alexis Bossie

Gamma delta (γδ) T cells have the inherent ability to infiltrate solid tumors and directly recognize and kill transformed cells without relying on HLA-antigen presentation. Importantly, γδ T cells do not cause graft-versus-host disease, making them a promising platform for developing T-cell therapies targeting solid tumors. However, the low prevalence of γδ T cells in peripheral blood presents a challenge in generating sufficient quantities ex vivo for clinical use.

This study demonstrates the generation of billions of γδ T cells from peripheral blood mononuclear cells (PBMCs) using two distinct activation methods in TheraPEAK® T-VIVO® Medium, a chemically defined, non-animal origin, serum-free medium, on a rocking motion platform. The first method utilizes zoledronic acid as the activating agent and produces more than 1 billion Vδ2+ T cells within 14 days from an initial 0.5 billion PBMCs. In the second approach, either αβ T cells are specifically depleted from PBMCs or γδ T cells are isolated via negative selection before anti-CD3 and anti-CD28 co-stimulation. This approach yields billions of γδ T cells, including both Vδ1+ and Vδ2+ T cell subsets, from PBMCs. The expanded γδ T cells exhibit innate cytotoxicity towards the K562 cell line and produce cytokines such as IFN-γ and TNF-α in vitro. Both activation methods and expansion protocols may be suitable for generating enough γδ T cells to support clinical applications.