Large Scale Ex Vivo Expansion of γδ T cells Using Artificial Antigen-presenting Cells

Higher gamma delta T cell counts in patients with malignancies are associated with better survival. However, gamma delta T cells are rare in the blood and functionally impaired in patients with malignancies. Promising results are reported on the treatment of various malignancies with in vivo expansion of autologous gamma delta T cells using zoledronic acid (zol) and interleukin-2 (IL-2). Here we demonstrated that zol and IL-2, in combination with a novel genetically engineered K-562 CD3scFv/CD137L/CD28scFv/IL15RA quadruplet artificial antigen-presenting cell (aAPC), efficiently expand allogeneic donor-derived gamma delta T cells using a Good Manufacturing Practice (GMP) compliant protocol sufficient to achieve cell doses for future clinical use. We achieved a 633-fold expansion of gamma delta T cells after day 10 of coculture with aAPC, which exhibited central (47%) and effector (43%) memory phenotypes. In addition, >90% of the expanded gamma delta T cells expressed NKG2D, although they have low cell surface expression of PD1 and LAG3 inhibitory checkpoint receptors. In vitro real-time cytotoxicity analysis showed that expanded gamma delta T cells were effective in killing target cells. Our results demonstrate that large-scale ex vivo expansion of donor-derived gamma delta T cells in a GMP-like setting can be achieved with the use of quadruplet aAPC and zol/IL-2 for clinical application.

Automated summary

Higher gamma delta T cell counts in patients with malignancies are associated with better survival. Promising results are reported on the treatment of various malignancies with in vivo expansion of autologous gamma delta T cells using zoledronic acid (zol) and interleukin-2 (IL-2). In this study, we demonstrated that a combination of zol and IL-2, along with a novel genetically engineered aAPC, effectively expanded allogeneic donor-derived gamma delta T cells in large quantities for potential clinical use.