Central memory-enriched Vγ9Vδ2 γδ T cells via TGF-β expansion demonstrate enhanced in vivo efficacy against metastatic osteosarcoma. (PubMed, Front Immunol)
Introducing zoledronate (ZOL) to OS cells augments γδ T cell killing by upregulating phosphoantigens in treated cells, which induces butyrophilin complexes, which are recognized by the TCR of the γδ T cell and significantly increases target cell death in both control and TGF-β expanded γδ T cells. In addition, administering ifosfamide (IFO), a chemotherapy used for relapsed OS, induces stress antigens in OS cell lines that are recognized by NKG2D receptors on γδ T cells, which enhances γδ T cell killing. In vivo studies show the administration of TGF-β expanded γδ T cells, when combined with ZOL and IFO significantly increased overall survival in OS-bearing mice, which we show can be attributed, at least in part, to increased persistence compared to control cells. Together, these data demonstrate this chemoimmunotherapy strategy, which engages various targeting mechanisms of γδ T cells, significantly enhances killing of OS.