Characterisation and induction of tissue-resident gamma delta T-cells to target hepatocellular carcinoma

Immunotherapy is now the standard of care for advanced hepatocellular carcinoma (HCC), yet many patients fail to respond. A major unmet goal is the boosting of T-cells with both strong HCC reactivity and the protective advantages of tissue-resident memory T-cells (T-RM). Here, we show that higher intratumoural frequencies of gamma delta T-cells, which have potential for HLA-unrestricted tumour reactivity, associate with enhanced HCC patient survival. We demonstrate that gamma delta T-cells exhibit bona fide tissue-residency in human liver and HCC, with gamma delta T-RM showing no egress from hepatic vasculature, persistence for >10 years and superior anti-tumour cytokine production. The V gamma 9V delta 2 T-cell subset is selectively depleted in HCC but can efficiently target HCC cell lines sensitised to accumulate isopentenyl-pyrophosphate by the aminobisphosphonate Zoledronic acid. Aminobisphosphonate-based expansion of peripheral V gamma 9V delta 2 T-cells recapitulates a T-RM phenotype and boosts cytotoxic potential. Thus, our data suggest more universally effective HCC immunotherapy may be achieved by combining aminobisphosphonates to induce V gamma 9V delta 2T(RM) capable of replenishing the depleted pool, with additional intratumoural delivery to sensitise HCC to V gamma 9V delta 2T(RM)-based targeting. Many cancer immune therapy approaches depend on an HLA-restricted neoantigen-specific T cell response. AUs show here that Zoledronic acid can expand, and induce tumour recognition by, a population of tissue resident memory gamma-delta T cells associated with an efficient anti-tumour immune response in hepatocellular carcinoma.