Targeting pediatric High-Grade Gliomas with OAcGD2-CAR Vδ2 T cells

Purpose: Pediatric high-grade gliomas (pHGG) belong to a family of rare children's cancers which are treated with radiotherapy, based on adult high-grade glioma standard of care. However, new treatments are definitively required since actual ones are unable to extend survival by more than a few months in most patients. In this study, we investigate a Chimeric Antigen Receptor (CAR)-T cell immunotherapy targeting the OAcGD2 ganglioside, using either conventional αβ or Vδ2 T cells as effectors. Materials and methods: Using relevant human primary models of pHGG, we first characterized the innate Vδ2 T cell immunoreactivity. Then, following the validation of OAcGD2 expression in these tumor cells, we evaluated both αβ and Vδ2 OAcGD2-CAR-T cell immunoreactivity using various methods including videomicroscopy, FACS and cytotoxicity assays. Results: We showed that pHGG primary cells are not spontaneously recognized and killed by Vδ2 T cells but significantly expressed the OAcGD2 ganglioside. Accordingly, both αβ and Vδ2 T cells engineered to express a CAR against the OAcGD2 efficiently killed pHGG cells in 2D and 3D models. Importantly, only Vδ2 T cells transduced with the complete OAcGD2-CAR eliminated pHGG cells, in contrast to conventional αβ CAR-T cells that killed tumor cells even in the absence of CAR expression, highlighting the allogeneic potential of Vδ2 CAR-T cells. Conclusion: Our study demonstrates the preclinical relevance of targeting OAcGD2 in pHGG using CAR-T cells. Furthermore, we also clearly demonstrate the clinical benefits of using Vδ2 T cells as CAR effectors in allogeneic settings allowing an off-the-shelf immunotherapy. ### Competing Interest Statement SF, BC and SB are inventors of granted patents covering the therapeutic uses of monoclonal antibodies targeting O-acetylated GD2 ganglioside. SB is a shareholder of the OGD2 Pharma company.