mRNA-Engineered CD5-CAR-γδT^CD5- Cells for the Immunotherapy of T-Cell Acute Lymphoblastic Leukemia

Clinical trials of Chimeric Antigen Receptor T-cell (CAR-T) therapy have demonstrated remarkable success in treating both solid tumors and hematological malignancies. Nanobodies (Nbs) have emerged as promising antigen-targeting domains for CARs, owing to their high specificity, robust stability, and strong affinity, leading to significant advancements in the field of Nb-CAR-T. In the realm of T-cell acute lymphoblastic leukemia (T-ALL) targets, CD5 stands out as a potentially excellent candidate for T-cell-based CAR therapy, due to its distinct expression on the surface of malignant T-ALL cells. To mitigate graft-versus-host disease associated with allogeneic CAR-T, γδT cells are selected and stimulated from peripheral blood mononuclear cells, and γδT cells are engineered via CRISPR/Cas9 to eliminate fratricide, enabling the creation of fratricide-resistant CAR-γδT^CD5- cells. In vitro transcribed (IVT) mRNA is used to construct CAR-T, presenting a safer, faster, and cost-effective method compared to traditional viral vector approaches. In this study, a CD5-VHH library is constructed, and specific CD5-nanobodies are screened for subsequent use in CD5-CAR-γδT^CD5- therapy. IVT-mRNA-CD5-CAR-γδT^CD5- cells exhibited favorable functional characteristics and demonstrated antitumor efficacy against malignant T cell lines, underlining the potential for advancing mRNA-CD5-CAR-γδT^CD5- therapy.