In Vitro Expansion of V delta 1+ T Cells from Cord Blood by Using Artificial Antigen-Presenting Cells and Anti-CD3 Antibody

gamma delta T cells have the potential for adoptive immunotherapy since they respond to bacteria, viruses, and tumors. However, these cells represent a small fraction of the peripheral T-cell pool and require activation and proliferation for clinical benefits. In cord blood, there are some gamma delta T cells, which exhibit a naive phenotype, and mostly include V delta 1+ T cells. In this study, we investigated the effect of CD3 signaling on cord blood gamma delta T-cell proliferation using K562-based artificial antigen presenting cells expressing costimulatory molecules. There were significantly more V delta 1+ T cells in the group stimulated with anti-CD3 antibody than in the group without. In cultured V delta 1+ T cells, DNAM-1 and NKG2D were highly expressed, but NKp30 and NKp44 showed low expression. Among various target cells, V delta 1+ T cells showed the highest cytotoxicity against U937 cells, but Daudi and Raji cells were not susceptible to V delta 1+ T cells. The major cytokines secreted by V delta 1+ T cells responding to U937 cells were Granzyme B, IFN-gamma, and sFasL. Cytotoxicity by V delta 1+ T cells correlated with the expression level of PVR and Nectin of DNAM-1 ligands on the surface of target cells. Compared to V delta 2+ T cells in peripheral blood, cord blood V delta 1+ T cells showed varying cytotoxicity patterns depending on the target cells. Here, we determined the ideal conditions for culturing cord blood V delta 1+ T cells by observing that V delta 1+ T cells were more sensitive to CD3 signals than other subtypes of gamma delta T cells in cord blood. Cultured cord blood V delta 1+ T cells recognized target cells through activating receptors and secreted numerous cytotoxic cytokines. These results are useful for the development of tumor immunotherapy based on gamma delta T cells.