Activating and Propagating Polyclonal Gamma Delta T Cells with Broad Specificity for Malignancies

Purpose: To activate and propagate populations of gamma delta T cells expressing polyclonal repertoire of gamma and delta T-cell receptor (TCR) chains for adoptive immunotherapy of cancer, which has yet to be achieved. Experimental Design: Clinical-grade artificial antigen-presenting cells (aAPC) derived from K562 tumor cells were used as irradiated feeders to activate and expand human gamma delta T cells to clinical scale. These cells were tested for proliferation, TCR expression, memory phenotype, cytokine secretion, and tumor killing. Results: gamma delta T-cell proliferation was dependent upon CD137L expression on aAPC and addition of exogenous IL2 and IL21. Propagated gamma delta T cells were polyclonal as they expressed TRDV1, TRDV2-2, TRDV3, TRDV5, TRDV7, and TRDV8 with TRGV2, TRGV3F, TRGV7, TRGV8, TRGV9* A1, TRGV10* A1, and TRGV11 TCR chains. IFN gamma production by V delta 1, V delta 2, and V delta 1(neg)V delta 2(neg) subsets was inhibited by pan-TCR gamma delta antibody when added to cocultures of polyclonal gamma delta T cells and tumor cell lines. Polyclonal gamma delta T cells killed acute and chronic leukemia, colon, pancreatic, and ovarian cancer cell lines, but not healthy autologous or allogeneic normal B cells. Blocking antibodies demonstrated that polyclonal gamma delta T cells mediated tumor cell lysis through combination of DNAM1, NKG2D, and TCR gamma delta. The adoptive transfer of activated and propagated gd T cells expressing polyclonal versus defined V delta TCR chains imparted a hierarchy (polyclonal>V delta 1>V delta 1(neg)V delta 2(neg)>V delta 2) of survival of mice with ovarian cancer xenografts. Conclusions: Polyclonal gamma delta T cells can be activated and propagated with clinical-grade aAPCs and demonstrate broad antitumor activities, which will facilitate the implementation of gamma delta T-cell cancer immunotherapies in humans. (C) 2014 AACR.