CDR3δ-grafted γ 9δ2T cells mediate effective antitumor reactivity

Abstract

Adoptive cell-transfer therapy (ACT) has been reported to suppress growing tumors and to overcome tumor escape in animal models. As a candidate ACT effector, δ 9γ2T cells can be activated and expanded in vitro and in vivo and display strong antitumor activity against colorectal, lung, prostate, ovarian and renal cell carcinomas. However, it is difficult to obtain a large enough number of γ δ cells to meet the need for immunotherapy that can overcome the cancer patients' immune suppressive tumor microenvironment. In previous studies, our lab confirmed that δ 9γ 2T cells recognized tumor cells via the CDR3δ region of the γ δ -T-cell receptor (TCR). We constructed full-length human peripheral blood mononuclear cell (PBMC)-derived δ39 and δ 2 chains in which the CDR3 region was replaced by an ovarian epithelial carcinoma (OEC)-derived CDR3. We transferred the CDR3δ-grafted δ 9γ 2TCR into peripheral blood lymphocytes (PBLs) to develop genetically modified γ 9δ 2T cells. In vitro studies have shown that these CDR3δ-grafted γ9δ 2T cells can produce cytokines after stimulation with tumor cell extracts and exhibit cytotoxicity towards tumor cells, including human OEC and cervical adenocarcinoma. CDR3δ -grafted δ 9δ 2T cells adoptively transferred into nude mice bearing a human OEC cell line demonstrated significant antitumor effects. These results indicate that CDR3δ-grafted γ9δ2T cells might be candidates for clinical tumor immunotherapy. © 2012 CSI and USTC. All rights reserved.