The ex vivo production of T-cells that can recognize tumor-associated antigens (TAAs) and through this recognition eliminate cancer cells is the goal of T-cell-based adoptive cellular immunotherapy (ACI). The technological approaches that use whole cancer cells or their pertinent lysates as a source of TAAs for production of these T-cells lead to generation of polyclonal T-cells their antigen specificity of which is often unknown. Evaluation of such polyclonal T-cells is therefore challenging because their target and off-target performance might be difficult to predict. In our study we used human dendritic cells (DCs) pulsed with inactivated prostate cancer cell line LNCaP and matured with polyinosinic:polycytidylic acid (poly(I:C)) to induce expansion of autologous lymphocytes. The expanded lymphocytes were then challenged with live LNCaP cells and analyzed by simultaneous detection of a marker of T-cell cytotoxicity and antigen-induced T-cell stimulation, the surface externalization of, respectively, CD107a and CD137. Our data showed that lymphocytes expanded with LNCaP-pulsed and poly(I:C)-matured DCs contained a notable fraction of CD137 and/or CD107a positive T-cells after their challenge with live LNCaP cells. No such notable fraction was however observed in resting lymphocytes, or when the lymphocytes were challenged with ovarian cancer cell line SKOV-3. Importantly, autologous lymphocytes that were expanded with poly(I:C)-matured DCs not previously pulsed with the inactivated LNCaP cells did not show a notable population of the marker positive cells. Collectively, our data showed that simultaneous detection of externalized CD107a and CD137 on the surface of polyclonal T-cells may allow for evaluation of polyclonal T-cell specificity and effector functions after their challenge with complex antigens.

Citation Format: Pavla Taborska, Dmitry Stakheev, Katerina Vavrova, Petra Vrabcova, Jirina Bartunkova, Daniel Smrz. Use of simultaneous detection of externalized CD107a and CD137 for evaluation of specificity and effector functions of polyclonal T-cells produced for adoptive cellular immunotherapy of prostate cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B065.