Adoptive transfer of T cells engineered to express chimeric antigen receptors (CARs) can induce durable regressions in cancer patients, particularly in the treatment of B-cell malignancies. The production and expansion of CAR-T cells relies on in vitro T-cell stimulation and more work is needed to explore the phenotypic changes that occur in this process to elucidate features that are predictive of anti-tumor functionality. Here, we present a systematic study of T cells expressing a second-generation, anti-CD19 CAR and use flow cytometry to interrogate the dynamic phenotypic and functional changes exhibited by CAR-T cells undergoing varied antigen stimulation courses. By tracking CAR–T-cell viability, proliferation, cytokine production, lytic abilities, and expression of various T-cell activation markers and inhibitory receptors across time, we find that CAR-T cells consistently bifurcate into two distinct subpopulations with dramatically different functional capacities and surface marker expression profiles. Furthermore, the proportion of CAR-T cells that demonstrate the superior functions is dependent on the particular degree of antigen stimulation and the composition of the T cell population (CD4 vs CD8, T-cell memory compartment breakdown, % transduced). Altogether, the systematic characterization methods and results reported here can guide future efforts to improve CAR–T-cell therapies.
Citation Format: ZeNan L. Chang, Pamela A. Silver, Yvonne Y. Chen. Functional bifurcation in T cells expressing chimeric antigen receptors. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B022.
- ©2016 American Association for Cancer Research.