Introduction
Chimeric antigen receptor-engineered T (CAR-T) cells have shown success in hematologic malignancies, while T cell receptor-engineered T (TCR-T) cells have recently entered clinical use in solid tumors. CAR-T cells target surface antigens and efficiently deliver co-stimulatory signals, whereas TCR-T cells target intracellular antigens and can harness lymphoid priming and the cancer-immunity cycle. Although co-expression of a tumor-specific TCR and a CAR has been studied in xenograft models, whether this dual-receptor strategy confers a clear therapeutic advantage in immunocompetent syngeneic models remains insufficiently established.
Materials and methods
In this study, using a human CD19–expressing B16F10 melanoma mouse model (B16F10-hCD19), we evaluated gp100-specific Pmel-1 TCR-expressing T (TCR-T) cells, CD19-targeted CD28ζ CAR-T cells, and dual-receptor T cells co-expressing the TCR and the CAR (DualR-T). We assessed in vivo efficacy and in vitro functions such as polyfunctionality, cytotoxicity, and proliferation. In addition, we tracked engineered T cells in vivo and quantified longitudinal biodistribution in lymphoid and tumor tissues using IVIS imaging and droplet digital PCR (ddPCR).
Results and discussion
In B16F10-hCD19–bearing C57BL/6 mice, DualR-T cells achieved the greatest in vivo antitumor efficacy, with CAR-T cells showing intermediate tumor control and TCR-T cells the least. In vitro functional analyses showed that polyfunctionality and cytotoxicity differed among TCR-T, CAR-T, and DualR-T cells under prolonged co-culture stress conditions with B16F10-hCD19 tumor cells. Longitudinal in vivo tracking suggested distinct in vivo behavior, with DualR-T cells showing relatively higher early lymphoid signal, a later increase in systemic signal, and more sustained tumor accumulation over time than CAR-T cells. These kinetic features were associated with improved antitumor activity, suggesting that the superior efficacy of DualR-T cells relates more closely to advantageous in vivo trafficking and kinetics than to enhanced in vitro functionality alone.
Conclusions
This study supports an advantage of integrating antigen-presenting cell-dependent priming with enforced co-stimulatory signaling in adoptive T cell therapy for solid tumors. Importantly, these findings were obtained in a syngeneic solid tumor model that enables evaluation of in vivo dynamics within an intact host immune system, which are not fully captured in xenograft settings. Together, our findings suggest that this integrated signaling framework can be leveraged to guide the development of more effective T-cell therapies for solid tumors.
Acknowledgements
This work was supported by the National Cancer Center of Korea (NCC) grant funded by the Ministry of Health and Welfare (NCC-24H1041 [C.H.]) and the National Research Foundation of Korea (NRF) grants funded by the Ministry of Science and ICT (2022R1C1C1010078 [S.-H.K.] and 2022R1C1C1003152 [C.H.]).