Research Insight - Antibody-Mediated Chemical Engineering of γδ T Cells Targeting Cancer Cells for Enhanced Tumor Immunotherapy

Recently, Researcher Jian Lin and Associate Researcher Long Chen from the Department of Pharmacy, Peking University Third Hospital, in collaboration with Professor Xing Chen from the College of Chemistry and Molecular Engineering, Peking University, and Professor Hongyan Guo, Director of the Department of Gynecology at Peking University Third Hospital, have made new advances in γδ T cell–based tumor immunotherapy. The related findings have been published in the internationally authoritative journal National Science Review (IF = 17.1, top-tier journal).

γδ T cells, as a unique subset of T lymphocytes, possess several advantages, including recognition of tumor antigens independent of major histocompatibility complex (MHC), the feasibility of allogeneic infusion, and the absence of graft-versus-host disease (GVHD) risk. These features confer broad application prospects in adoptive cell therapy. γδ T cells have been demonstrated to exert antitumor activity both in vitro and in vivo, making them a focal point in tumor immunotherapy research. However, conventionally expanded, non-engineered γδ T cells exhibit significant limitations: on the one hand, their tumor-targeting efficiency is low, making precise localization and action on tumor cells difficult; on the other hand, their activation capacity after infusion is limited, resulting in suboptimal clinical benefits. To overcome these challenges, attempts have been made to engineer γδ T cells using chimeric antigen receptor (CAR) technology. However, genetic engineering approaches are costly and time-consuming for large-scale production. Meanwhile, cell surface chemical engineering has emerged as a flexible strategy for modulating immune cell functions and has shown promise in studies involving natural killer (NK) cells and αβ CAR-T cells. Therefore, exploring chemical engineering approaches to confer tumor-targeting capability to γδ T cells, thereby enhancing their antitumor activity while simplifying the production process, represents a key direction for addressing current limitations in γδ T cell therapy.

Based on this premise, the present study successfully developed a cell surface chemical engineering strategy for γδ T cells based on metabolic glycan labeling and click chemistry. Sialic acid on the cell surface (as the terminal sugar of cell surface glycans) was identified as the optimal anchoring site for antibody conjugation. Using fast metabolic glycan labeling (fMGL) technology, anti–PD-L1 nanobodies (αPD-L1) were efficiently and stably conjugated onto the surface of γδ T cells, generating αPD-L1–γδ T cell conjugates. Functional validation demonstrated that these conjugates exhibited significantly enhanced cytotoxic activity in vitro against PD-L1–positive cancer cell lines (such as ovarian cancer cell lines OVCAR-8 and A2780-DDP) as well as primary tumor cells derived from patients. Mechanistically, this effect is achieved by binding to PD-L1 to target tumor cells and inducing pyroptosis. In a mouse model of peritoneal metastasis of ovarian cancer, αPD-L1–γδ T cells effectively inhibited tumor growth and prolonged survival. Moreover, they recruited and activated CD8⁺ T cells via the CCR5/CCL5 signaling axis, thereby remodeling the tumor immune microenvironment and further strengthening antitumor immune responses. In addition, this chemical engineering strategy demonstrates strong versatility, enabling the conjugation of various functional molecules (e.g., GFP, DNA aptamers), while avoiding the high cost and complexity associated with genetic engineering. This provides a novel platform for optimizing γδ T cell–based adoptive cell therapy and holds significant implications for advancing the development of cancer “living drugs.”

In this study, to evaluate the effect of αPD-L1–γδ T cells on tumor growth in a mouse model of ovarian cancer peritoneal metastasis, an AniView multimodal in vivo imaging system (Guangzhou Biolight Biotechnology Co., Ltd.) was employed for observation. The results showed that, in the vehicle (PBS)-treated group, tumor bioluminescence signals continuously increased, indicating sustained tumor growth. In parallel, body weight decreased significantly with tumor progression, reflecting tumor-induced systemic wasting and deterioration of overall health status. In the group treated with non-engineered γδ T cells, tumor growth was inhibited to a certain extent, as evidenced by a slower increase in bioluminescence signals; however, the inhibitory effect remained limited. In contrast, mice treated with αPD-L1–γδ T cells exhibited markedly weaker tumor bioluminescence signals compared to the other groups, with progressively enhanced suppression over time. Additionally, the latter two groups maintained better body weight. These findings demonstrate that αPD-L1–γδ T cells exert a more potent inhibitory effect on the growth of PD-L1–positive ovarian cancer peritoneal metastases in vivo, further validating the superior antitumor efficacy of this cell conjugate.

Article link：

https://doi.org/10.1093/nsr/nwaf256