Voice of China | Professor Di Wen's Team: Trispecific Antibodies Uncover Novel Insights into Immunotherapy for Solid Tumors—Dual Mechanisms to Activate Immunologically Cold Tumors
Professor Di Wen, Research Fellow Yang Fan, Research Fellow Zhuang Guanglei, and other scholars from Renji Hospital, Shanghai Jiao Tong University School of Medicine, jointly published a landmark research achievement in Nature Biomedical Engineering (IF=26.6). The team independently developed a novel trispecific antibody, B7H3xCD3xPDL1, which innovatively integrates three core functions: tumor targeting, T cell activation, and immune microenvironment remodeling. Through a unique IFNγ-IL-15 positive feedback loop, the antibody successfully activates bystander T cells in the tumor microenvironment and reverses the immunosuppressive state, thereby providing an entirely new therapeutic approach for intractable solid tumors such as ovarian cancer and colorectal cancer. This groundbreaking achievement has garnered high recognition from the global academic community.
Source: Nature Biomedical Engineering
I. Dual Bottlenecks in Solid Tumor Immunotherapy Awaiting Breakthroughs
The advent of immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment, yet a large proportion of patients fail to respond. The core challenges boil down to two key issues:
Scarcity of tumor-specific T cellsMost solid tumors (e.g., pancreatic cancer, ovarian cancer, glioblastoma) exhibit low mutation burden and insufficient neoantigens, resulting in a paucity of tumor-specific T cells capable of recognizing cancer cells. This renders ICIs largely ineffective.
Severe immunosuppression in the tumor microenvironmentMyeloid cells such as tumor-associated macrophages highly express immune checkpoint molecules like PDL1 and secrete inhibitory factors. Even when abundant bystander T cells (non-tumor-specific T cells) are present in the tumor, their cytotoxic functions are severely impaired.
Previously approved bispecific T cell engagers (Bi-TCEs) can activate bystander T cells but fail to reverse the immunosuppressive microenvironment, limiting their efficacy in solid tumors. Addressing this critical gap, Professor Di Wen’s team proposed a dual-action therapeutic strategy of “T cell activation + microenvironment remodeling” and developed a novel trispecific antibody with triple-targeting capabilities.
Figure 1: Presence of potentially functional T cells in the immunologically cold tumor microenvironment
II. Design and Dual Mechanisms of Action of the Trispecific Antibody
Based on the team’s independently established TROY-Ig antibody platform, the B7H3xCD3xPDL1 trispecific antibody was successfully constructed, with its structural design precisely tailored to therapeutic needs:
Dual Fab arms targeting the pan-cancer antigen B7H3: Ensures tumor-specific binding and minimizes off-target effects.
Low-affinity CD3-binding domain: Gently activates T cells (including bystander T cells) and reduces the risk of systemic immune activation.
PDL1-binding domain: Acts both as an immune checkpoint blocker and a bridge molecule between immune cells, mediating functional crosstalk between T cells and myeloid cells.
Figure 2: Efficacy evaluation of bispecific/trispecific T cell engagers in multiple primary human systems
Key Mechanism of Action: The IFNγ-IL-15 Positive Feedback Loop
Precise T cell activationThe antibody simultaneously binds to B7H3 on tumor cells and CD3 on T cells, forming an immunological synapse. This converts bystander T cells (originally lacking tumor-recognition ability) into cytotoxic T cells, which secrete perforin and granzyme to directly lyse tumor cells.
Macrophage reprogrammingActivated T cells secrete IFNγ, which induces the reprogramming of immunosuppressive macrophages into an immunostimulatory phenotype with high expression of pro-immune factors such as IL-15.
Sustained functional amplificationIL-15 further promotes T cell proliferation and differentiation into effector memory T cells. Meanwhile, IFNγ upregulates PDL1 expression on macrophages, recruiting more immune cells into the loop. This forms a “activation-secretion-reactivation” positive feedback cycle, achieving a potent “defeat the many with the few” anti-tumor effect.
III. Landmark Data: Robust and Safe Anti-tumor Efficacy Validated in Multiple Models
1. In Vitro and Patient Sample Validation: Cross-cancer Efficient Tumor Killing
In co-culture systems, the half-maximal effective concentration (EC50) of B7H3xCD3xPDL1 was only 1/7 that of the bispecific antibody (94.5 ng/ml vs. 691.5 ng/ml), achieving nearly complete elimination of the ovarian cancer cell line SKOV3.
In 21 cases of patient-derived tumor suspensions (PDTS) covering ovarian cancer, colorectal cancer, non-small cell lung cancer, bladder cancer, etc., the antibody significantly upregulated the expression of CD8⁺ T cell activation markers (CD25), proliferation markers (Ki67), and cytokines (IFNγ, TNF). The tumor killing rate was 2–3 times higher than that of the bispecific antibody.
In the patient-derived tumor fragment (PDTF) model (preserving the in situ tumor microenvironment), the infiltration of functional T cells (CD3⁺GZMB⁺) increased 3-fold, the proportion of tumor cells decreased by 40%, and the average distance between T cells and tumor cells shortened from 150 μm to 50 μm.
2. Humanized Mouse Model: Complete Tumor Eradication with Excellent Safety Profile
In humanized NOG mice implanted with SKOV3 ovarian cancer cells:
Tumor volume in the B7H3xCD3xPDL1 treatment group was reduced by over 90% compared to the control group, with nearly half of the mice achieving complete tumor clearance; in contrast, the bispecific antibody group only exhibited mild tumor growth inhibition.
Mice maintained stable body weight after treatment, with normal liver and kidney function indicators. No obvious organ toxicity or severe graft-versus-host disease (GVHD) was observed.
The antibody also demonstrated potent anti-tumor efficacy in models such as A375 melanoma and Detroit 562 head and neck squamous cell carcinoma, verifying its cross-cancer applicability.
Figure 3: Potent anti-tumor efficacy of B7H3xCD3xPDL1 in humanized mouse models
3. Platform Versatility and Precision Prediction: Facilitating Clinical Translation
By replacing the targeting antigens, the team constructed HER2xCD3xPDL1 and CEAxCD3xPDL1 antibodies, which also effectively activated T cells and inhibited the growth of corresponding antigen-positive tumors, demonstrating the platform’s versatility.
Based on transcriptomic data and in vitro efficacy results from 33 patient samples, the team trained a machine learning prediction model. By identifying specific immune cell states (e.g., abundance of CD8⁺ cytotoxic T cells and memory T cells), the model achieved an AUC of 0.94 in predicting patient response rates, providing a tool for precise patient stratification in clinical settings.
IV. International Recognition and Research Significance: Pioneering a New Direction in Immunotherapy
In a concurrent commentary, renowned Spanish immunologist Pedro Berraondo and colleagues pointed out that this study creatively integrates tumor recognition and myeloid cell regulation via trispecific antibodies, proposing a novel engineering paradigm for overcoming immunosuppression in solid tumors and highlighting its pivotal role in next-generation tumor immunotherapy.
Core Significance of This Research
Breaking the bottleneck of “cold tumor” treatment It is the first study to achieve the synergistic effect of bystander T cell activation and immune microenvironment remodeling, providing an effective therapeutic strategy for solid tumors lacking tumor-specific T cells.
Enhancing therapeutic safety and efficacy The low-affinity CD3-binding domain design reduces off-target effects, and the local positive feedback loop avoids systemic cytokine storms, yielding high clinical translation potential.
Advancing precision immunotherapy The established machine learning model enables rapid screening of benefiting patients, avoiding ineffective treatment and reducing medical burdens.
Currently, this series of trispecific antibodies has laid the foundation for entering clinical research. In the future, it is expected to bring new survival hope to patients with various solid tumors such as ovarian cancer, colorectal cancer, and bladder cancer—especially those resistant to ICIs. The achievement of Professor Di Wen’s team not only demonstrates the original strength of Chinese scholars in the field of tumor immunotherapy but also provides a Chinese solution to the global challenge of solid tumor treatment.
Expert Profile
Professor Di Wen
Ren ji Hospital, Shanghai Jiao Tong University School of Medicine Chief Physician, Professor, Doctoral Supervisor, Director of the Shanghai Key Laboratory of Gynecologic Oncology
President, Chinese Medical Doctor Association Obstetrics and Gynecology Branch
Vice President, Chinese Medical Association Obstetrics and Gynecology Branch
President, Shanghai Medical Doctor Association Obstetrics and Gynecology Branch
Director, Shanghai Maternal and Infant Safety Expert Committee
Deputy Editor-in-Chief, Chinese Journal of Obstetrics and Gynecology; Deputy Editor-in-Chief, Chinese Journal of Practical Gynecology and Obstetrics and Shanghai Medical Journal; Editorial Board Member of multiple journals
As the first completed author, he has won the Second-Class Award of Science and Technology Progress of the Ministry of Education (2010), the Second-Class Award of Chinese Medical Science and Technology (2022), the First-Class Award of Shanghai Science and Technology Award (2022), the First-Class Award of Shanghai Medical Science and Technology Award (2018), the Second-Class Award of Shanghai Medical Award (2009), and the Third-Class Award of Shanghai Science and Technology Progress Award (2009).
Compiled textbooks have won the Special Award of Excellent Textbooks of Shanghai Jiao Tong University (12th Session, 2009), the Second-Class Award of Excellent Textbooks of Shanghai Colleges and Universities (2011), and the Excellent Textbook Award of Shanghai Colleges and Universities (2015).
Selected into the Shanghai Outstanding Academic Leader Program (2008); Winner of the Shanghai Leading Talent title (2011).
Winner of the “Good Doctor of China” title jointly awarded by the Central Civilization Office and the National Health Commission (2019); Winner of the “World Outstanding Chinese Physician Huo Ying dong Award” from the World Federation of Chinese Medical Doctors (2023).
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Content Review: Professor Di Wen’s Team