In a groundbreaking advancement spearheaded by scientists at the University of Maryland School of Medicine, new insights into CAR T-cell therapy reveal a promising target to bolster the efficacy of this revolutionary cancer treatment. Despite the remarkable success of CAR T-cells—immune cells genetically engineered to seek and destroy cancer—clinical relapse within five years remains a formidable challenge for patients battling recurrent and treatment-resistant blood malignancies. The latest research identifies a molecular mechanism by which CAR T-cells inadvertently diminish their own potency, offering innovative pathways to extend their tumoricidal potential.
CAR T-cell therapy fundamentally transforms a patient’s own immune system by reprogramming T-cells to express chimeric antigen receptors (CARs), specialized proteins that recognize cancer cells and initiate immune attacks. While many patients experience significant remission following this treatment, the persistence and sustained activity of CAR T-cells are critical for long-term success. Researchers at UMSOM uncovered a sophisticated cellular interaction which compromises this durability: CAR T-cells strip fragments of target antigens from the surface of tumor cells and subsequently integrate those fragments onto themselves, a process known as trogocytosis.
This phenomenon, meticulously elucidated by Dr. Kenneth Dietze and colleagues, reveals that trogocytosis effectively masks CAR T-cells, causing them to misidentify themselves as cancer cells. This self-marking diminishes their ability to continuously recognize and attack tumor populations, thereby reducing the therapeutic window. By visualizing this interaction with state-of-the-art lattice light sheet microscopy—providing unprecedented three-dimensional, real-time imagery—the scientists captured CAR T-cells actively tearing membrane patches from malignant cells, highlighting an unexpected cellular tug-of-war.
Central to this process is the lysosomal enzyme cathepsin B, which the research team identified as a key mediator of trogocytosis. Cathepsin B facilitates the detachment and transfer of antigen fragments during the immune synapse formed between CAR T-cells and cancer targets. Crucially, inhibiting cathepsin B activity curtailed the trogocytosis process, preserving CAR T-cell functionality and enhancing their cytotoxic persistence in preclinical models. These findings illuminate a critical checkpoint in CAR T-cell exhaustion and open exciting prospects for enhancing immunotherapy durability.
The implications of this study are profound. By pharmacologically targeting cathepsin B, it may be possible to develop adjunct therapies that sustain CAR T-cell potency, extending remission durations and limiting relapse rates among patients with hematologic cancers such as B-cell lymphomas. The comprehensive approach of combining molecular biology, advanced imaging, and immunotherapy positions this discovery at the forefront of translational cancer research, priming it for eventual clinical application.
Dr. Tim Luetkens, Associate Professor of Microbiology and Immunology and senior author, emphasizes that while genetically engineered immune cells are a transforming frontier in oncology, their nuanced biology remains incompletely understood. This work represents a vital stride toward decoding and manipulating the subtle intercellular dynamics that dictate therapeutic outcomes. It underlines the necessity of integrating detailed mechanistic studies with cutting-edge treatment modalities to improve patient survival.
Moreover, the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center’s ongoing clinical trials harness CAR T-cell technology for patients whose cancers prove particularly recalcitrant. By integrating this novel cathepsin B inhibition strategy, forthcoming trials may see unprecedented success rates and durable responses. The Center’s multidisciplinary expertise in cancer immunology, combined with its collaborative efforts with the University of Maryland College Park’s Upadhyaya lab—pioneers in optical imaging—signal a new era of precision immunotherapy.
In addition to advancing scientific understanding, this research exemplifies the power of multidisciplinary collaboration. The employment of lattice light sheet microscopy, developed by Dr. Arpita Upadhyaya’s team, enabled the unprecedented visualization of immune cell behavior, providing both qualitative and quantitative data crucial for validating the functional role of cathepsin B in live-cell interactions. Such technical innovation underscores how technological advances catalyze breakthroughs in biomedical research.
Financial backing from prominent institutions including the Maryland Department of Health, the National Cancer Institute, and the American Cancer Society highlights the recognition of this research’s transformative potential. Their support facilitates complex investigations into immune cell biology and therapeutic innovation, reinforcing the critical role of sustained funding in combating cancer through emerging immunological strategies.
Ultimately, the discovery that inhibiting cathepsin B can prevent trogocytosis marks an essential milestone in improving CAR T-cell therapy’s longevity and effectiveness. This strategy promises a paradigm shift in treating not only blood cancers but potentially other malignancies amenable to cell-based immunotherapies. As the scientific community eagerly awaits human clinical trials, the integration of this molecular insight into therapeutic design offers new hope for durable cancer remissions and improved patient quality of life.
The research by Dr. Luetkens, Dr. Dietze, and their collaborators illustrates the intricate dance between immune system mechanics and cancer cells, revealing vulnerabilities that can be exploited for therapeutic gain. It is a testament to the evolving landscape of cancer immunotherapy, where precision targeting at the cellular and molecular level transforms the outcomes for patients facing some of the most challenging malignancies.
The University of Maryland’s commitment to pioneering cancer research, clinical innovation, and the seamless integration of imaging technologies continues to position it among the nation’s top cancer centers. This breakthrough holds promise not only for enhancing CAR T-cell function but also for inspiring new approaches to immune modulation that will reshape cancer treatment paradigms globally.
Subject of Research: Animals
Article Title: Preventing trogocytosis by cathepsin B inhibition augments CAR T-cell function
News Publication Date: 22-Apr-2026
Web References: https://www.nature.com/articles/s41392-026-02654-z, https://www.umms.org/umgccc/news/2024/umgccc-car-t-cell-therapy
References: 10.1038/s41392-026-02654-z
Image Credits: University of Maryland School of Medicine
Keywords: Cancer immunotherapy, Chimeric antigen receptors, Blood cancer
