CCR7 Engineering Guides Immune Cells to Precision-Kill Lymphoma Within Lymph Nodes

Chimeric Antigen Receptor T-cell (CAR-T) therapy has revolutionized the treatment landscape for hematologic malignancies. By reprogramming a patient’s own immune cells to recognize and attack tumor cells, this immunotherapy has delivered long-term remission and even cures for many patients. However, the therapy still frequently fails in many types of lymphoma—cancers that affect the lymphatic system—particularly when the malignant cells are nestled deep inside the lymph nodes.

While CAR-T therapy achieves an overall response rate of 50% to 80% in B-cell lymphomas, such as diffuse large B-cell lymphoma (DLBCL), a substantial proportion of patients still suffer from primary resistance or disease relapse. A critical reason for this is that lymphoma cells often hide deep within secondary lymphoid organs like lymph nodes and the spleen. During the ex vivo expansion process (growing cells outside the body), conventional CAR-T cells tend to downregulate key homing receptors, such as CCR7 and CD62L. Consequently, they lose their ability to infiltrate the lymph node parenchyma effectively, remaining trapped in the peripheral blood or the marginal zones of the spleen. Thus, no matter how potent the CAR-T cells are at killing tumor cells, it is futile if they cannot "find" the enemy.

Now, researchers led by Dr. Uta Höpken, head of the Microenvironment Regulation in Autoimmunity and Cancer Lab at the Max Delbrück Center, alongside former doctoral student Dr. Maria Zschummel, have found a way to help CAR-T cells reach their targets. By genetically engineering the cells to continuously express the receptor CCR7, the research team significantly enhanced their migration into the interior of lymph nodes, as well as their capacity to eradicate lymphoma cells. The breakthrough study was published in the journal Cancer Immunology Research.

"Many lymphomas grow primarily in the lymph nodes," explains Dr. Zschummel, who is now a postdoctoral fellow at Massachusetts General Hospital in Boston.

"If therapeutic immune cells cannot reach these specific niches effectively, even the most potent therapy can fail. By restoring the CCR7 receptor, we essentially provided the cells with a superior navigation system to locate the tumor."

Enhanced Homing and Rapid Clearance

"Under physiological conditions, immune cells utilize CCR7 to guide themselves into the lymph nodes," explains Dr. Höpken, whose laboratory has studied this receptor for many years. However, the standard manufacturing process used to produce CAR-T cells downregulates the expression of this receptor, thereby limiting the cells' ability to migrate into lymph node tissues.

To overcome this hurdle, the researchers modified the genetic engineering protocol for CAR-T cells so that they would permanently express CCR7. They then evaluated these modified cells across a suite of experiments using human immune cells, lymphoma cell lines, and mouse models of lymphoma.

They discovered that the engineered CAR-T-CCR7 cells successfully regained their ability to migrate into the lymph nodes, where they accumulated far more effectively. In mouse models, these cells cleared lymphoma cells with significantly higher efficiency than conventional CAR-T cells.

"This was a pleasant surprise," Dr. Zschummel says. "We initially expected only an improvement in migratory ability, but it turned out that CCR7 also simultaneously boosted the cells' killing efficiency."

A More Potent Immunotherapy

This work carries profound implications for oncology. Enhancing the ability of CAR-T cells to precisely pinpoint lymphoma cells promises to make the immunotherapy much more effective and could potentially lower cancer recurrence rates.

This homing strategy could also be applied to other malignancies that metastasize to the lymph nodes, adds Dr. Höpken, the senior author of the paper. "We have demonstrated that upgrading the 'navigation system' of immune cells makes them overall much more effective anti-cancer warriors."

She notes, however, that further research is required to evaluate the safety and long-term efficacy of this approach before it can be transitioned into clinical trials for patients. "Nonetheless, this work highlights how fundamental insights from basic immunology can be harnessed to refine next-generation cellular therapies."