Mayo Clinic Study Shows Immunotherapy Remodels Lymph Node Immune Environment

A new study from Mayo Clinic suggests that checkpoint immunotherapy may reshape the immune environment within lymph nodes after melanoma has spread to them. Researchers found that treatment reorganized several types of immune cells and changed the behavior of certain cells, called macrophages, that can either support or suppress an immune response depending on their environment. The study, published in Communications Biology, indicates that how immunotherapy reshapes the lymph node environment, rather than just how it affects individual immune cells, may be an important part of the body’s response to treatment. This preclinical research offers a broader perspective on why some patients benefit from these therapies while others do not.

Checkpoint immunotherapy helps the immune system recognize and attack cancer by blocking signals that can restrain immune cells. While these treatments have transformed cancer care, not all patients benefit, and researchers are working to understand why responses vary. The new findings suggest that the local environment in lymph nodes plays a critical role in determining treatment success. By examining the complex interactions between different cell types, the study highlights the need to look beyond T cells to understand the full scope of immunotherapy’s effects.

“We’re learning that treating cancer isn’t only about the T cells themselves. We also have to think about the environment they’re working in,” says Jessica Lancaster, Ph.D., senior author of the study and a Mayo Clinic immunologist. “Our study suggests that you may need to renovate the entire neighborhood to create an effective antitumor response.” This neighborhood includes the lymph nodes, which are organized hubs where immune cells interact and immune responses begin.

Using a preclinical model of melanoma metastasis, Mayo Clinic researchers studied lymph nodes that drain the area around a tumor following checkpoint immunotherapy. They combined advanced imaging with cellular and gene-expression analyses to examine which cells were present, where they were located and how they changed with treatment. The study builds on Mayo Clinic’s long-standing research into immune checkpoints, collaborating with Haidong Dong, M.D., Ph.D., whose earlier work contributed to understanding the checkpoint pathway targeted in this study.

Treatment reduced the amount of metastatic tumor in the lymph nodes and reorganized T cells, B cells, myeloid cells and cells that provide the lymph node’s structural framework. Researchers saw particularly notable changes in macrophages, immune cells that normally help clear damaged and dying cells but can be influenced by tumors to suppress the immune response. After checkpoint immunotherapy, macrophages showed signs of shifting toward a more immune-stimulating state. Researchers also observed greater physical separation between macrophages and T cells, which may reduce suppressive interactions that hinder the immune system’s ability to fight the cancer.

“For years, much of the focus has been on how these treatments help T cells attack cancer. What’s been missing from the big picture is the role of myeloid cells,” Dr. Dong says. “This study shows that these cells can also be reprogrammed to help stimulate the immune response against cancer.” The findings suggest that effective immunotherapy may depend not only on activating T cells but also on creating an environment where different immune cells can work together against cancer. This broader view of immunotherapy could influence how future therapies are designed to target the complex ecosystem of the lymph node.

“The lymph node is the site of immune activation,” Dr. Lancaster says. “Understanding what happens there could help us think differently about how to design therapies for different types of cancer.” The researchers caution that the study was conducted in a preclinical model and does not fully replicate how melanoma develops and spreads in people. Future studies will be needed to determine whether the same immune changes occur in patients and how they relate to treatment response. The research was supported by the National Institutes of Health, the Miltenyi Biotec Spatial Biology Award, and various Mayo Clinic cancer research programs.

Subject of Research: Impact of checkpoint immunotherapy on lymph node immune environment in melanoma metastasis

Article Title: Checkpoint immunotherapy reshapes immune environment in lymph nodes

Article References: Checkpoint immunotherapy reshapes immune environment in lymph nodes. Original publication (Bibliographic details unavailable.)

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Keywords: checkpoint immunotherapy, lymph nodes, melanoma, macrophages, immune response, Mayo Clinic, Communications Biology, preclinical model, cancer research, immune cells, Checkpoint, immunotherapy