Investigators have discovered a population of tumor-fighting T cells that remain in the lymph nodes to provide protection against melanoma, according to a study published in Immunity. The investigators said that these cells, referred to as lymph node resident memory T cells, have been demonstrated to counteract the spread of melanoma in mice. They found that when mice that had previously been cured of cancer through immunotherapy had melanoma cells reintroduced, the lymph nodes remained resistant to the cancer.
“These T cells, for whatever reason, have changed their program and stay in the lymph nodes where they persist and kill tumor cells for many months while never entering circulation,” said Mary Jo Turk, PhD, co-director of the Immunology and Cancer Immunotherapy Research Program at Dartmouth’s and Dartmouth-Hitchcock’s Norris Cotton Cancer Center, in a press release. “We also identified T cells with similar characteristics in melanoma-invaded patient lymph nodes, showing that similar populations exist in humans,”
Although the concept of T cells taking up residence in lymph nodes has been previously documented, it has never been observed in cancer, according to the study. The investigators used innovative sequencing techniques to identify the unique transcriptional profile that makes these resident T cells specific to lymph nodes and to cancer. Computational analysis of melanoma specimen data found that the presence of resident T cells with this genetic signature was associated with better outcomes and improved survival for human melanoma patients who had lymph node metastases.
“We found that these cells have a unique gene expression profile that differentiates them from cells in circulation, and from memory T cells that reside in and protect other tissues such as the skin,” said Chao Cheng, PhD, in the release.
Future research is planned to investigate how to effectively generate and activate these memory T cells within the lymph nodes. According to the investigators, the ultimate goal of this research is to fully understand how memory T cells can be positioned throughout tissues to efficiently block the spread of cancer.
Researchers find immune cells that guard frequent site of cancer spread [news release]. EurekAlert; September 14, 2021. Accessed September 16, 2021. https://www.eurekalert.org/news-releases/927659