Researchers at the Ragon Institute of Mass General Brigham, MIT, and Harvard have uncovered critical insights into how aging impairs the immune system’s ability to fight cancer. A study led by the Ringel Lab at the Ragon Institute and published in Cancer Immunology Research shows that as the body ages a type of immune cells called CD8+ T cells, essential for fighting tumors, become less effective — accelerating tumor growth and reducing the effectiveness of immunotherapy.

The study compared cancer growth in older and younger mice, revealing that tumors grow faster in aged mice due to weakened responses from CD8+ T cells. By analyzing the immune environment within tumors, the team identified a significant reduction in the presence of tumor-specific CD8+ T cells in older mice. This loss of critical immune cells was found to be a major factor driving both faster tumor progression and resistance to common immunotherapies like PD-1 blockade.

In a subsequent experiment, the researchers transferred antigen-specific T cells from young mice into older ones, resulting in delayed tumor growth and restored sensitivity to immunotherapy. These findings highlight the potential for developing treatments that address age-related declines in immune function and suggest that older patients may benefit from therapies that boost the effectiveness of their immune cells.

This research has important implications for the development of cancer treatments tailored to older patients and emphasizes the need to consider aging as a key factor in the design of pre-clinical cancer studies.