Immune Surveillance And Immune Evasion Of Senescent Cells
Our bodies are constantly working to maintain health, and a key part of this is the immune system’s ability to clear out problematic cells. Among these are “senescent cells,” which are cells that have stopped dividing but remain active, often accumulating as we age. While these cells can sometimes play beneficial roles, their buildup is linked to chronic inflammation and various age-related diseases, including cancer.
Normally, our immune system acts as a vigilant “surveillance” system, recognizing and eliminating these senescent cells to keep our tissues healthy. Immune cells like natural killer cells, T cells, and macrophages are crucial players in this process, identifying specific markers on the surface of senescent cells and targeting them for destruction.
However, senescent cells are not passive targets; they can develop clever strategies to “hide” from the immune system. They might change the markers on their surface, making them harder for immune cells to detect, or they can release signals that recruit “immunosuppressive cells”—immune cells that dampen the activity of other immune cells. They can also express “immune checkpoint molecules,” which are like “off switches” that tell immune cells not to attack, or they can interfere with “antigen presentation,” the process by which cells display fragments of proteins to alert the immune system.
When these evasion tactics succeed, senescent cells accumulate, contributing to the decline in immune function that often comes with aging, a process called “immunosenescence.” This accumulation further fuels chronic inflammation and tissue damage, accelerating the progression of age-related conditions. Understanding these intricate interactions between senescent cells and the immune system is crucial, as it opens doors for new therapeutic approaches that could boost the immune system’s ability to clear these cells, potentially preventing or treating a range of age-associated diseases.
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