Immune surveillance of senescent cells in aging and disease

Senescent cells are intrinsically immunogenic and can be eliminated by the immune system to facilitate tissue repair and regeneration. However, immune-mediated elimination is compromised with age, causing senescent cell accumulation in tissues, thus limiting healthspan and lifespan and promoting age-related diseases such as cancer. Here, we review how different components of the innate and adaptive immune systems, including natural killer cells, macrophages, neutrophils, dendritic cells, T cells and B cells, target senescent cells and how the intrinsic properties of senescent cells can lead to their escape from surveillance. We also discuss the phenomenon of senescence in immune cells themselves and how this affects the surveillance of senescent and cancerous cells. Finally, we touch on emerging therapeutic strategies to enhance the immunosurveillance of senescent cells, as understanding the molecular basis of senescence immunosurveillance and why its potency fails during aging may offer opportunities to treat senescence-mediated age-associated diseases and tissue dysfunction.