How periodic calorie restriction bolsters the immune system
Immune system cells called memory T cells help fight off invaders that have infiltrated the body once before. In order to do this, these T cells must survive long term. Learning how T cells withstand periods of food scarcity when nutrients are in short supply is critical to understanding how the human immune system functions in resource-poor environments and could also suggest strategies to boost its ability to combat disease.
IRP investigators, led by Yasmine Belkaid, Ph.D., showed that memory T cells become much more abundant within the bone marrow during periods of calorie restriction, even while their numbers collapse in other organs such as the lymph nodes and spleen. This happens because the T cells in the bone marrow go into a state of energy conservation. Furthermore, movement of memory T cells to the bone marrow caused profound changes in that tissue, including increased red blood cell and fat cell production. Calorie restriction was also associated with greater protection against infections and tumors in mice.
This research revealed a fundamental way that the body sustains and optimizes the strength of the immune system when food is scarce, thereby increasing the odds of surviving disease. The work also raises the possibility that nutritional interventions such as periodically restricting energy intake through intermittent fasting or similar methods may support memory T cells’ ability to protect against infection or cancer.
Collins N, Han SJ, Enamorado M, Link VM, Huang B, Moseman EA, Kishton RJ, Shannon JP, Dixit D, Schwab SR, Hickman HD, Restifo NP, McGavern DB, Schwartzberg PL, Belkaid Y. (2019). The Bone Marrow Protects and Optimizes Immunological Memory during Dietary Restriction. Cell. Aug 22;178(5):1088-1101.e15.