As we age, the immune system gradually declines in function, leaving the body more vulnerable to disease. Scientists have discovered a new way to rejuvenate a key component of immune function, potentially boosting health in later years.

A team from the Broad Institute of MIT and Harvard focused on the thymus, a small organ in front of the heart that’s crucial for the development of T cells. These immune cells act as guards, identifying and fighting threats such as cancer and infections.

From early adulthood, the thymus shrinks and slows, limiting T cell production. In mouse models, the researchers were able to repurpose part of the liver as a thymus substitute, sending the molecular signals that stimulate T-cell production.