Posted on May 30, 2017, 6 a.m.
Using single-cell sequencing, researchers have shed light on a long-standing debate regarding why the immune system weakens with age.
Scientists may be close to understanding why our immune systems deteriorate with age. In a collaboration of European university and research institutions, team members have discovered that immune cells in older tissues lack coordination and show far more variability in gene expression in comparison with their younger counterparts. The study was published in the journal Science.
Parting from the traditional sequencing methods and their technological limitations, researchers used a technique called single-cell sequencing to analyze why the immune systems of older adults weaken with age. They studied CD4 cells (also called T-cells), which play a significant role in driving immune responses. In experiments on lab mice (both young and old), the researchers used single-cell sequencing to analyze the response of individual T-cells to stimulation.
Immune Cell Dysfunction May be Responsible for Aging
In aged animals, T-cells may still be strong but begin to lose their effectiveness due to a lack of coordination. On the other hand in younger animals, these cells are more tightly regulated making for a more effective immune system. The results of the study were replicated in immune cells of different types as well as on different species of mice. This is suggestive that increased cell-to-cell transcriptional variability could be a hallmark of aging throughout most mammalian tissues.
This study gives scientists new insight on how aging immune systems go astray. Armed with this knowledge, researchers can start to unravel the mysteries of how aging immune cell dysfunction takes place. The role of our immune system is to fight infections and cell abnormalities like cancer. However, understanding why our immune systems deteriorate with age is the first step to one day dramatically extending our lifespans with new anti-aging treatments.
Celia Pilar Martinez-Jimenez, Nils Eling, Hung-Chang Chen, Catalina A. Vallejos, Aleksandra A. Kolodziejczyk, Frances Connor, Lovorka Stojic, Timothy F. Rayner, Michael J. T. Stubbington, Sarah A. Teichmann, Maike de la Roche, John C. Marioni, Duncan T. Odom. Aging increases cell-to-cell transcriptional variability upon immune stimulation. Science, 2017; 355 (6332): 1433 DOI: 10.1126/science.aah4115