Parents, doctors, and researchers have long wondered how children who have greater exposure to potential pathogens seem to have less infections and less allergies. Living on a farm, playing in the dirt, and hand-washing dishes seem to strengthen kids’ immunity in a variety of immune studies. The idea that ongoing infectious or antigen stimulation keeps the immune system primed for bigger attacks has been dubbed the hygiene theory. Too much hygiene, meaning too clean of an environment, allows the immune system to weaken over time. This is also considered as a possible contributor to aging of the immune system in adults. Now we have at least one mechanism that explains this theory.
Researchers at the University of Arizona Health Sciences also recognized this connection and wanted to further apply such mechanisms in cancer therapies. They knew that a good supply of naive T cells correlated with better immune responses to infections. These immune cells arise from our bone marrow and then develop in our thymus gland. They serve our immune defenses in a variety of ways from directly killing cells already infected by an invader to coordinating the activities of other immune cells. Naïve T cells have not yet encountered an antigen and serve as a reserve for future microbial encounters.
As we age, the number of these naïve T cells fades unless they are stimulated. We originally thought stimulation only drove them to become memory T cells that persisted in fighting any return of the infection that triggered them. The current researchers found that the same infection stimulated the maintenance of adequate naïve T cells as well. With several experiments, they learned that the major histocompatibility complexes (MHC) and a cytokine called Interleukin-7 (IL-7) kept the naïve T cells alive and tuned up. Furthermore, another cytokine called interferon gamma synergized with the MHC and IL-7.
Functional MD’s like myself have known that a variety of mild immune stimulants serve to keep our immune system healthy. This reality is not news to us, but we do appreciate the news reporting on the mechanism by which this happens. Whether we encourage earthing practices or just getting out in nature, besides occasional real infections, keeping a healthy microbiome in gut, on our skin, and throughout out body keeps our immune system on alert for the real problem microbes. Living healthier more abundant lives means enjoying and benefitting from the world of nature gifted to us by our Creator.
Mladen Jergović, Christopher P. Coplen, Jennifer L. Uhrlaub, David G. Besselsen, Shu Cheng, Megan J. Smithey, Janko Nikolich-Žugich. Infection-induced type I interferons critically modulate the homeostasis and function of CD8 naïve T cells. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-25645-w
Thanks to Science Daily:
University of Arizona Health Sciences. “Researchers find surprising benefit to the immune system following infection.” ScienceDaily. ScienceDaily, 3 December 2021. <www.sciencedaily.com/releases/2021/12/211203151427.htm>.
Sanctuary Functional Medicine, under the direction of Dr Eric Potter, IFMCP MD, provides functional medicine services to Nashville, Middle Tennessee and beyond. We frequently treat patients from Kentucky, Alabama, Mississippi, Georgia, Ohio, Indiana, and more... offering the hope of healthier more abundant lives to those with chronic illness.