There’s a new therapeutic approach to boosting the weakened immune system that develops naturally with age, but it’s anything but conventional. A new study from the University of Arizona suggests that a virus can strengthen the immune system. For now, the research has been done in mice, but human clinical trials are not too far away.
The pathogen under the spotlight in the present study is cytomegalovirus (CMV), a common virus that affects people of all ages.
Once a person is infected, they are infected for life, but they usually show no signs or symptoms. Usually those who do develop symptoms as a result of CMV exposure are those people with weakened immune systems, including babies and the elderly.
"CMV doesn't usually cause outward symptoms, but we still have to live with it every day since there's no cure," explained one of the study’s leaders, Megan Smithey, PhD. "Our immune system always will be busy in the background dealing with this virus." In the new study, Smithey and her team infect old mice with CMV.
Their theory was that CMV would make the mice vulnerable to other infections because the virus was “using up resources and keeping the immune system busy.” Their study proved Smithey’s theory wrong.
Instead of weighing the mice down, CMV infection helped mice resist infection from listeria, a foodborne pathogen commonly present in improperly processed deli meats and unpasteurized milk products.
In addition to witnessing a stronger immune response to listeria as a result of CMV infection, after a closer look, researchers saw that the mice had a diverse supply of T cells, a population of cells vital to the adaptive immune response. Diversity in the T cell population indicates an increased ability to response to pathogenic invasions.
This finding challenges the long-held belief that T cell diversity decreases with age, leading to a weakened immune system. Instead, the researchers’ new hypothesis is that the T cell population is sustained throughout aging, but “recruiting them to the battlefield” becomes more difficult. In this case, CMV infection seemed to be the key to unlocking T cell power even in older populations.
Now researchers are launching a new study to uncover how CMV improves the immune system, with the hopes that they can harness this ability or even mimic it.
The present study was published in the journal Proceedings of the National Academy of Sciences.