The virus helps immunity
The body's immune system works as efficiently as possible at a young age, and it weakens closer to old age – it becomes increasingly difficult for the body to fight infections. That is why older people are more susceptible to various diseases.
In search of a way to "rejuvenate" the immune system in the elderly, researchers from the University of Arizona Center on Aging found that one particular virus not only does not weaken, but actually strengthens it.
We are talking about the human herpes virus type 5 (cytomegalovirus, CMV), the carriers of which are more than half of all mankind. It enters the body at a young age and, since there is no specific treatment, it remains there for life. As a rule, CMV does not manifest itself in any way, but this does not mean that it is inactive – the immune system is constantly fighting it in the "background".
Previous epidemiological studies have shown a correlation between CMV and aging of the immune system, especially in old age. It remained unclear whether CMV is a key factor or simply accompanies the aging process of the immune system.
To find out what effect this virus has on the immunity of an elderly organism, scientists infected mice with CMV. They assumed that this would make mice less resistant to other pathogens, since the body has to spend part of its immune resources on suppressing CMV. But that didn't happen. When infected with listeria, old mice carrying CMV were ill in a less severe form than mice without CMV.
Researchers have yet to figure out exactly how the presence of the virus leads to an increased immune response. But it is already obvious that the immunity of an elderly organism has more potential than is commonly believed.
The researchers analyzed the number of key participants in the immune response and found that both groups of old mice had a decent supply of various T-lymphocytes.
It is believed that the diversity of lymphocytes decreases with age, and this is one of the reasons for the high incidence among the elderly. But the results of the study show that in old mice, the number and diversity of T cells almost do not differ from that in young ones. As it turned out, the problem is different: lymphocytes migrate in insufficient numbers to the infection zone. Unless old mice are infected with CMV.
Thus, an elderly organism is able to generate a good immune response, and CMV, more precisely, the body's reaction to it, helps to use this ability.
These data contradict the hypothesis that CMV has an exceptionally negative effect on the immune system, accelerating the aging process.
The authors plan to continue studying CMV. They hope to get confirmation of their results in human studies. The ultimate goal of the team is to create a vaccine that could "rejuvenate" the immune system of the elderly.
Article by M. J. Smithey et al. Lifelong CMV infection improves immune defense in old mice by broadening the mobilized TCR repertoire against third-party infection published in the journal PNAS.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Arizona: This Virus Actually May Boost — Not Weaken — Our Immune System.