Because the strength of the immune system goes out of the ages

From: 21.02.2019 | Reading time: 3 minutes

GRib is particularly dangerous for the elderly, because the immune system has lost its influence over the years. Which protection mechanisms are affected in detail, scientists have now been examined in a study.

The immune system of the elderly responds more slowly and less fluctuating than the younger. As they grow older, the B cells that are critical to the immune response and the antibodies they produce no longer accumulate many mutations that ultimately allow the immune system to respond to a large number of different types of pathogens.

In particular, this means that the immune system can no longer respond to new viral variants as effectively as they are at a younger age, American researchers now report in CellHost & Microbe.

"The basic conclusion is that when newly infected influenza viruses infect the elderly, they may not have the proper tools to fight because their antibodies are not so protective," says Patrick Wilson, the University of Chicago study leader. our findings could be used by the vaccine community to improve vaccines and improve the protection of the elderly. "

Influenza viruses are constantly changing their shape, more specifically, microscopic features change on their surface. These very features recognize the immune system. It creates antibodies that attack these structures – thus destroying viruses. The vaccine is adjusted annually, as much as possible, to the types of current circulating viruses with their characteristic features.

The immune system responds to the constant changes in viruses, including a process called "physical hypermutation". The antibody genes of a mutant B cell, so that different antibody variants can ultimately be formed. The cells most capable of recognizing and fighting a virus are selected – they form the appropriate antibodies as required.

Among other things, scientists have explored how this process changes with age. It was compared how B cells from younger (22 to 64 years) and elderly adults (71 to 89 years of age) react when vaccinated with different influenza viruses.

B-cells of younger people have been shown to consistently accumulate mutations. At older age, this ability was reduced and the subjects had a somewhat variable B cell repertoire. Their antibodies were increasingly directed against the very conservative characteristics of the viruses. Therefore, they mainly responded to the historical variants of the virus that were released in the childhood of the subjects, the immune response to the newer variants of the virus was much weaker.

Vaccination remains the best protection against influenza, scientists say. "We are not saying people should not be vaccinated or that current vaccines are useless in the elderly," says researcher Carole Henry, who also works at the University of Chicago. The aim is rather to further improve vaccines.

The first variations, especially for the elderly, are already available. Such vaccines include special enhancers. However, there are still scientific studies in which the specific immune response to these vaccines should be investigated and demonstrated.

Decreasing efficacy of the immune system in old age is considered a central cause of illness and death, as resistance to bacteria, fungi and viruses disappears. The number of deaths from influenza illnesses varies greatly from year to year, with the disease being the most dangerous for over 60s.

The Standing Committee on Vaccination at the Berlin Robert Koch Institute (Stiko) therefore recommends vaccination against influenza especially for people aged 60 years and over. Even if the immune response is weaker for them, the elderly with a vaccine could already halve their risk of illness today. In addition, the disease is mild in vaccinated people.