Social status determines the immune system of rhesus monkeys
Social status obviously has a significant impact on the immune system. This is the conclusion reached by US researchers led by Jenny Tung from the Institute of Human Genetics at the University of Chicago when examining possible connections between the social rank of female rhesus monkeys and their immune systems.
As the US scientists report in the journal "Proceedings of the National Academy of Sciences" (PNAS), there is a direct connection between the rank of the rhesus monkey female and her immune system. At first glance, the conclusion is obvious that simply the females with the best immune system ranked highest. But the researchers led by Jenny Tung were able to prove that the change in social rank automatically changes the immune system. Accordingly, social status actually has a direct impact on the immune system. "Our results indicate that the social environment interferes with the genes and their activity," report the US scientists.
Unfavorable social environment increases risk of disease The researchers at the Institute of Human Genetics at the University of Chicago found that with an increasing number of female rhesus monkeys, the activity of the immune genes also increased. Conversely, this means that an "unfavorable social environment often leads to permanent physiological stress", the US scientists report. According to Jenny Tung and colleagues, the underlying "biological mechanisms are of great interest, both for understanding the evolutionary effects of social behavior and in the context of human health". In order to check the effect of the rank on the immune system, the researchers divided 49 rhesus monkey females into 10 social groups, "in which each individual social status could be controlled experimentally." In parallel, they examined the activity of certain genes in the animal organism in the laboratory . Tung and colleagues found that there was a strong causal relationship between social rank and gene regulation in primates. This connection was so clear that the state of the immune system made a relatively precise statement about the social status of the animals, the US researchers write. According to Jenny Tung and colleagues, the rank of the animals could be determined with 80 percent accuracy based solely on their genetic expression.
Different gene activity depending on the social rank To check whether the social rank actually determines the gene activity or the performance of the immune system and not vice versa, the gene activity decides the social rank, the US researchers had the rhesus monkey female several times between the groups exchanged, which also changed their social position. This change in social position was accompanied by an immediate adjustment of gene activity, report Tung and colleagues. "These shifts were short-term enough to be able to read the changes in rank of the females over time," the scientists write. According to the experts, the social position was clearly the trigger for these changes in the immune system. The gene activity determined on the basis of blood tests differed between the lower and higher-ranking rhesus monkey females in 987 genes, with the better-off females exhibiting a higher activity in 535 genes. These were primarily genes that were responsible for the production of T cells and other immune-boosting processes, report Tung and colleagues. The lower-ranking rhesus monkey females showed increased activity, especially in the genes that weaken the immune system, the US scientists continued. They produced fewer T cells and were significantly more susceptible to inflammation and infection, the researchers report.
Low social status means stress and weakens the immune system The US scientists said they found a clear link between the social status and the physiology of the rhesus monkey females, which could help “explain how social effects under the skin go, ”emphasized Jenny Tung. The researchers also deciphered how the altered gene activity is caused. It has been shown that certain areas of the genome of the female monkeys with a lower social status were blocked by hydrocarbon groups, which made reading for the cell machinery more difficult or prevented. This process, also known as methylation, is said to be one of the main mechanisms influencing the environmental effects on gene activity (epigentic effect), the US researchers write. For animals with a low social status, living in a strictly enforced hierarchy with little social support means chronic stress and a sustained weakening of the immune system. There are many indications that "the strain of social subordination triggers a physiological reaction", which causes a higher risk of illness, report Jenny Tung and colleagues. The associated biological mechanisms are also of great interest for human medicine, since conclusions about human health and social behavior are made possible, according to the conclusion of the US scientists in the article “Social environment is associated with gene regulatory variation in the rhesus macaque immune system ”. (fp)
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