“In the wild, macaques inherit their social rank from their mothers” Tung said. “But in our research, the order of introduction determines rank; the newcomer is generally lower status. When some macaques’ status changed after a newcomer arrived, so did their patterns of immune system gene activity.”
To test how gene expression would differ when a monkey's rank changed, the scientists at Yerkes took the female macaques from their native groups and constructed 10 new social units, where rank was determined based on how early a female was added to her unit.
Tung and her collaborators then took blood samples from the monkeys and isolated the white blood cells. The results show that lower-ranking monkeys had lower levels of a certain kind of T cell and showed signs of exposure to chronic stress, two findings that helped explain why their genes turned on and off differently than high-ranking monkeys.
The researchers used microarrays to look at the macaques’ immune cells, a technology that allows them to scan thousands of genes and read the expression levels. The gene activity that changed the most depending on social rank was what controlled inflammation.
According to Dr. Tung the research is alarming in that a person’s social status can affect their immune system, but it also gives us hope in that we are not stuck at one place and that by making healthy changes we can change the expression of our genes and to healthier lives.
