Immune system can control your personality! You knew?

Human brains were designed for socialization. They have evolved to support and thrive on the complex interpersonal behaviors necessary for the survival of the species. Exactly how this happened is still unclear, but social neurologists generally believe that the benefits of peer bonds and two-parent parenting drove the process. In a curious twist, it now appears that germs may also have been involved. According to recent research, our immune system’s responses can directly control some aspects of our personality.

Immune system can control your personality! You knew?

In a study published in the journal Nature, neuroscientists at the University of Massachusetts Medical School and the Kipnis Laboratory at the University of Virginia School of Medicine discovered that they could control socialization behavior in mice by manipulating immune activity in the rodents’ brains.

To determine the social effects of deactivating a given immune response, researchers timed the time mice spent controlling each other under normal conditions and under conditions of immunodeficiency.

“Normal rats are very sociable and will always prefer to investigate another rat.” Revealed Jonathan Kipnis, co-author of the Nature article and president of the neurosciences department at UVA, in an email.

This inquisitive behavior changed when they genetically blocked the signaling pathways of a protein secreted by cells of the immune system to fight pathogens. Mice without them spent less time checking out other mice. When the researchers reopened the pathways, the mice returned to their normal levels of social interest.

To fully understand the significance of the discovery, it is useful to know that, until last year, science thought that the immune system did not reach the brain.

According to anatomy textbooks, the mammalian brain does not have lymphatics. The vessels that transport molecules that fight infections throughout most of the body.

In 2015, UVA scientists found the brain’s lymphatics. The news was revolutionary. For many, it was like finding a missing link.

Thus, immune activity can have profound impacts on the brain, as happens in multiple sclerosis, a brain disease caused by a malfunction of the immune system. And scientists have long observed a link between behavior and immunity. Brain disorders such as autism, Alzheimer’s disease and schizophrenia, which have strong behavioral components, present immune dysfunction. However, anxiety disorders and depression also have immune characteristics.

In the search for effective treatments, if immune dysfunction is a cause and not a symptom, that changes everything.

However, if immune activity also allows normal socialization, this could have dramatic implications for disease research. If the immune system has any control over how we socialize – a malfunction in the immune system can disrupt the brain activity that regulates healthy social behavior.