Best known for keeping you physically healthy by fighting off disease-causing agents and by bolstering the body’s natural defenses, the immune system may also play a role in maintaining healthy social relationships, the University of Virginia School of Medicine has discovered.
In fact, as Dr. Jonathan Kipnis, the chairman of the UVA Department of Neuroscience, and his colleagues revealed in the journal Nature, they found that the immune system can directly affect, and in some cases control, social behaviors such as the desire to interact with one another.
Furthermore, they found that issues with the immune system could potentially prevent a person from having normal social interactions – a discovery that could significantly affect neurological conditions such as autism and schizophrenia, potentially leading to new treatment options.
“The brain and the adaptive immune system were thought to be isolated from each other,” Dr. Kipnis said in a statement, “and any immune activity in the brain was perceived as sign of a pathology. And now, not only are we showing that they are closely interacting, but some of our behavior traits might have evolved because of our immune response to pathogens.”
Your immune system could change your social ability.
Findings could lead to new treatments for autism, schizophrenia
While it might sound unbelievable, Dr. Kipnis, who last year revealed that the brain actually had a direct connection to the immune system, said that it might be possible that we are nothing more than “multicellular battlefields for two ancient forces: pathogens and the immune system. Part of our personality may actually be dictated by the immune system.”
In their new study, the UVA team demonstrated that a specific type of immune molecule called interferon gamma appeared to be essential for social behavior, and that several types of creatures, including mice, rats and flies, activate interferon gamma responses during such interactions. This is unusual, as the molecule is typically produced in response to bacteria, viruses or parasites.
When the researchers used genetic modification to block interferon gamma production in mice, portions of the rodents’ brains became hyperactive and the creatures were noticeably less social. When the molecule was restored, brain connectivity and behavior returned to normal, which led the researchers to conclude that it must play a “profound role” in normal social relationships.
“It’s extremely critical for an organism to be social for the survival of the species. It’s important for foraging, sexual reproduction, gathering, hunting,” said Dr. Anthony Filiano, lead author of the study and a Hartwell postdoctoral fellow in the Kipnis lab. “So the hypothesis is that when organisms come together, you have a higher propensity to spread infection.”
“So you need to be social, but [in doing so] you have a higher chance of spreading pathogens. The idea is that interferon gamma, in evolution, has been used as a more efficient way to both boost social behavior while boosting an anti-pathogen response,” he added. While he and his colleagues believe that it is unlikely that the molecule alone could cause or cure social problems associated with neurological and psychiatric disorders, their findings do suggest that the immune system could be one potential target for future clinical treatments.
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