The study shows that the immune system uses antibodies to communicate with the brain and trigger defensive responses against toxins and allergic reactions.
A new study by Yale researchers has revealed that the immune system plays a key role in shaping our behavior, especially when it comes to avoiding potential dangers in the environment. The study, published in the journal Nature, shows that the immune system uses antibodies to communicate with the brain and trigger defensive responses against toxins and allergic reactions.
The researchers, led by Ruslan Medzhitov, Sterling Professor of Immunobiology at Yale School of Medicine and investigator for the Howard Hughes Medical Institute, conducted experiments with mice that were allergic to a protein found in chicken eggs, called ova.
They found that these mice developed an aversion to water that contained ova, while normal mice preferred it. This aversion lasted for months and was mediated by a type of antibody called Immunoglobulin E (IgE), which is responsible for allergic reactions.
IgE antibodies bind to allergens and activate mast cells, which are immune cells that release chemicals such as histamine and serotonin. These chemicals then signal to the brain regions that control behavior, such as the amygdala and the hypothalamus, and induce avoidance of the allergen. The researchers showed that blocking IgE antibodies or mast cells prevented the mice from avoiding ova-laced water, indicating that the immune system was essential for this behavior.
The researchers also found that the immune system could learn from previous exposures to allergens and pathogens and memorize them for future avoidance. They showed that injecting mice with ova or a bacterial toxin could induce an aversion to water that contained either substance, even if the mice had never encountered them before. This suggested that the immune system could recognize potential threats and warn the brain about them.
Medzhitov said that the findings demonstrate how the immune system evolved to help animals cope with environmental challenges and avoid harmful ecological niches. He added that understanding how the immune system influences behavior could have implications for human health and disease, such as allergies, food poisoning, addiction, and mood disorders.
The future of the findings of the study may have implications for understanding and treating various disorders that involve altered behavior, such as anxiety, depression, autism, and addiction. It may also help us better cope with the challenges of living in a world full of pathogens and toxins, by learning how to modulate our immune responses and behavioral reactions.
Furthermore, this study may inspire more research on the interactions between the immune system and the nervous system, and how they influence each other in health and disease. This is a fascinating topic that could lead to major advances in the field of immunopsychology.
The study was supported by grants from the National Institutes of Health, the Howard Hughes Medical Institute, and the Blavatnik Family Foundation¹..