Newswise — New Haven, Conn. —Just the scent of seafood has the potential to cause severe illness in individuals allergic to it, leading them to be more inclined to steer clear. Similarly, those who experience food poisoning from a particular meal tend to display similar avoidance tendencies.
For quite some time, scientists have been aware of the crucial involvement of the immune system in our responses to allergens and environmental pathogens. However, it remained uncertain whether the immune system also influenced the development of avoidance behaviors towards allergic triggers.
According to Yale-led research published July 12 in the journal Nature, it turns out that the immune system plays a crucial role in changing our behaviors.
According to Ruslan Medzhitov, Sterling Professor of Immunobiology at Yale School of Medicine and senior author of the study, "We have discovered that immune recognition plays a role in regulating behavior, particularly defensive responses against toxins. This recognition process involves the production of antibodies that ultimately communicate with our brains." Medzhitov is also an investigator for the Howard Hughes Medical Institute.
The study demonstrates that without communication between the immune system and the brain, the body lacks the ability to receive warnings about potential dangers in the environment and consequently fails to initiate avoidance responses towards those threats.
In the Medzhitov lab, a team led by Esther Florsheim, who was a postdoctoral researcher at Yale at the time and is currently an assistant professor at Arizona State University, along with Nathaniel Bachtel, a graduate student at the School of Medicine, conducted a study using mice that were sensitized to exhibit allergic reactions to ova, a protein present in chicken eggs. The researchers observed that the sensitized mice displayed a tendency to avoid water containing ova, while the control mice showed a preference for ova-laced water sources. Notably, the aversion to ova-laced water persisted in the sensitized mice for several months.
Subsequently, the team explored the possibility of modifying the behavior of sensitized mice by manipulating immune system variables. Their investigations revealed that mice with an allergy to ova no longer exhibited aversion to the protein in their water when the production of Immunoglobulin E (IgE) antibodies, which are generated by the immune system, was blocked. IgE antibodies are responsible for triggering the release of mast cells, a specific type of white blood cell that, along with other immune system proteins, plays a crucial role in conveying information to the brain regions responsible for aversive behavior. By inhibiting IgE, the transmission of this information was disrupted, resulting in the mice no longer avoiding the allergen.
Medzhitov commented that the study's findings demonstrate the evolutionary role of the immune system in assisting animals in avoiding hazardous ecological environments. Furthermore, he noted that comprehending how the immune system stores information about potential dangers could potentially aid in the development of strategies to mitigate excessive reactions to various allergens and pathogens in the future.
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