Here’s what you need to know
Immune cells in your gut could be causing your stress-induced depression according to a new study from researchers at John Hopkins Medicine. Luckily, the discovery may also provide doctors and psychiatrists with a new way to treat complex mental illnesses.
Keeping the human body in balance![]()
Doctors have long understood that our immune system works in collaboration with our gut microbiome to keep the human body in balance according to the team of researchers from John Hopkins Medicine.
Stress can affect the body and brain
Unfortunately, the process of keeping our bodies in balance can also have unintended consequences—a prime example of which is how our response to stress can affect the body and brain.
“Stress alters the microbiome composition”![]()
“Stress alters the microbiome composition, leading to impaired brain function,” the John Hopkins researchers wrote in their study, conceding, however, that “how the intestinal immune system mediates these effects remains elusive,” at least until now.
Immune cells can impact the gut microbiome
According to a press release from John Hopkins, researchers found during mice and human experiments that a particular type of immune cell found in their subject’s bodies had a significant and specific impact on their gut microbiome, which in turn affected their levels of social avoidance.
Gamma delt T cells![]()
“The results of our study highlight the previously unrecognized role of intestinal gamma delta T cells (γδ T cells) in modifying psychological stress responses,” said Dr. Atsushi Kamiya, one of the senior authors of the study.
The key to helping stress-induced disorders
Luckily, the discovery that gamma delta T cells could affect our mental health not only added to our scientific understanding of complex psychological disorders but also provided doctors and researchers with a potential new avenue for providing solutions.
Targeting stress reactions in the gut![]()
In their study, the researchers noted that if doctors could target the changes being made by immune cells in the gut with drugs or other therapies, it could provide our world with a new and more effective means of treating depression and social avoidance behaviors.
The dectin-1 receptor
Dr. Kamiya identified dectin-1, a protein receptor found on the surface of gamma delta T cells, as being of particular importance for developing future gut-related depression treatments since it appeared to regulate stress-induced behaviors in test subjects.
Activating immune cells in specific ways![]()
“Dectin-1 binds to certain antigens, or proteins, to signal immune cells to activate in specific ways,” the John Hopkins press release read.
Altering the gut microbiome 
“This receptor, the researchers say, may be involved in the microbiome alteration and immune-inflammatory responses in the colon of mice,” the press release added.
More gamma delta T cells increases social avoidance![]()
Dr. Xiaolei Zhu was the lead author of the study and explained that their research showed how stress would increase the number of gamma delta T cells in their rodent test subjects, which would then lead to an increase in their social avoidance behavior.
Adding Lactobacillus johnsonii 
However, social avoidance decreased and gamma delta T cell levels returned to normal if the test subjects were given a type of probiotic bacteria known as Lactobacillus johnsonii, something Zhu suggests may mean stress-induced behavior is the result of lower levels of good bacteria in the gut.
Lactobacillus could influence depression![]()
“Despite the differences of intestinal microbiota between mice and humans, the results of our study indicate that the amount of Lactobacillus in the gut may potentially influence stress responses and the onset of depression and anxiety,” Dr. Kamiya explained.
Supplementation could be the key
“These early-stage findings show that in addition to probiotic supplements, targeting drugs to such types of receptors in the gut immune system may potentially yield novel approaches to prevent and treat stress-induced psychiatric symptoms such as depression,” Kamiya added.
More research is needed![]()
