A new study in mice adds to the evidence suggesting that the immune system not only attacks invading pathogens but can also influence mood.
Over the past few years, scientists have discovered some intriguing links between immunity and the mind.
One of the immune signaling molecules, or cytokines, that mediates these links is called interleukin-17a (IL-17a).
IL-17a plays a role in psoriasis, which is an autoimmune skin condition, but it may also contribute to the depression that many people experience. Indeed, a study involving a mouse model of psoriasis found that IL-17a caused depression-like symptoms.
In humans, researchers have also linked the molecule to treatment resistant depression.
Research in mice has even implicated IL-17a in the development of autism.
The brain and the body are not as separate as people think, says Prof. Jonathan Kipnis, a neuroscientist at the Washington University School of Medicine in St Louis, MO.
While working at the University of Virginia School of Medicine in Charlottesville, Prof. Kipnis and colleagues found that IL-17a causes anxiety-like behavior in mice.
We are now looking into whether too much or too little of IL-17a could be linked to anxiety in people, says Prof. Kipnis.
The scientists have published the results of their mouse study in the journal Nature Immunology. Kalil Alves de Lima, a postdoctoral researcher who is also now at the University of Washington, led the research.
Immune cells called gamma-delta T cells produce IL-17a. The cells are present in the meninges, which are the membranes surrounding the brain and spinal cord.
To determine what effect IL-17a might have on behavior, the scientists studied mice whose gamma-delta T cells did not produce any IL-17a and mice who lacked the cells completely.
They put the mice through standard tests of memory, social behavior, foraging, and anxiety. The mice performed just as well as normal mice on all tests apart from two that measure anxiety levels.
In those tests, the mice who lacked gamma-delta T cells or did not produce any IL-17a were more likely to explore open areas. In the wild, this kind of behavior would put them at greater risk of being eaten by predators.
The researchers interpreted this as a sign of reduced anxiety in animals without IL-17a signaling in their central nervous system.
Next, the scientists investigated how the signal affects neurons in their brains. They found receptors for IL-17a on a type of stimulatory nerve cell called a glutamatergic neuron.
When they genetically manipulated the neurons to prevent them from making these receptors, the mice exhibited less anxiety-like behavior.
Previous animal research has revealed a multitude of possible links between bacteria living in the gut and behavior, including anxiety-like behaviors.
This connection is known as the gut-brain axis, and scientists have proposed the immune system as one possible way that messages pass between them.
To investigate the role of IL-17a in the gut-brain axis, Alves de Lima and colleagues injected the mice with lipopolysaccharide. This is a toxin that bacteria produce. It provokes a strong immune reaction.
In response to the injection, gamma-delta T cells in the meninges surrounding the animals brains produced more IL-17a.
In another experiment, when the researchers treated the mice with antibiotics to kill the bacteria in their guts, the animals produced less IL-17a.
Together, the results of these experiments suggest that the immune system has evolved not only to fight infection but also to adjust behavior to keep animals safe while they are in a weakened state.
Selecting special molecules to protect us immunologically and behaviorally at the same time is a smart way to protect against infection. This is a good example of how cytokines, which basically evolved to fight against pathogens, also are acting on the brain and modulating behavior.
Kalil Alves de Lima
The team is now investigating how gamma-delta T cells in the meninges surrounding the brain can detect the presence of bacteria elsewhere in the body.
The researchers are also looking into exactly how IL-17a signaling in the brain changes behavior.
In their paper, they conclude:
Our findings provide new insights into the neuroimmune interactions at the meningealbrain interface and support further research into new therapies for neuropsychiatric conditions.
Although the physiology of mice and humans is very similar, scientists need to carry out much more research to explore the possible links between the human immune system and mood.
Read the original:
Immune system may trigger anxiety in response to infection - Medical News Today
- Why Jews With Psoriasis Might Think Twice About Seeking Treatment in Jordan - December 20th, 2013 [December 20th, 2013]
- Skin conditions leave emotional scars - December 20th, 2013 [December 20th, 2013]
- Psoriasis Free Forever Review | How This Program Helps People Treat The Root Causes Of Their Psoriasis Symptoms ... - December 20th, 2013 [December 20th, 2013]
- Psoriasis | University of Maryland Medical Center - December 20th, 2013 [December 20th, 2013]
- Psoriasis Treatment, Symptoms, Pictures, Types, Prognosis ... - December 20th, 2013 [December 20th, 2013]
- Psoriasis - National Library of Medicine - PubMed Health - December 20th, 2013 [December 20th, 2013]
- Psoriasis: MedlinePlus - U.S. National Library of Medicine - December 20th, 2013 [December 20th, 2013]
- Psoriasis - Wikipedia, the free encyclopedia - December 20th, 2013 [December 20th, 2013]
- Psoriasis Symptoms, Treatment, Causes, Medication Information ... - December 21st, 2013 [December 21st, 2013]
- Psoriasis Free For Life Review - Watch This Before You Buy - Video - December 21st, 2013 [December 21st, 2013]
- Natural Psoriasis Relief in Seattle, Washington - Video - December 21st, 2013 [December 21st, 2013]
- PSORIASIS VULGARIS - Video - December 21st, 2013 [December 21st, 2013]
- Top 5 Powerful Home Remedies For Psoriasis - Video - December 21st, 2013 [December 21st, 2013]
- Psoriasis feedback after hijama - Video - December 21st, 2013 [December 21st, 2013]
- 9 Home Remedies For Scalp Psoriasis - Video - December 22nd, 2013 [December 22nd, 2013]
- Manga - Psoriasis - Video - December 22nd, 2013 [December 22nd, 2013]
- How to treat psoriasis | In Good Shape - Interview - Video - December 22nd, 2013 [December 22nd, 2013]
- Best Scalp Psoriasis Treatment - Video - December 22nd, 2013 [December 22nd, 2013]
- Sandoz begins Phase III clinical trial for biosimilar adalimumab - December 23rd, 2013 [December 23rd, 2013]
- Psoriasis - Wikipedia, la enciclopedia libre - December 23rd, 2013 [December 23rd, 2013]
- What Is Psoriasis? - December 23rd, 2013 [December 23rd, 2013]
- Psoriasis Treatment Medical Course - Video - December 23rd, 2013 [December 23rd, 2013]
- Healing Psoriasis Hypnosis Session - Video - December 23rd, 2013 [December 23rd, 2013]
- Natural Farm cure for Skin Problems like Psoriasis - Video - December 26th, 2013 [December 26th, 2013]
- Psoriasis - 100% Natural Treatment Shivax® - December 27th, 2013 [December 27th, 2013]
- Psoriasis Symptoms, Causes, Treatment - What is psoriasis ... - December 28th, 2013 [December 28th, 2013]
- 79 PSORIASIS SYMPTOMS HOMEOPATHY TREATMENT K N SRIDHAR P3 - Video - December 28th, 2013 [December 28th, 2013]
- 79 PSORIASIS SYMPTOMS HOMEOPATHY TREATMENT K N SRIDHAR P2 - Video - December 28th, 2013 [December 28th, 2013]
- 79 PSORIASIS SYMPTOMS HOMEOPATHY TREATMENT K N SRIDHAR P1 - Video - December 28th, 2013 [December 28th, 2013]
- Can Acupuncture treat psoriasis and other scalp disorders? - Video - December 28th, 2013 [December 28th, 2013]
- Psoriasis - Wikipédia - December 31st, 2013 [December 31st, 2013]
- Psoriatic nails - Wikipedia, the free encyclopedia - December 31st, 2013 [December 31st, 2013]
- How to Cure Psoriasis - Psoriasis Symptoms, Treatment, Causes, Medication Information - Video - December 31st, 2013 [December 31st, 2013]
- Psoriasis Chronicles - Dealing with Depression, Anxiety and Anger - Video - January 2nd, 2014 [January 2nd, 2014]
- How to Prevent Psoriasis Flare-Ups - January 4th, 2014 [January 4th, 2014]
- Psoriasis Treatment | Health Plus | Studio N - Video - January 4th, 2014 [January 4th, 2014]
- Ayurvedic Remedy for Psoriasis - By Panditha Elchuri - Video - January 4th, 2014 [January 4th, 2014]
- Silica Gel For Psoriasis / Neurodermatitis - Video - January 4th, 2014 [January 4th, 2014]
- comment traiter son psoriasis détail oubliés - Video - January 4th, 2014 [January 4th, 2014]
- Psoriasis tends to relapse after stopping Methotrexate, shown in a case at Life Force - Video - January 4th, 2014 [January 4th, 2014]
- hiking nevada Health and Wellness Enthusiast Dawn Talks About Managing Plaque Psoriasis hiking watch - Video - January 5th, 2014 [January 5th, 2014]
- Guttate psoriasis - Wikipedia, the free encyclopedia - January 7th, 2014 [January 7th, 2014]
- Biofeedback May Help Control Stress-Related Diseases - January 8th, 2014 [January 8th, 2014]
- Psoriasis can be managed with proper treatment - January 10th, 2014 [January 10th, 2014]
- CNN anchor: How I fight psoriasis - January 10th, 2014 [January 10th, 2014]
- Psoriasis - My Home Remedies - January 10th, 2014 [January 10th, 2014]
- Psoriasis: MedlinePlus en español - January 10th, 2014 [January 10th, 2014]
- Psoriatic arthritis - Wikipedia, the free encyclopedia - January 10th, 2014 [January 10th, 2014]
- CNN anchor Zain Verjee: How I fight psoriasis - January 11th, 2014 [January 11th, 2014]
- Testimonio psoriasis - Video - January 14th, 2014 [January 14th, 2014]
- Heroin addict with severe Psoriasis - Video - January 15th, 2014 [January 15th, 2014]
- biospray for Psoriasis - Video - January 15th, 2014 [January 15th, 2014]
- Psoriasis - Psoriasis Free For Life - Video - January 15th, 2014 [January 15th, 2014]
- 8 Cure For Scalp Psoriasis - Video - January 15th, 2014 [January 15th, 2014]
- Learn about plaque psoriasis, guttate psoriasis, inverse ... - January 16th, 2014 [January 16th, 2014]
- Psoriasis - Symptoms, Triggers, and Causes of Psoriasis on WebMD - January 16th, 2014 [January 16th, 2014]
- Psoriasis Causes, Symptoms, Treatments, Home Remedies - January 16th, 2014 [January 16th, 2014]
- Psoriasis Treatment - Dermasis Psoriasis Cream - My Honest Review - Video - January 16th, 2014 [January 16th, 2014]
- TV Commercial Psoriasis Speaks Couple Looking At Rings In Jewelery Store Emotional - Video - January 16th, 2014 [January 16th, 2014]
- TV Commercial Humira Psoriasis Medication Salon Clearer Skin is Possible - Video - January 16th, 2014 [January 16th, 2014]
- Psoriasis Symptoms, Causes and Treatment Pictures Slideshow - Video - January 16th, 2014 [January 16th, 2014]
- Psoriasis - Medscape Reference - January 19th, 2014 [January 19th, 2014]
- 5 Home Remedies For Scalp Psoriasis - Video - January 19th, 2014 [January 19th, 2014]
- Ikonsulta Mo: Medical Advise on Psoriasis - Video - January 19th, 2014 [January 19th, 2014]
- Patient Recruitment: Television Campaign for Severe Psoriasis - Video - January 23rd, 2014 [January 23rd, 2014]
- Patient Recruitment: Television Campaign for resistant, summertime Mild to Moderate Psoriasis - Video - January 23rd, 2014 [January 23rd, 2014]
- Dr stephen ferguson ND PhD chronic fatigue psoriasis cured - Video - January 23rd, 2014 [January 23rd, 2014]
- Noir Naturals Age of Innocence (Unscented) Goat's Milk Lotion for Psoriasis Relief - Video - January 23rd, 2014 [January 23rd, 2014]
- New biologic drugs offer relief for psoriasis sufferers - January 24th, 2014 [January 24th, 2014]
- Psoriasis traitement appliquer le lait pour le corps ISO UREA MD Vidéo La Roche Posay INFO PSO - Video - January 24th, 2014 [January 24th, 2014]
- Psoriasis - Video - January 24th, 2014 [January 24th, 2014]
- Coping with psoriasis - Video - January 26th, 2014 [January 26th, 2014]
- Exfoliative Dermatitis/Psoriasis Vulgaris with Psoriatic Arthritis with English Subtitles - Video - January 26th, 2014 [January 26th, 2014]
- Psoriasis skin care routine 2014 - Video - January 27th, 2014 [January 27th, 2014]
- How to treat psoriasis effectively - By Franziska Ringpfeil, Board Certified Dermatologist - Video - January 28th, 2014 [January 28th, 2014]
- My Psoriasis 411: Apple Cider Vinegar Tutorial for Scalp Treatment - Video - January 29th, 2014 [January 29th, 2014]
- 12 Best and Worst Foods for Psoriasis - January 31st, 2014 [January 31st, 2014]
- Psocial Psoriasis en radio Tagoror - Video - January 31st, 2014 [January 31st, 2014]
- Psocial Psoriasis en Canarias Hoy - Video - January 31st, 2014 [January 31st, 2014]
- Psoriasis Natural Treatment that Workswww savevid com - Video - January 31st, 2014 [January 31st, 2014]