Stress and Immune System

The two arms of the immune system are in effect battling it out to dominate our mood.

[Immune System is the body셲 main function of defending itself against millions of antigens that would otherwise invade it.
None of these things will be able to affect the body when the immune system is working effectively. But the moment that the immune system stops functioning properly, the body becomes at risk of infection.]

weak immunity system-1What doesn셳 kill you makes you stronger, at least when it comes to stress and immune cells. Mice that received a cocktail of immune cells from bullied mice appeared to experience a mood boost. The unexpected discovery may have implications for treating depression.

We know that prolonged bouts of stress take their toll on the immune system. That leaves us susceptible to illness, which in some cases can lead to depression.

Most research on the link between immune health and mood has focused on the innate branch of the immune system the cells that mount the first response to pathogens, says Miles Herkenham at the National Institutes of Health in Bethesda, Maryland. His team wondered if there might also be a role for the adaptive branch of the immune system, which 쐋earns about a pathogen in order to respond rapidly the next time it appears.
To find out, the team introduced an aggressive competitor mouse into the cages of male mice. 쏷hese mice are like bullies, says he. Two weeks later, the bullied mice seemed depressed: they cowered in dark corners and seemed uninterested in the scent of a female.
The team extracted their adaptive immune cells and injected them into another set of mice bred to lack these cells. This meant that the recipient mice essentially acquired the adaptive immune system of the bullied ones.
If anything, he thought the recipients would become depressed, too. But the opposite happened: the cells appeared to have 쏿ntidepressant-like effects, he says.
The mice spent more time exploring open areas and were more interested in females compared to similar mice that didn셳 receive the injection (Journal of Neuroscience, DOI:10.1523/jneurosci.2278-14.2015).
stress

The team also injected the cells into a strain of mice known for their unresponsiveness. These mice are rarely used in research because they don셳 do anything they just sit in a corner. The mice were soon running around, exploring their surroundings with abandon. It was like a personality change. He thinks that adaptive immune cells may cope with stress by building up a sort of mood-boosting resilience, although he doesn셳 know how this happens. What셲 unclear is why the donor mice didn셳 eventually become better at coping with their bullies, and why chronically stressed people often have weak immune systems.
In these cases, the adaptive immune system appears to be held back from exerting its beneficial effects and the innate branch of the immune system may be to blame. It셲 already known that mice which receive a transplant of cells from the innate immune system can show symptoms of anxiety and depression. Perhaps the two arms of the immune system are in effect battling it out to dominate mood. George Slavich at the University of California, Los Angeles, says it would be premature to call the adaptive immune system 쏿ntidepressive. 쏷he immune system is extremely complex and these two branches interact in many ways, he says.
The team now hope to disentangle what is going on and explore whether reprogramming adaptive immune could hint at a new treatment for depression.

Source : New Scientist – January 31, 2015
see more: Miles Herkenham

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