Immune Tolerance: A Great New Study

The biome buzz these past few days was on research that shows that the same bacteria can cause different immune responses in different gut environments.[i]  For many years, Helicobactor bacteria have been associated with stomach ulcers.  It was always strange though, in that, most people (two-thirds of the world’s population, according to WebMD[ii]) have the species as a normal part of the biome.  Why then in some does it become problematic?

In this study, when it was introduced into healthy mice in a mostly germ-free environment, the immune system tolerated its presence just fine.  However, when it was introduced into mice that are genetically prone to developing colitis, the immune system regarded it as a threat and gut inflammation worsened.

“The study suggests that Helicobacter and similar bacteria labeled as “bad” may, in fact, be neutral or even beneficial, depending on the health of the individual. A person’s level of stress, poor diet or genetics all may influence the good or bad nature of gut bacteria, the scientists said.”

Immune tolerance is a key concept:  the idea that our bodies should be able to differentiate pathogens from the benign.  With our depleted biomes (not just the bacteria, of course, but the mycobiome, the macrobiome, etc), we’ve lost that tolerance. Really, you do have to wonder what would happen were these scientists to inoculate the mice prone to colitis with helminths, wait a few weeks, and see if the Helicobactor still caused increased inflammation.  Can increasing immune tolerance, via biome enrichment, counteract that tendency to hyper-react to neutral, or even benign, bacteria?

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[i] https://www.livescience.com/59900-gut-environment-affects-whether-bacteria-are-good-or-bad.html

[ii] http://www.webmd.com/digestive-disorders/h-pylori-helicobacter-pylori#1