Here I'll post this on this thread as well:
Without the mucus in UC to prevent contact/protect perhaps the immune system just goes to town on the good guys. Or well, one could think of many different scenarios which could lead to dysbiosis and chronic infection.
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In regards to our bodies targeting of commensal bacteria during infection:
www.niaid.nih.gov/topics/autoimmune/research/Pages/gutMicrobiota.aspxOr this is the actual paper
www.sciencemag.org/content/337/6101/1553Results of Study - From the first link
To examine how the immune system responds to commensal bacteria before, during, and after infection, a study team led by Timothy Hand, Ph.D., and Yasmine Belkaid, Ph.D., in the Mucosal Immunology Section of the NIAID Laboratory of Parasitic Diseases, worked with mouse models of GI tract infection.
The team infected mice with the parasite Toxoplasma gondii, the cause of the disease toxoplasmosis. Specialized T cells in the mouse immune system cleared the parasite from the GI tract after nine days of infection. The team observed that nearly 10 percent of the T cells in the GI tract specifically attacked the parasite, but they also found that approximately
45 percent of the T cells responded to other gut microbes. This suggested that the specialized T cells may target commensal bacteria.
To focus their efforts, the team transferred immune cells from a mouse engineered to only make T cells that recognize Clostridium bacteria, a commensal that is associated with Crohn’s disease, into parasite-infected mice. The commensal-specific T cells rapidly divided in the infected mice and released a cell-signaling molecule that could target commensal bacteria. Additionally, these T cells remained in circulation after gut infection had been cleared, suggesting that they could mount a response to the commensal bacteria at a later time.
When the team transferred the commensal-specific T cells into uninfected mice, cell division and production of the cell-signaling molecule did not occur,
suggesting that the immune response to commensals occurs only during infection.---------
So it looks like during a GI infection our bodies target commensals to keep them in check or from becoming "opportunistic infectors" - but at the same time we make and distribute food rations (L-fructose bound to various protein molecules for them) to help them survive and feed during the immune invasion and some commercials change their gene expression during the war to differentiate themselves and say hey "I'm a good guy"... keep away from me please.
What was really interesting to me personally about
the above study was that "Infection" was required in order for the immune system to even target a commensal. Without in infection, the attack did not occur.
Post Edited (Canada Mark) : 1/10/2015 9:54:49 AM (GMT-7)