How does the gut immune system know its microbial friends from its microbial foes?
Here on her site is a Belorussian translation of this page created by Martha Ruszkowski
host organism’s survival depends
critically upon getting the right answer: if a pathogenic microbe gets
for a commensal, immune responses will start too late—or not at all.
the opposite happens, the immune system will attack an innocuous
causing inflammatory damage—the situation thought to underlie
Janeway in 1989 proposed that microbial friends and foes
are distinguished by the use of pattern recognition receptors (PRRs)
detect molecular patterns associated with pathogens (PAMPs). The
Toll-like receptors (TLRs) in 1997 strikingly confirmed this approach.
molecules the only way that pathogens are recognized as distinct from
|Oddly, no one has yet discussed that mucosal immunity could also exploit the differences in microbial motility to intestinal epithelial cells (IEC). The gut wall obviously lacks the equivalent of “microscopes” that can directly observe microbial behavior to the IEC, but mucosal immunity can indirectly determine it by how it samples microbes from the lumen. The epithelium seeking motility of pathogens biases their catchment by “honey pot traps”, while commensals will tend to be immobile in the IEC adjacent biofilm.|
|Different kinds of microbe sampling can be therefore be biased to catch pathogens compared to commensals and vise versa. This need to have biased sampling I suggest in part explains why the mucosal immunity has evolved two different methods for obtaining microbes from the gut: M-cells (biased for sampling pathogens) and intraepithelial dendritic cell protrusions (biased for sampling commensals).|
Knowing gut friend from gut foe by gut sampling. 10,573 words 64 references
Outline of immunity pathogen/commensality classification by differential sampling, 1280 words
M-cells and knowing your microbial friends, talk UCL, Feb 16th, 2005 Powerpoint, 7.7 M 46 slidesFurther related ideas