[The intestinal flora: the scales without the sword].
The intestine is colonised by a vast population of resident bacteria which have established mutualistic relationships with their host throughout evolution, progressing from commensalism to symbiotic interactions. Intestinal bacteria benefit from resources available in their host, but reciprocally provide advantages to their host, by supplying enzymatic activities not encoded in the host genome, by promoting maturation of the intestine and of the gut associated immune system as well as by modifying the host metabolism. The commensal bacteria, although deprived of pathogenic attributes, might however become a danger for the host in case of translocation, acquisition of pathogenic features or via the inappropriate activation of intestinal inflammation. Remarkably, the commensal flora promotes the onset of innate and adaptive immune defences which, in turn, allow to set up a subtle balance between the host and the flora that promotes the symbiosis.
Bambou
Jean-Christophe
JC
INSERM EMI-0212, INSERM U571, Faculté de Médecine Necker-René Descartes, 156, rue de Vaugirard, 75730 Paris Cedex 15.
Giraud
Antoine
A
Gaboriau
Valérie
V
Taddei
François
F
Cerf-Bensussan
Nadine
N
D000328:Adult; D023181:Antimicrobial Cationic Peptides / Q000502:physiology; D001419:Bacteria / Q000201:enzymology / Q000276:immunology / Q000472:pathogenicity; D018407:Bacterial Physiological Phenomena; D018988:Bacterial Translocation; D018925:Chemokines / Q000378:metabolism; D002648:Child; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D019276:Glycocalyx / Q000502:physiology; D006706:Homeostasis; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007231:Infant, Newborn; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D007422:Intestines / Q000382:microbiology*; D016131:Lymphocyte Subsets / Q000276:immunology; D010581:Peyer's Patches / Q000276:immunology; D015163:Superinfection / Q000517:prevention & control; D013559:Symbiosis
D023181:Antimicrobial Cationic Peptides; D018925:Chemokines; D007070:Immunoglobulin A