Early host defence against pathogens -- at least in earthworms -- relies on communication between the nervous system and the intestine, suggests a paper online in Nature Immunology.
Previous studies conducted in other organisms indicated that signals from the nervous system can influence immune cells called lymphocytes, which act during later phases of immune responses.
Man-Wah Tan and Trupti Kawli now show that the worm nervous system is capable of modulating the very earliest, or innate, phase of the immune response against the human pathogen Pseudomonas aeruginosa. Cargo within vesicles released from the brain of worms infected with virulent -- or dangerous -- strains of this bacteria suppressed expression of anti-bacterial genes in intestinal cells. Avirulent -- or harmless -- strains of the bacteria did not trigger vesicle release, suggesting that bacteria targeted this system of brain-intestine communication to their advantage.
Whether these findings bear relevance to human host defence remains to be seen.
Man-Wah Tan (Stanford University, Stanford, CA, USA)
Abstract available online.
(C) Nature Immunology press release.
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