Gut Microbiota Abrogates Anti-?-Gal IgA Response in Lungs and Protects against Experimental Aspergillus Infection in Poultry.
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ABSTRACT: Naturally occurring human antibodies (Abs) of the isotypes IgM and IgG and reactive to the galactose-?-1,3-galactose (?-Gal) epitope are associated with protection against infectious diseases, caused by pathogens expressing the glycan. Gut microbiota bacteria expressing ?-Gal regulate the immune response to this glycan in animals lacking endogenous ?-Gal. Here, we asked whether the production of anti-?-Gal Abs in response to microbiota stimulation in birds, confers protection against infection by Aspergillus fumigatus, a major fungal pathogen that expresses ?-Gal in its surface. We demonstrated that the oral administration of Escherichia coli O86:B7 strain, a bacterium with high ?-Gal content, reduces the occurrence of granulomas in lungs and protects turkeys from developing acute aspergillosis. Surprisingly, the protective effect of E. coli O86:B7 was not associated with an increase in circulating anti-?-Gal IgY levels, but with a striking reduction of anti-?-Gal IgA in the lungs of infected turkeys. Subcutaneous immunization against ?-Gal did not induce a significant reduction of lung anti-?-Gal IgA and failed to protect against an infectious challenge with A. fumigatus. Oral administration of E. coli O86:B7 was not associated with the upregulation of lung cytokines upon A. fumigatus infection. We concluded that the oral administration of bacteria expressing high levels of ?-Gal decreases the levels of lung anti-?-Gal IgA, which are mediators of inflammation and lung damage during acute aspergillosis.
SUBMITTER: Mateos-Hernandez L
PROVIDER: S-EPMC7350254 | biostudies-literature | 2020 Jun
REPOSITORIES: biostudies-literature
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