AUTHOR=Wyss Madeleine , Brown Kirsty , Thomson Carolyn A. , Koegler Mia , Terra Fernanda , Fan Vina , Ronchi Francesca , Bihan Dominique , Lewis Ian , Geuking Markus B. , McCoy Kathy D. TITLE=Using Precisely Defined in vivo Microbiotas to Understand Microbial Regulation of IgE JOURNAL=Frontiers in Immunology VOLUME=10 YEAR=2020 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.03107 DOI=10.3389/fimmu.2019.03107 ISSN=1664-3224 ABSTRACT=

Early life exposure to microbes plays an important role in immune system development. Germ-free mice, or mice colonized with a low-diversity microbiota, exhibit high serum IgE levels. An increase in microbial richness, providing it occurs in a critical developmental window early in life, leads to inhibition of this hygiene-induced IgE. However, whether this inhibition is dependent solely on certain microbial species, or is an additive effect of microbial richness, remains to be determined. Here we report that mice colonized with a combination of bacterial species with specific characteristics is required to inhibit IgE levels. These defined characteristics include the presence in early life, acetate production and immunogenicity reflected by induction of IgA. Suppression of IgE did not correlate with production of the short chain fatty acids propionate and butyrate, or induction of peripherally induced Tregs in mucosal tissues. Thus, inhibition of IgE induction can be mediated by specific microbes and their associated metabolic pathways and immunogenic properties.