This is an interesting paper! Starting with a really big screen to look for GPCR activation by microbes, and ending with a convincing story by which microbes make acetylcholine in the gut to promote IgA production, ultimately leading to better colonization. www.nature.com/articles/s41...
nature.com
Commensal-derived acetylcholine enhances mucosal immune education - Nature
A diet–microbiome–host axis strengthens mucosal immune defences and reinforces host–microbiota mutualism.