B-cell-specific MhcII regulates microbiota composition in a primarily IgA-independent manner

Major histocompatibility II (MHCII) mediated coordination of cellular interactions determines the capacity of an individual's adaptive immune response to serve as a force of natural selection regulating microbial ecology in the gut. However, despite representing the vast majority of MhcII expressing cells in secondary lymphoid organs, direct assessment of the role of B cell specific MhcII signaling in the regulation of microbial ecology in the gut has not been empirically defined. Here, we present the results of a novel adoptive transfer model that our lab developed in order to fill in this gap in our knowledge. Results from our experiments demonstrate that B cell specific MhcII regulates the phylogenetic composition, species abundance, and species richness of gut microbial communities and exerts its strongest effect in the small intestine.