Rhythmicity of Intestinal IgA Responses Confers Oscillatory Commensal Microbiota Mutualism. undefined

Interactions between the mammalian host and commensal microbiota are enforced through a range of immune responses that confer metabolic benefits and promote tissue health and homeostasis. Immunoglobulin (Ig)A responses directly determine the composition of commensal species that colonize the intestinal tract but require significant metabolic resources to fuel antibody production by tissue-resident plasma cells. Here we demonstrate IgA responses are subject to diurnal regulation by dietary-derived metabolic cues and a cell-intrinsic circadian clock. Reciprocal interactions between the host and microbiota conferred rhythmicity in IgA secretion, which in turn dictated oscillatory patterns on the commensal microbial community and its associated metabolic activity, resulting in changes to metabolite availability over the course of the circadian day. Our findings suggest circadian networks comprising intestinal IgA, the diet and the microbiota align to ensure host-microbial mutualism.