GSE121811
Compartmentalized gut lymph node drainage dictates adaptive immune responses
Purpose: The intestine's main function is to digest and absorb dietary nutrients, with help from the absorptive epithelium and underlying vasculature and lymphatic system, as well as the microbiome. The intestine also houses the largest immune cell population in the body, tasked with providing resistance to toxins and invading pathogens while maintaining tolerance to dietary and microbial antigens, either by local action or lymphatic trafficking to the gut-draining lymph nodes (gLNs) to mount adaptive responses. While previous studies revealed the drainage map to various gLNs along the murine gut, and described immunological differences between gLNs, the underlying cellular components and the functional consequences of gut segment-specific drainage have not been systematically addressed. We sought to understand how compartmentalized lymphatic drainage of the intestinal milieu contributes to immune responses towards luminal antigens. Results: Here we report that gLNs are immunologically unique according to the functional gut segment they drain. Stromal and dendritic cell gene signatures, as well as adaptive T cell polarization against the same luminal antigen, differed between gLNs along the intestine, the proximal small intestine–draining gLNs preferentially giving rise to tolerogenic and the distal gLNs to pro-inflammatory T cell responses. This compartmentalized dichotomy could be perturbed by duodenal infection, surgical removal of select distal gLNs, dysbiosis, or ectopic antigen delivery, impacting both lymphoid organ and tissue immune responses. Conclusions: Our findings reveal that the conflict between tolerogenic and inflammatory adaptive responses is in part resolved by discrete gLN drainage, and encourage gut segment-specific antigen targeting for therapeutic immune modulation. Overall design: Sorted Dendritic cells from  Cecal-Colonic, Duodenum and Ileum Lymph Nodes in four different mice. Sorted Follicular and Lymphatic Endothelial cells from Cecal-Colonic, Duodenum and Ileum Lymph Nodes in three different mice.