Mesenteric lymph nodes at the center of immune anatomy.

The surface of the intestinal mucosa is constantly assaulted by food antigens and enormous numbers of commensal microbes and their products, which are sampled by dendritic cells (DCs). Recent work shows that the mesenteric lymph nodes (MLNs) are the key site for tolerance induction to food proteins and that they also act as a firewall to prevent live commensal intestinal bacteria from penetrating the systemic immune system.