Short-term Fasting Enhances the Protection Against Listeria Monocytogenes Infection Through Changes of Intestinal CD103+ Dendritic Cells

Gastrointestinal tract is the first organ to be directly affected upon fasting. However, little is known about how the fasting influences intestinal immune system. In the present study, we focused on the changes of intestinal dendritic cells (DCs) in mice upon short-term fasting and how the changes influence protective immunity against Listeria monocytogenes (LM) infection. We found that the fasting induces an increased number of CD103+CD11b- DCs in both small intestinal lamina propria (SI LP) and mesenteric lymph nodes (mLN) and the SI LP CD103+CD11b- DCs undergo an active proliferation and migration by increased levels of GM-CSF and CCR7, respectively. At 24 hours post-infection (hpi) of LM, there was a significant reduction of bacterial burden from the spleen, liver, and mLN of the short-term fasting mice compared to those of ad libitum mice. Accordingly, short-term fasting mice showed enhanced survival against LM infection when compared with ad libitum mice. Furthermore, significantly high amount of TGF-β2 and Aldh1a2 expression from CD103+CD11b- DCs in mouse infected with LM sequentially caused the following events: the increase of Foxp3+ Tregs, preferential change in the composition of CD103+ to CD103- DCs, and the induction of IFN-γ producing cells. Collectively, increase of intestinal CD103+ DCs by short-term fasting is a key player for protection against LM infection through the changes of functional features from tolerogenic to Th1 immunogenic.