The immunological Function of Mesenteric Lymph Node in Diet Induced Obesity

Obesity has emerged into a worldwide epidemic that is associated with cardiovascular disease, insulin resistance and probably intestinal inflammation. The mesenteric lymph nodes (mLN) are important for immune responses and acquisition of oral tolerance. However, the immunological status of mLN and their function in systemic inflammation after diet induced obesity is still unknown. Here we show that in a diet induced mouse model the cell subset composition in mLN change within 16-20 weeks. Analysis of the inflammatory response revealed that anti-inflammatory cytokines were reduced whereas pro-inflammatory cytokines such as IL-2 and IL-6 were increased. In addition, antigen specific immunoglobulines were induced. Although DNFB treatment as a model of allergic contact dermatitis showed no significant increased ear swelling in obese mice, mLN immune cells were strongly activated. This was characterized by increased homing on all lymphocyte populations.In summary, obesity resulted in mobilization of inflammatory cell subsets, an elevated level of pro-inflammatory cytokines and activated immune cells into mLN. These findings indicate a pivotal function of the mLN activating immune cells after diet induced obesity and provide new insights into the immunological mechanisms of obesity related systemic inflammation.