Effect of Leptin on Neutrophils Phagocytosis and Lymphocytes Apoptosis Challenge by Listeria monocytogenes and Escherichia coli

Background: Leptin is a cytokine/hormone produced mainly by the adipocytes which regulates the body weight. The normal level of Leptin is required for optimal immune system function, and high leptin levels are shown to affect the Thl-Th2 balance. Leptin is able to stimulate monocytes, dendritic cells and Neutrophils. Objectives: The aim of this study was to evaluate the effect of leptin on neutrophils phagocytosis and lymphocytes apoptosis stimulated byListeria monocytogenes and Escherichia coli. Materials and methods: Blood samples were taken from healthy volunteers and were treated with either leptin or PBS in presence or absence of L. monocytogenes or E. coli. In order to evaluate the activation of neutrophils and their phagocytosis activity, the expression of CD11b by these cells were assessed using flow cytometry. The ability of leptin to induce apoptosis in lymphocytes was investigated using Annexin V and PI staining method by flow cytometry. Results: Our data demonstrates that leptin is able to induce CD11b expression on neutrophils but this induction is significantly less than L. monocytogenes. Indeed, cells treated with leptin had lower amounts of apoptosis compared with untreated cells. The highest amount of apoptosis was seen in cells treated with L. monocytogenes vs. E. coli. Leptin can be used as a potent agent for induction of effective bacterial phagocytosis and lymphocytic apoptosis in cases with sever immune-deficiency. Conclusions: The Leptin can also be used for the treatment of severe and intractable L. monocytogenes and E. coli infection.