**7. Leptin and pathogenesis**

Leptin does not only imply energy homeostasis but also extends its regulatory function at infectious conditions. But the contagious status regulation mode of leptin is the least explored signaling mechanism. Latest research support that leptin could activate phagocytosis of macrophages and could secure the immune cells from pathogenic infections [63]. In *Klebsiella pneumonia* infection, exogenous administration of leptin shows CD11b dependent phagocytosis [64]. It protects lymphocyte deficient mice from various conditions [65]. Several studies have strongly highlighted the therapeutic application of the molecule to innervate infectious diseases, including AIDS [66].
