In the present study, following rt-hLEP infection, some differentially expressed genes were associated with “PPAR signaling pathway”, including PPARα, PPARγ, CYP8B1, ACOX1, ACBP, FATCD36, UBC and PDK1, suggesting the leptin-induced activation of fatty acid β-oxidation through, at least in part, PPAR signaling pathway. The gene discussed is CYP8B1; the disease is infection.