Lpluncl acts as a novel candidate member of host defense compounds, playing an especially important role to recognize and eliminate bacteria, fungi and viruses in the oral cavity and upper airway.We hypothesize that Lpluncl can bind LPS, stimulate expression of related receptors and secretion of subsequent downstream cytokines.In vitro LPS binding assay was verified that Lpluncl protein shown stronger binding ability to LPS.But in bacteria colony formation and cell death assay experiments, Lplunc1 didn't express direct anti-bactericidal activity and can't induce cell apoptosis.