Defensin HNP-1 is a peptide secreted by polymorphonuclear leukocytes (PMNs) that has antimicrobial properties.1 It induces lysis of mammalian cells when used at concentrations of 25 and 100 μg/ml, respectively.2 It also completely inhibits secretion of the exotoxin superantigen TSS toxin-1 (TSST-1) from S. aureus when used at a concentration of 50 ng/ml and inhibits anthrax lethal toxin (IC50 = 148 nM).3,4 HNP-1 binds to recombinant HIV-1 envelope glycoprotein (gp120) and human CD4 (Kds = 23.2 and 12.9 nM, respectively).5 It induces lysis and leakage from liposomes composed of dipalmitoyl phosphatidylcholine and dioleyl phosphatidylserine (DOPS).6 In vivo, HNP-1 (5 μg) increases interferon α (IFN-α) production by human plasmacytoid dendritic cells (pDCs) injected into nude mice.7
1.Lehrer, R.I.Primate defensinsNat. Rev. Microbiol.2(9)727-738(2004) 2.Lichtenstein, A., Ganz, T., Selsted, M.E., et al.In vitro tumor cell cytolysis mediated by peptide defensins of human and rabbit granulocytesBlood68(6)1407-1410(1986) 3.Merriman, J.A., Nemeth, K.A., and Schlievert, P.M.Novel antimicrobial peptides that inhibit gram positive bacterial exotoxin synthesisPLoS One9(4)(2014) 4.Wei, G., Pazgier, M., De Leeuw, E., et al.Trp-26 imparts functional versatility to human α-defensin HNP1J. Biol. Chem.285(21)16275-16285(2010) 5.Wang, W., Owen, S.M., Rudolph, D.L., et al.Activity of ɑ- and θ-defensins against primary isolates of HIV-1J. Immunol.173(1)515-520(2004) 6.Fujii, G., Selsted, M.E., and Eisenberg, D.Defensins promote fusion and lysis of negatively charged membranesProtein Sci.2(8)1301-1312(1993) 7.Wang, F., Qiao, L., Lv, X., et al.Alarmin human α defensin HNP1 activates plasmacytoid dendritic cells by triggering NF-κB and IRF1 signaling pathwaysCytokine8353-60(2016)