title: β-Defensin 2 and 3 promote the uptake of self or CpG DNA, enhance IFN-α production by human plasmacytoid dendritic cells, and promote inflammation.
abstract: Alarmins are a group of structurally diverse host defense antimicrobial peptides that are important immune activators. In this article, we present a novel role for two potent alarmins, human β-defensin 2 and 3 (HBD2 and 3), in promoting IFN-α production by human plasmacytoid dendritic cells. We demonstrate that HBD2 and 3 activate pDCs by enhancing the intracellular uptake of CpG and self DNA and promote DNA-induced IFN-α production in a TLR9-dependent manner. Both CpG and host DNA form aggregates that resemble DNA nets when combined with HBD2 and 3. Isothermal titration calorimetry studies to elucidate the nature of HBD3/CpG complexes demonstrate involvement of enthalpy-driven interactions, in addition to hydrophobic interactions, with the formation of complexes at a molar ratio of 2:1 defensin/CpG. The i.v. administration of HBD3/CpG complexes induced proinflammatory cytokines like IL-12, IFN-γ, IL-6, IFN-α, and IL-10 in serum, associated with an increased recruitment of APCs in the spleen. Subcutaneous injections of these complexes showed enhanced infiltration of inflammatory cells at the injection site, indicating a potential pathophysiological role for alarmin/DNA complexes in contributing to inflammation. Intraperitoneal immunization of HBD3/CpG complexes with OVA enhanced both cellular and humoral responses to OVA, compared with OVA/HBD3 or OVA/CPG alone, indicative of a much more potent adjuvant effect of the HBD3/CpG complexes. Thus, the ability of defensins to enhance cellular uptake of nucleic acids can lead to improved vaccine formulations by promoting their uptake by various cells, resulting in an enhanced immune response.
authors.affiliation: Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Laboratory for Cancer Research, Frederick, MD 21702, USA. tewaryp@mail.nih.gov
authors.forename: Poonam
authors.initials: P
authors.lastname: Tewary
authors.forename: Gonzalo
authors.initials: G
authors.lastname: de la Rosa
authors.forename: Neeraj
authors.initials: N
authors.lastname: Sharma
authors.forename: Luis G
authors.initials: LG
authors.lastname: Rodriguez
authors.forename: Sergey G
authors.initials: SG
authors.lastname: Tarasov
authors.forename: O M Zack
authors.initials: OM
authors.lastname: Howard
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Shirota
authors.forename: Folkert
authors.initials: F
authors.lastname: Steinhagen
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Klinman
authors.forename: De
authors.initials: D
authors.lastname: Yang
authors.forename: Joost J
authors.initials: JJ
authors.lastname: Oppenheim
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D001692:Biological Transport; D002478:Cells, Cultured; D018899:CpG Islands; D004247:DNA / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007249:Inflammation / Q000276:immunology*; D016898:Interferon-alpha / Q000096:biosynthesis* / Q000097:blood; D007371:Interferon-gamma / Q000097:blood; D018664:Interleukin-12 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D051217:Toll-Like Receptor 9 / Q000378:metabolism; D023083:beta-Defensins / Q000378:metabolism*
chemical_list: D000276:Adjuvants, Immunologic; C422950:DEFB103A protein, human; C106641:DEFB4A protein, human; D016898:Interferon-alpha; D015850:Interleukin-6; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; D023083:beta-Defensins; D018664:Interleukin-12; D007371:Interferon-gamma; D010047:Ovalbumin; D004247:DNA