title: Complement Component 3 Regulates IFN-α Production by Plasmacytoid Dendritic Cells following TLR7 Activation by a Plant Virus-like Nanoparticle.
abstract: The increasing use of plant viruses for the development of new vaccines and immunotherapy approaches poses questions regarding the mechanism by which the mammalian immune system recognizes these viruses. For example, although natural Abs (NA) and complement are key components of the innate immune system involved in the opsonization, phagocytosis, and destruction of microorganisms infecting mammals, their implication in plant virus recognition and immunogenicity is not well defined. In this study, we address the involvement of NA and the complement system in the activation of innate immunity through engagement of TLR7 with papaya mosaic virus (PapMV)-like nanoparticles. We demonstrate that NA, although binding to PapMV, are not involved in its recognition by the immune system. On the other hand, C3 strongly binds to PapMV nanoparticles and its depletion significantly reduces PapMV's interaction with immune cells. Unexpectedly, however, we observed increased immune cell activation following administration of PapMV to complement-depleted mice. TLR7 activation by PapMV in the absence of C3 induced higher IFN-α production, resulting in superior immune cell activation and increased immunotherapeutic properties. In conclusion, in this study we established the involvement of the complement system in the recognition and the phagocytosis of PapMV nanoparticles and identified an unsuspected role for C3 in regulating the production of IFN-α following TLR7 activation.
authors.affiliation: Immunovirology Laboratory, Institut national de la recherche scientifique (INRS), INRS-Institut Armand-Frappier, Laval, Quebec H7V 1B7, Canada.
authors.forename: Marie-Ève
authors.initials: MÈ
authors.lastname: Lebel
authors.affiliation: Immunovirology Laboratory, Institut national de la recherche scientifique (INRS), INRS-Institut Armand-Frappier, Laval, Quebec H7V 1B7, Canada.
authors.forename: Marie-Pierre
authors.identifier: 0000-0002-8701-3124
authors.initials: MP
authors.lastname: Langlois
authors.affiliation: Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, Quebec H1T 2M4, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Daudelin
authors.affiliation: Immunovirology Laboratory, Institut national de la recherche scientifique (INRS), INRS-Institut Armand-Frappier, Laval, Quebec H7V 1B7, Canada.
authors.forename: Esther
authors.initials: E
authors.lastname: Tarrab
authors.affiliation: Department of Molecular Biology, Medical Biology and Pathology, Laval University, Quebec City, Quebec G1V 4G2, Canada; and.
authors.forename: Pierre
authors.initials: P
authors.lastname: Savard
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Infectious Disease Research Centre, Laval University, Quebec City, Quebec G1V 4G2, Canada.
authors.forename: Denis
authors.initials: D
authors.lastname: Leclerc
authors.affiliation: Immunovirology Laboratory, Institut national de la recherche scientifique (INRS), INRS-Institut Armand-Frappier, Laval, Quebec H7V 1B7, Canada; alain.lamarre@iaf.inrs.ca.
authors.forename: Alain
authors.identifier: 0000-0002-7913-871X
authors.initials: A
authors.lastname: Lamarre
mesh_terms: D000818:Animals; D003176:Complement C3 / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D007371:Interferon-gamma / Q000096:biosynthesis*; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009029:Mosaic Viruses / Q000276:immunology*; D053758:Nanoparticles; D010587:Phagocytosis / Q000276:immunology; D016133:Polymerase Chain Reaction; D051199:Toll-Like Receptor 7 / Q000276:immunology* / Q000378:metabolism
chemical_list: D003176:Complement C3; D008562:Membrane Glycoproteins; C477038:Tlr7 protein, mouse; D051199:Toll-Like Receptor 7; D007371:Interferon-gamma