title: Preparation and in vitro evaluation of imiquimod loaded polylactide-based micelles as potential vaccine adjuvants.
abstract: OBJECTIVE
  Activation of immune cells through pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) or NOD-like receptors (NLRs), has been identified as a key issue in the development of new efficient vaccine adjuvants. We report here on the elaboration and immunostimulatory potential of polylactide (PLA)-based micelles core-loaded with imiquimod TLR7 ligand and able to be further surface-functionalized with antigenic protein (HIV-1 Gag p24) for antigen delivery purpose.
  
  
  METHODS
  Micelles prepared from poly(D,L-lactide)-b-poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone) amphiphilic copolymer were incubated in the presence of imiquimod, leading to 1.2 wt% loading, and further conjugated to p24 antigen through reaction of p24 lysines and N-terminal amine with the N-succinimidyl pendant groups of the micelle corona. The impact of imiquimod encapsulation in the micelles on its immunostimulatory properties was investigated in vitro, by monitoring: (i) the NF-κB and mitogen-activated protein kinases (MAPK) pathways through experiments with RAW-Blue™ cells, a mouse macrophage cell line encoding an NF-κB/AP-1-inducible reporter construct; (ii) human dendritic cells (DCs) maturation markers by flow cytometry.
  
  
  RESULTS
  RAW-Blue™ cells based experiments showed that imiquimod encapsulated in the micelles was much more efficient to activate the NF-κB and MAPK pathways than free imiquimod. Furthermore, encapsulated imiquimod was found to induce much higher maturation of DCs than the free analog. Finally, these immunostimulatory properties of the loaded imiquimod were shown to be conserved when the p24 antigen was coupled at the micelle surface.
  
  
  CONCLUSIONS
  Taken together, these data regarding improved immunostimulatory efficiency suggest the strong potential of our micelle-based nano-system for vaccine delivery.
authors.affiliation: Université Lyon 1, CNRS, UMR 5305, Biologie Tissulaire et Ingénierie Thérapeutique, IBCP, 7 Passage du Vercors, 69367, Lyon Cedex 07, France.
authors.forename: Gloria
authors.initials: G
authors.lastname: Jiménez-Sánchez
authors.forename: Vincent
authors.initials: V
authors.lastname: Pavot
authors.forename: Christelle
authors.initials: C
authors.lastname: Chane-Haong
authors.forename: Nadège
authors.initials: N
authors.lastname: Handké
authors.forename: Céline
authors.initials: C
authors.lastname: Terrat
authors.forename: Didier
authors.initials: D
authors.lastname: Gigmes
authors.forename: Thomas
authors.initials: T
authors.lastname: Trimaille
authors.forename: Bernard
authors.initials: B
authors.lastname: Verrier
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D000634:Aminoquinolines / Q000008:administration & dosage* / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry*; D065546:Drug Liberation; D005434:Flow Cytometry; D016655:HIV Core Protein p24 / Q000276:immunology; D006801:Humans; D000077271:Imiquimod; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008823:Micelles; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D011205:Povidone / Q000031:analogs & derivatives* / Q000737:chemistry; D013499:Surface Properties; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D000276:Adjuvants, Immunologic; D000634:Aminoquinolines; D004337:Drug Carriers; D016655:HIV Core Protein p24; D008823:Micelles; D016328:NF-kappa B; D011091:Polyesters; D014612:Vaccines; C000601248:poly(lactide)-b-poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone); D020928:Mitogen-Activated Protein Kinases; D011205:Povidone; D000077271:Imiquimod