title: Gold nanoparticle-M2e conjugate coformulated with CpG induces protective immunity against influenza A virus.
abstract: OBJECTIVE
  This study aimed to develop a novel influenza A vaccine by conjugating the highly conserved extracellular region of the matrix 2 protein (M2e) of influenza A virus to gold nanoparticles (AuNPs) and to test the vaccine in a mouse influenza challenge model.
  
  
  METHODS
  Citrate-reduced AuNPs (diameter: 12 nm) were synthesized, and characterized by transmission electron microscopy and dynamic light scattering. M2e was conjugated to AuNPs through thiol-gold interactions to form M2e-AuNP conjugates. Particle stability was confirmed by UV-visible spectra, and M2e conjugation was further characterized by x-ray photoelectron spectroscopy. Mice were immunized with M2e-AuNPs with or without CpG (cytosine-guanine rich oligonucleotide) as an adjuvant with appropriate control groups. Sera was collected and M2e-specific immunoglobulin (IgG) was measured, and immunized mice were challenged with PR8-H1N1 influenza virus.
  
  
  RESULTS
  M2e-capped AuNPs could be lyophilized and stably resuspended in water. Intranasal vaccination of mice with M2e-AuNP conjugates induced M2e-specific IgG serum antibodies, which significantly increased upon addition of soluble CpG as adjuvant. Upon challenge with lethal PR8, mice vaccinated with M2e-AuNP conjugates were only partially protected, while mice that received soluble CpG as adjuvant in addition to M2e-AuNP were fully protected.
  
  
  CONCLUSIONS
  Overall, this study demonstrates the potential of using the M2e-AuNP conjugates with CpG as an adjuvant as a platform for developing an influenza A vaccine.
authors.affiliation: Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409, USA.
authors.forename: Wenqian
authors.initials: W
authors.lastname: Tao
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Ziemer
authors.forename: Harvinder S
authors.initials: HS
authors.lastname: Gill
mesh_terms: D000818:Animals; D018899:CpG Islands; D004797:Enzyme-Linked Immunosorbent Assay; D006046:Gold / Q000737:chemistry*; D009980:Influenza A virus / Q000276:immunology*; D053768:Metal Nanoparticles / Q000737:chemistry*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006046:Gold