title: Nanocarriers for DNA Vaccines: Co-Delivery of TLR-9 and NLR-2 Ligands Leads to Synergistic Enhancement of Proinflammatory Cytokine Release.
abstract: Adjuvants enhance immunogenicity of vaccines through either targeted antigen delivery or stimulation of immune receptors. Three cationic nanoparticle formulations were evaluated for their potential as carriers for a DNA vaccine, and muramyl dipeptide (MDP) as immunostimulatory agent, to induce and increase immunogenicity ofMycobacterium tuberculosisantigen encoding plasmid DNA (pDNA). The formulations included (1) trimethyl chitosan (TMC) nanoparticles, (2) a squalene-in-water nanoemulsion, and (3) a mineral oil-in-water nanoemulsion. The adjuvant effect of the pDNA-nanocomplexes was evaluated by serum antibody analysis in immunized mice. All three carriers display a strong adjuvant effect, however, only TMC nanoparticles were capable to bias immune responses towards Th1. pDNA naturally contains immunostimulatory unmethylated CpG motifs that are recognized by Toll-like receptor 9 (TLR-9). In mechanisticin vitrostudies, activation of TLR-9 and the ability to enhance immunogenicity by simultaneously targeting TLR-9 and NOD-like receptor 2 (NLR-2) was determined by proinflammatory cytokine release in RAW264.7 macrophages. pDNA in combination with MDP was shown to significantly increase proinflammatory cytokine release in a synergistic manner, dependent on NLR-2 activation. In summary, novel pDNA-Ag85A loaded nanoparticle formulations, which induce antigen specific immune responses in mice were developed, taking advantage of the synergistic combinations of TLR and NLR agonists to increase the adjuvanticity of the carriers used.
authors.affiliation: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland. johanna.poecheim@unige.ch.
authors.forename: Johanna
authors.initials: J
authors.lastname: Poecheim
authors.affiliation: Vaccine Formulation Laboratory, Department of Biochemistry, University of Lausanne, Chemin des Boveresses 155, 1066 Epalinges, Switzerland. simon.heuking@gmx.net.
authors.forename: Simon
authors.initials: S
authors.lastname: Heuking
authors.affiliation: Vaccine Formulation Laboratory, Department of Biochemistry, University of Lausanne, Chemin des Boveresses 155, 1066 Epalinges, Switzerland. livia.brunner@unil.ch.
authors.forename: Livia
authors.initials: L
authors.lastname: Brunner
authors.affiliation: Vaccine Formulation Laboratory, Department of Biochemistry, University of Lausanne, Chemin des Boveresses 155, 1066 Epalinges, Switzerland. christophe.barnier-quer@unil.ch.
authors.forename: Christophe
authors.initials: C
authors.lastname: Barnier-Quer
authors.affiliation: Vaccine Formulation Laboratory, Department of Biochemistry, University of Lausanne, Chemin des Boveresses 155, 1066 Epalinges, Switzerland. nicolas.collin@unil.ch.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Collin
authors.affiliation: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland. gerrit.borchard@unige.ch.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Borchard
keywords: DNA vaccine; NOD-like receptor; adjuvants; cationic nanoparticles; muramyl dipeptide; toll-like receptor