title: Duality of β-glucan microparticles: antigen carrier and immunostimulants.
abstract: Designing efficient recombinant mucosal vaccines against enteric diseases is still a major challenge. Mucosal delivery of recombinant vaccines requires encapsulation in potent immunostimulatory particles to induce an efficient immune response. This paper evaluates the capacity of β-glucan microparticles (GPs) as antigen vehicles and characterizes their immune-stimulatory effects. The relevant infectious antigen FedF was chosen to be loaded inside the microparticles. The incorporation of FedF inside the particles was highly efficient (roughly 85%) and occurred without antigen degradation. In addition, these GPs have immunostimulatory effects as well, demonstrated by the strong reactive oxygen species (ROS) production by porcine neutrophils upon their recognition. Although antigen-loaded GPs still induce ROS production, antigen loading decreases this production by neutrophils for reasons yet unknown. However, these antigen-loaded GPs are still able to bind their specific β-glucan receptor, demonstrated by blocking complement receptor 3, which is the major β-glucan receptor on porcine neutrophils. The dual character of these particles is confirmed by a T-cell proliferation assay. FedF-loaded particles induce a significantly higher FedF-specific T-cell proliferation than soluble FedF. Taken together, these results show that GPs are efficient antigen carriers with immune-stimulatory properties.
authors.affiliation: Department of Virology, Parasitology and Immunology, Ghent University, Merelbeke, Ghent, Belgium.
authors.forename: Kim
authors.initials: K
authors.lastname: Baert
authors.affiliation: Department of Pharmaceutics, Ghent University, Merelbeke, Ghent, Belgium.
authors.forename: Bruno G
authors.initials: BG
authors.lastname: De Geest
authors.affiliation: Structural Biology Research Centre, VIB, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Henri
authors.initials: H
authors.lastname: De Greve
authors.affiliation: Department of Virology, Parasitology and Immunology, Ghent University, Merelbeke, Ghent, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Cox
authors.affiliation: Department of Virology, Parasitology and Immunology, Ghent University, Merelbeke, Ghent, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Devriendt
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology; D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000941:Antigens / Q000276:immunology*; D049109:Cell Proliferation / Q000187:drug effects; D029968:Escherichia coli Proteins / Q000276:immunology; D056747:Immunomodulation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D021122:Protein Subunits / Q000378:metabolism; D011951:Receptors, Complement / Q000378:metabolism; D034421:Sus scrofa; D013601:T-Lymphocytes / Q000187:drug effects; D047071:beta-Glucans / Q000276:immunology* / Q000494:pharmacology*
chemical_list: D018829:Adhesins, Bacterial; D000276:Adjuvants, Immunologic; D000941:Antigens; D029968:Escherichia coli Proteins; C440653:FedF protein, E coli; D021122:Protein Subunits; D011951:Receptors, Complement; D047071:beta-Glucans
keywords: FedF; antigen delivery vehicle; immunostimulants; β-glucan microparticles