title: Adeno-associated virus-like particles as new carriers for B-cell vaccines: testing immunogenicity and safety in BALB/c mice.
abstract: Adeno-associated viruses (AAVs) are established vectors for gene therapy of different human diseases. AAVs are assembled of 60 capsomers, which can be genetically modified, allowing high-density display of short peptide sequences at their surface. The aim of our study was to evaluate the immunogenicity and safety of an adeno-associated virus-like particle (AAVLP)-displayed B-cell peptide epitope taking ovalbumin (OVA) as a model antigen or allergen from egg, respectively. An OVA-derived B-cell epitope was expressed as fusion protein with the AAV-2 capsid protein of VP3 (AAVLP-OVA) and for control, with the nonrelated peptide TP18 (AAVLP-TP18). Cellular internalization studies revealed an impaired uptake of AAVLP-OVA by mouse BMDC, macrophages, and human HeLa cells. Nevertheless, BALB/c mice immunized subcutaneously with AAVLP-OVA formed similarly high titers of OVA-specific IgG1 compared to mice immunized with the native OVA. The extent of the immune response was independent whether aluminum hydroxide or water in oil emulsion was used as adjuvant. Furthermore, in mice immunized with native OVA, high OVA-specific IgE levels were observed, which permitted OVA-specific mast-cell degranulation in a β-hexosaminidase release assay, whereas immunizations with AAVLP-OVA rendered background IgE levels only. Accordingly, OVA-immunized mice, but not AAVLP-OVA immunized mice, displayed an anaphylactic reaction with a significant drop of body temperature upon intravenous OVA challenge. From this mouse model, we conclude that AAVLPs that display B-cell epitope peptides on their surface are suitable vaccine candidates, especially in the field of allergy.
authors.affiliation: 1 Comparative Medicine, Messerli Research Institute, University of Veterinary Medicine Vienna , Medical University of Vienna and University of Vienna, Vienna, Austria .
authors.forename: Krisztina
authors.initials: K
authors.lastname: Manzano-Szalai
authors.forename: Kathrin
authors.initials: K
authors.lastname: Thell
authors.forename: Anna
authors.initials: A
authors.lastname: Willensdorfer
authors.forename: Margit
authors.initials: M
authors.lastname: Weghofer
authors.forename: Beatrix
authors.initials: B
authors.lastname: Pfanzagl
authors.forename: Josef
authors.initials: J
authors.lastname: Singer
authors.forename: Mirko
authors.initials: M
authors.lastname: Ritter
authors.forename: Caroline
authors.initials: C
authors.lastname: Stremnitzer
authors.forename: Ingo
authors.initials: I
authors.lastname: Flaschberger
authors.forename: Uwe
authors.initials: U
authors.lastname: Michaelis
authors.forename: Erika
authors.initials: E
authors.lastname: Jensen-Jarolim
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000906:Antibodies / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D000229:Dependovirus / Q000235:genetics*; D004337:Drug Carriers; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D005260:Female; D005822:Genetic Vectors; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000906:Antibodies; D004337:Drug Carriers; D018985:Epitopes, B-Lymphocyte; D007074:Immunoglobulin G; D014765:Viral Vaccines; D007073:Immunoglobulin E; D010047:Ovalbumin