title: Peptide-loaded chimeric influenza virosomes for efficient in vivo induction of cytotoxic T cells.
abstract: Virus-specific CD8(+) T cells are thought to play an important role in resolving acute hepatitis C virus (HCV) infection as viral clearance has been associated with a strong and sustained CD8(+) T cell response. During the chronic state of HCV infection virus-specific T cells have a low frequency and a reduced responsiveness. Based on this, a therapeutic vaccine increasing the frequency of specific T cells is a promising alternative for the treatment of chronic HCV infection. We improved an existing vaccine platform based on immunopotentiating reconstituted influenza virosomes (IRIVs) for efficient delivery of peptide epitopes to the MHC class I antigen presentation pathway. IRIVs are proteoliposomes composed of phospholipids and influenza surface glycoproteins. Due to their fusogenic activity, IRIVs are able to deliver encapsulated macromolecules, e.g. peptides to immunocompetent cells. We developed a novel method based on chimeric virosomes [chimeric immunopotentiating reconstituted influenza virosomes (CIRIVs)] combining the high peptide-encapsulation capacity of liposomes and the fusion activity of virosomes. This new approach resulted in a 30-fold increase of the amount of incorporated soluble peptide compared with current preparation methods. To study the immunogenicity of chimeric virosomes HLA-A2.1 transgenic mice were immunized with CIRIVs containing the HCV Core132 peptide. Core132-CIRIVs efficiently induced specific cytotoxic and IFNgamma-producing T cells already with low peptide doses. Vaccine formulations, which include combinations of different HCV-derived CTL epitopes could be used to induce not only a strong but also a multi-specific CTL response, making them potential candidates for therapeutic and maybe prophylactic T cell vaccines in humans.
authors.affiliation: Pevion Biotech Ltd, Rehhagstrasse 79, CH-3018 Bern, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Amacker
authors.forename: Olivier
authors.initials: O
authors.lastname: Engler
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Kammer
authors.forename: Sonia
authors.initials: S
authors.lastname: Vadrucci
authors.forename: David
authors.initials: D
authors.lastname: Oberholzer
authors.forename: Andreas
authors.initials: A
authors.lastname: Cerny
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Zurbriggen
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015234:HLA-A Antigens / Q000235:genetics / Q000276:immunology; D015789:HLA-A2 Antigen; D019698:Hepatitis C, Chronic / Q000628:therapy; D007114:Immunization; D016233:Immunotherapy, Active; D007252:Influenza Vaccines / Q000008:administration & dosage*; D008081:Liposomes; D008561:Membrane Fusion; D051379:Mice; D008822:Mice, Transgenic; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D022721:Vaccines, Virosome; D014758:Viral Core Proteins / Q000276:immunology*; D022701:Virosomes
chemical_list: D000276:Adjuvants, Immunologic; D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D007252:Influenza Vaccines; D008081:Liposomes; D022721:Vaccines, Virosome; D014758:Viral Core Proteins; D022701:Virosomes