title: Highly immunogenic and protective recombinant vaccine candidate expressed in transgenic plants.
abstract: Vaccine development has been hampered by difficulties in developing new and safe adjuvants, so alternative technologies that offer new avenues forward are urgently needed. The goal of this study was to express a monoclonal recombinant immune complex in a transgenic plant. A recombinant protein consisting of a tetanus toxin C fragment-specific monoclonal antibody fused with the tetanus toxin C fragment was designed and expressed. Immune complex formation occurred between individual fusion proteins to form immune complex-like aggregates that bound C1q and FcgammaRIIa receptor and could be targeted to antigen-presenting cells. Unlike antigen alone, the recombinant immune fusion complexes were highly immunogenic in mice and did not require coadministration of an adjuvant (when injected subcutaneously). Indeed, these complexes elicited antibody titers that were more than 10,000 times higher than those observed in animals immunized with the antigen alone. Furthermore, animals immunized with only 1 mug of recombinant immune complex without adjuvant were fully protected against lethal challenge. This the first report on the use of a genetic fusion between antigen and antibody to ensure an optimal expression ratio between the two moieties and to obtain fully functional recombinant immune complexes as a new vaccine model.
authors.affiliation: Department of Cellular and Molecular Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, United Kingdom. dchargel@sghms.ac.uk
authors.forename: Daniel
authors.initials: D
authors.lastname: Chargelegue
authors.forename: Pascal M W
authors.initials: PM
authors.lastname: Drake
authors.forename: Patricia
authors.initials: P
authors.lastname: Obregon
authors.forename: Alessandra
authors.initials: A
authors.lastname: Prada
authors.forename: Neil
authors.initials: N
authors.lastname: Fairweather
authors.forename: Julian K-C
authors.initials: JK
authors.lastname: Ma
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*; D015153:Blotting, Western; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D030821:Plants, Genetically Modified / Q000276:immunology*; D013744:Tetanus Toxin / Q000235:genetics / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D010446:Peptide Fragments; D013744:Tetanus Toxin; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; C040635:tetanus toxin fragment C