title: The L1 protein of human papilloma virus 16 expressed by a fowlpox virus recombinant can assemble into virus-like particles in mammalian cell lines but elicits a non-neutralising humoral response.
abstract: Human papilloma virus (HPV)-16 is the prevalent genotype associated with cervical tumours. Virus-like-particle (VLP)-based vaccines have proven to be effective in limiting new infections of high-risk HPVs, but their high cost has hampered their use, especially in the poor developing countries. Avipox-based recombinants are replication-restricted to avian species and represent efficient and safe vectors also for immunocompromised hosts, as they can elicit a complete immune response. A new fowlpox virus recombinant encoding HPV-L1 (FPL1) was engineered and evaluated side-by-side with a FP recombinant co-expressing L1 and green fluorescent protein (FPL1GFP) for correct expression of L1 in vitro in different cell lines, as confirmed by Western blotting, immunofluorescence, real-time PCR, and electron microscopy. Mice were also immunised to determine its immunogenicity. Here, we demonstrate that the FPL1 recombinant better expresses L1 in the absence of GFP, correctly assembles structured capsomers into VLPs, and elicits an immune response in a preclinical animal model. To our knowledge, this is the first report of HPV VLPs assembled in eukaryotic cells using an avipox recombinant.
authors: Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy. Electronic address: massimiliano.bissa@studenti.unimi.it.
authors: Massimiliano
authors: M
authors: Bissa
authors: Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy. Electronic address: carlo.zanotto@unimi.it.
authors: Carlo
authors: C
authors: Zanotto
authors: Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy. Electronic address: sole.pacchioni@studenti.unimi.it.
authors: Sole
authors: S
authors: Pacchioni
authors: Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy. Electronic address: lucaseverino@libero.it.
authors: Luca
authors: L
authors: Volonté
authors: HPV-UNIT, Laboratory of Virology, Regina Elena Cancer Institute, Rome, Italy. Electronic address: venuti@ifo.it.
authors: Aldo
authors: A
authors: Venuti
authors: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy. Electronic address: david.lembo@unito.it.
authors: David
authors: D
authors: Lembo
authors: Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy; Cellular and Molecular Pharmacology Section, CNR Institute of Neurosciences, University of Milan, Milan, Italy. Electronic address: carlo.degiulimorghen@unimi.it.
authors: Carlo
authors: C
authors: De Giuli Morghen
authors: Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy; Cellular and Molecular Pharmacology Section, CNR Institute of Neurosciences, University of Milan, Milan, Italy. Electronic address: Antonia.Radaelli@unimi.it.
authors: Antonia
authors: A
authors: Radaelli
mesh_terms: D000818:Animals; D015153:Blotting, Western; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D005587:Fowlpox virus / Q000235:genetics*; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics; D052162:Human papillomavirus 16 / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D051379:Mice; D008854:Microscopy, Electron; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D053918:Papillomavirus Vaccines / Q000235:genetics / Q000276:immunology*; D060888:Real-Time Polymerase Chain Reaction; D019076:Transgenes; D058425:Vaccines, Virus-Like Particle / Q000276:immunology*
chemical_list: D036022:Capsid Proteins; D009856:Oncogene Proteins, Viral; D053918:Papillomavirus Vaccines; D058425:Vaccines, Virus-Like Particle; D049452:Green Fluorescent Proteins; C063317:L1 protein, Human papillomavirus type 16
keywords: Fowlpox virus; HPV; L1 protein; Recombinant vaccines; VLPs