title: Assembly of trans-encapsidated recombinant viral vectors engineered from Tobacco mosaic virus and Semliki Forest virus and their evaluation as immunogens.
abstract: RNA virus vectors are attractive vaccine delivery agents capable of directing high-level gene expression without integration into host cell DNA. However, delivery of non-encapsidated RNA viral vectors into animal cells is relatively inefficient. By introducing the tobacco mosaic virus (TMV) origin of assembly into the RNA genome of Semliki Forest virus (SFV), we generated an SFV expression vector that could be efficiently packaged (trans-encapsidated) in vitro by purified TMV coat protein (CP). Using cellular assays, pseudovirus disassembly, RNA replication and reporter gene expression were demonstrated. We also evaluated the immune response to trans-encapsidated recombinant SFV carrying a model antigen gene (beta-galactosidase) in C57/B6 mice. Relative to RNA alone, vector encapsidation significantly improved the humoral and cellular immune responses. Furthermore, reassembly with recombinant TMV CPs permitted the display of peptide epitopes on the capsid surface as either genetic fusions or through chemical conjugation, to complement the immunoreactivity of the encapsidated RNA genetic payload. The SFV vector/TMV CP system described provides an alternative nucleic acid delivery mechanism that is safe, easy to manufacture in vitro and that also facilitates the generation of unique nucleic acid/protein antigen compositions.
authors.affiliation: Large Scale Biology Corporation, 3333 Vaca Valley Parkway, Suite 1000, Vacaville, CA 95688, USA.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Smith
authors.forename: Tina
authors.initials: T
authors.lastname: Corbo
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Bernales
authors.forename: John A
authors.initials: JA
authors.lastname: Lindbo
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Pogue
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Palmer
authors.forename: Alison A
authors.initials: AA
authors.lastname: McCormick
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D036022:Capsid Proteins / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors / Q000378:metabolism*; D007114:Immunization; D007115:Immunization Schedule; D007279:Injections, Subcutaneous; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D012367:RNA, Viral / Q000378:metabolism*; D012672:Semliki forest virus / Q000235:genetics* / Q000378:metabolism*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014027:Tobacco Mosaic Virus / Q000235:genetics / Q000502:physiology*; D014764:Viral Proteins / Q000276:immunology / Q000378:metabolism*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014779:Virus Replication; D001616:beta-Galactosidase / Q000276:immunology / Q000378:metabolism*
chemical_list: D000914:Antibodies, Viral; D036022:Capsid Proteins; C009496:H protein, Tobacco mosaic virus; D012367:RNA, Viral; D014764:Viral Proteins; D014765:Viral Vaccines; D001616:beta-Galactosidase