title: Structure and immunogenicity of alternative forms of the simian immunodeficiency virus gag protein expressed using Venezuelan equine encephalitis virus replicon particles.
abstract: Venezuelan equine encephalitis virus replicon particles (VRP) were engineered to express different forms of SIV Gag to compare expression in vitro, formation of intra- and extracellular structures and induction of humoral and cellular immunity in mice. The three forms examined were full-length myristylated SIV Gag (Gagmyr+), full-length Gag lacking the myristylation signal (Gagmyr-) or a truncated form of Gagmyr- comprising only the matrix and capsid domains (MA/CA). Comparison of VRP-infected primary mouse embryo fibroblasts, mouse L929 cells and primate Vero cells showed comparable expression levels for each protein, as well as extracellular virus-like particles (VRP-Gagmyr+) and distinctive cytoplasmic aggregates (VRP-Gagmyr-) with each cell type. VRP were used to immunize BALB/c mice, and immune responses were compared using an interferon (IFN)-gamma ELISPOT assay and a serum antibody ELISA. Although all three VRP generated similar levels of IFN-gamma-producing cells at 1 week post-boost, at 10 weeks post-boost the MA/CA-VRP-induced response was maintained at a significantly higher level relative to that induced by Gagmyr+-VRP. Antibody responses to MA/CA-VRP and Gagmyr+-VRP were not significantly different.
authors.affiliation: Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA. chad_cecil@ncsu.edu
authors.forename: Chad
authors.initials: C
authors.lastname: Cecil
authors.forename: Ande
authors.initials: A
authors.lastname: West
authors.forename: Martha
authors.initials: M
authors.lastname: Collier
authors.forename: Christy
authors.initials: C
authors.lastname: Jurgens
authors.forename: Victoria
authors.initials: V
authors.lastname: Madden
authors.forename: Alan
authors.initials: A
authors.lastname: Whitmore
authors.forename: Robert
authors.initials: R
authors.lastname: Johnston
authors.forename: Dominic T
authors.initials: DT
authors.lastname: Moore
authors.forename: Ronald
authors.initials: R
authors.lastname: Swanstrom
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Davis
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004622:Embryo, Mammalian / Q000166:cytology; D004666:Encephalitis Virus, Venezuelan Equine / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005347:Fibroblasts; D015683:Gene Products, gag / Q000737:chemistry / Q000276:immunology*; D005822:Genetic Vectors / Q000235:genetics*; D006183:H-2 Antigens / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D046529:Microscopy, Electron, Transmission; D023421:Models, Animal; D011247:Pregnancy; D012093:Replicon / Q000235:genetics; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014709:Vero Cells; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D015683:Gene Products, gag; D006183:H-2 Antigens; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D007371:Interferon-gamma