Structure and immunogenicity of alternative forms of the simian immunodeficiency virus gag protein expressed using Venezuelan equine encephalitis virus replicon particles.
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.
Cecil
Chad
C
Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA. chad_cecil@ncsu.edu
West
Ande
A
Collier
Martha
M
Jurgens
Christy
C
Madden
Victoria
V
Whitmore
Alan
A
Johnston
Robert
R
Moore
Dominic T
DT
Swanstrom
Ronald
R
Davis
Nancy L
NL
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*
D000914:Antibodies, Viral; D015683:Gene Products, gag; D006183:H-2 Antigens; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D007371:Interferon-gamma