title: HIV-1 virus-like particles produced by stably transfected Drosophila S2 cells: a desirable vaccine component.
abstract: The development of a successful vaccine against human immunodeficiency virus type 1 (HIV-1) likely requires immunogens that elicit both broadly neutralizing antibodies against envelope spikes and T cell responses that recognize multiple viral proteins. HIV-1 virus-like particles (VLP), because they display authentic envelope spikes on the particle surface, may be developed into such immunogens. However, in one way or the other current systems for HIV-1 VLP production have many limitations. To overcome these, in the present study we developed a novel strategy to produce HIV-1 VLP using stably transfected Drosophila S2 cells. We cotransfected S2 cells with plasmids encoding HIV-1 envelope, Gag, and Rev proteins and a selection marker. After stably transfected S2 clones were established, HIV-1 VLP and their immunogenicity in mice were carefully evaluated. Here, we report that HIV-1 envelope proteins are properly cleaved, glycosylated, and incorporated into VLP with Gag. The amount of VLP released into culture supernatants is comparable to those produced by insect cells infected with recombinant baculoviruses. Moreover, cryo-electron microscopy tomography revealed average 17 spikes per purified VLP, and antigenic epitopes on the spikes were recognized by the broadly neutralizing antibodies 2G12, b12, VRC01, and 4E10 but not by PG16. Finally, mice primed with DNA and boosted with VLP in the presence of CpG exhibited anti-envelope antibody responses, including ELISA-binding, neutralizing, antibody-dependent cell-mediated cytotoxicity and antibody-dependent cell-mediated viral inhibition, as well as envelope and Gag-specific CD8 T cell responses. Thus, we conclude that HIV-1 VLP produced by the S2 expression system has many desirable features to be developed into a vaccine component against HIV-1.
authors.affiliation: Unit of Antiviral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Lifei
authors.initials: L
authors.lastname: Yang
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Song
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Li
authors.forename: Xiaoxing
authors.initials: X
authors.lastname: Huang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liu
authors.forename: Heng
authors.initials: H
authors.lastname: Ding
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.forename: Paul
authors.initials: P
authors.lastname: Zhou
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology*; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D004331:Drosophila melanogaster; D057809:HEK293 Cells; D015483:HIV Antibodies / Q000097:blood / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D051379:Mice; D054735:Phosphorothioate Oligonucleotides / Q000276:immunology; D014162:Transfection; D058425:Vaccines, Virus-Like Particle / Q000276:immunology*; D054299:env Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000276:immunology*; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000276:immunology*
chemical_list: D016915:AIDS Vaccines; D057134:Antibodies, Neutralizing; D015483:HIV Antibodies; D054735:Phosphorothioate Oligonucleotides; D058425:Vaccines, Virus-Like Particle; D054299:env Gene Products, Human Immunodeficiency Virus; D054301:gag Gene Products, Human Immunodeficiency Virus