RESUMO
We investigated immunogenic properties of native envelope glycoproteins derived from HIV-1 (subtype B). Our main objective was to assess whether the design of multivalent vaccines affects generation of neutralizing antibodies against primary viruses. Recombinant Semliki Forest virus (SFV) particles producing various HIV-1 envelope glycoproteins were used as vaccine vectors. The following multivalent vaccination approaches were compared: 1) immunization with a mixture of recombinant SFV expressing envelope glycoproteins derived from three HIV-1 primary isolates and two T-cell laboratory-adapted (TCLA) viruses; 2) immunization with a mixture of recombinant SFV expressing only the envelope glycoproteins derived from three HIV-1 primary isolates; 3) sequential immunizations with the recombinant SFV expressing the envelope glycoproteins derived from three HIV-1 primary isolates and two TCLA viruses, respectively. Two monovalent vaccine approaches using SFV expressing envelope glycoproteins derived from a single primary isolate or TCLA virus were also included in the study. The multivalent vaccination strategies based on SFV vaccine vectors did not induce more neutralizing antibodies than the previously tested TCLA envelope immunogens, which gave disappointing results against primary isolates.
Assuntos
Vacinas contra a AIDS/imunologia , Infecções por HIV/virologia , HIV-1/imunologia , Linfócitos T/virologia , Proteínas do Envelope Viral/imunologia , Animais , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Vetores Genéticos , Anticorpos Anti-HIV/sangue , HIV-1/isolamento & purificação , HIV-1/metabolismo , Humanos , Esquemas de Imunização , Testes de Neutralização , Coelhos , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Vírus da Floresta de Semliki/genética , Vírus da Floresta de Semliki/metabolismo , Proteínas do Envelope Viral/genéticaRESUMO
We have recently shown that the level of cell surface expression of envelope glycoproteins derived from various human immunodeficiency virus type 1 (HIV-1) primary isolates (PI) was lower than those of envelope glycoproteins derived from T-cell laboratory-adapted (TCLA) HIV-1 (D. Brand et al., 2000, Virology 271, 350-362). We investigated this phenomenon by comparing the cell surface expression of chimeric envelope glycoproteins constructed by swapping the gp120 surface and gp41 transmembrane glycoproteins of the TCLA HIV-1MN and the PI HIV-1(133), HIV-1G365, or HIV-1EFRA. We found that each chimeric envelope construct had a cell surface-specific pattern of expression similar to that of the parental envelope glycoproteins corresponding to the gp41. Thus, the difference in cell surface expression observed between TCLA viruses and various PI is probably due to a signal located in gp41. Identification of this signal may be important for the design of PI envelope-derived immunogens and may increase our understanding of the mechanisms by which HIV-1 escapes from the immune system.
Assuntos
Regulação Viral da Expressão Gênica , Proteína gp120 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/genética , Glicoproteínas de Membrana/genética , Membrana Celular/metabolismo , Genes Virais , HIV-1/isolamento & purificação , Humanos , Proteínas Recombinantes de Fusão/genéticaRESUMO
We investigated the protein/protein interactions that occur during human immunodeficiency virus (HIV-1) budding. We evaluated the binding to Pr55Gag particles of peptides mapping to the cytoplasmic tail of gp41TM and of host-cell proteins, in a cell-free, in vitro assay. Host-cell proteins and irrelevant viral envelope peptides did not bind. Peptides corresponding to a large central domain of the gp41TM cytoplasmic tail (93 residues) bound to Pr55Gag particles. This demonstrates that a Gag/Env interaction is responsible for the specific incorporation of the Env glycoprotein into nascent HIV-1 virions, and defines more accurately the gp41TM domain involved in this interaction.
Assuntos
Produtos do Gene gag/química , Produtos do Gene gag/metabolismo , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/metabolismo , HIV-1/fisiologia , Precursores de Proteínas/química , Precursores de Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Linhagem Celular , Membrana Celular/ultraestrutura , Membrana Celular/virologia , Cricetinae , HIV-1/crescimento & desenvolvimento , HIV-1/ultraestrutura , Humanos , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Mapeamento de Peptídeos , TransfecçãoRESUMO
The native envelope glycoproteins of primary HIV-1 virions have weaker antigenicity than do T-cell laboratory-adapted (TCLA) viruses. These antigenic properties require further evaluation if recombinant envelope glycoproteins are produced as part of a vaccine strategy. In this study, we compared the antigenicity of recombinant envelope glycoproteins derived from three primary isolates (PI) (HIV-1(BX08), HIV-1(CHA), and HIV-1(133)) and two TCLA viruses (HIV-1(HXB2) and HIV-1(MN)) produced using the Semliki Forest virus (SFV) system. This analysis was performed by radioimmunoprecipitation assays and flow cytometry. The results suggest that the SFV produces envelope glycoproteins with features in common with the envelopes found in naturally occurring virions. In particular, the PI envelopes had weak heterogeneous antigenic properties. However, the cytometric analysis also showed that there was less envelope glycoprotein on the cell surface for the PI envelopes than for those of TCLA viruses, suggesting differences in their intracellular trafficking. The immunogenic properties of the various envelope glycoproteins were evaluated in mice using recombinant SFV particles as vaccine vectors. The PI envelopes were less immunogenic than the TCLA envelopes, probably due to both their low antigenicity and cell surface expression level. Thus, it may be difficult to design an effective vaccine based on native recombinant PI envelopes.
Assuntos
Glicoproteínas/imunologia , Antígenos HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp160 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Proteínas Recombinantes de Fusão/imunologia , Adaptação Fisiológica , Animais , Linhagem Celular , Cricetinae , Citometria de Fluxo/métodos , Glicoproteínas/genética , Antígenos HIV/genética , Proteína gp120 do Envelope de HIV/genética , Proteína gp160 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/genética , HIV-1/isolamento & purificação , HIV-1/fisiologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Testes de Precipitina , Proteínas Recombinantes de Fusão/genética , Linfócitos T/virologiaRESUMO
The Semliki Forest virus (SFV) system seems to be a useful new approach for generating effective immune responses against HIV-1 in animal models. We evaluated this system by comparing the humoral immune responses raised in mice immunized against the HIV-1 envelope with the SFV system, a DNA vaccine, and a recombinant Env glycoprotein. gp160 ELISA antibody titers (204,800) were highest in the sera from mice immunized with recombinant Semliki Forest virus particles. These sera contained antibodies to the CD4-binding site and recognized linear epitopes on gp120 and gp41 that were also recognized by a pool of sera from HIV1-infected individuals. This demonstrates that the HIV-1 envelope produced in vivo by the SFV system does not fold aberrantly. A low level of neutralizing antibodies against the HIV-1LAI strain was also detected in the serum of one mouse immunized with recombinant SFV particles, suggesting that booster injections should be given to achieve a more effective immune response. SFV recombinant particles induced the strongest humoral responses to the HIV-1 envelope of all the potential HIV env vaccines tested.
