RESUMO
Recent studies of human immunodeficiency virus type 1 (HIV-1) infection in humans and of simian immunodeficiency virus (SIV) in rhesus monkeys have shown that resolution of the acute viral infection and control of the subsequent persistent infection are mediated by the antiviral cellular immune response. We comparatively assessed several vaccine vector delivery systems-three formulations of a plasmid DNA vector, the modified vaccinia Ankara (MVA) virus, and a replication incompetent adenovirus type 5 (Ad5) vector-expressing the SIV gag protein for their ability to elicit such immune responses in monkeys. The vaccines were tested either as a single modality or in combined modality regimens. Here we show that the most effective responses were elicited by a replication-incompetent Ad5 vector, used either alone or as a booster inoculation after priming with a DNA vector. After challenge with a pathogenic HIV-SIV hybrid virus (SHIV), the animals immunized with Ad5 vector exhibited the most pronounced attenuation of the virus infection. The replication-defective adenovirus is a promising vaccine vector for development of an HIV-1 vaccine.
Assuntos
Vacinas contra a AIDS/imunologia , Adenoviridae/imunologia , Produtos do Gene gag/imunologia , Vetores Genéticos , HIV-1/imunologia , Vacinas contra a SAIDS/imunologia , Vírus da Imunodeficiência Símia/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/genética , Adenoviridae/fisiologia , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Vírus Defeituosos/genética , Vírus Defeituosos/imunologia , Produtos do Gene gag/genética , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , HIV-1/genética , Macaca mulatta , Vacinas contra a SAIDS/administração & dosagem , Vacinas contra a SAIDS/genética , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Vírus da Imunodeficiência Símia/genética , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Replicação ViralRESUMO
A synthetic gene consisting of the reverse transcriptase (RT) and integrase (IN) domains of human immunodeficiency virus type 1 (HIV-1) pol was constructed using codons most frequently used in humans. The humanized pol gave dramatically improved levels of Rev-independent, in vitro protein production in mammalian cells and elicited much stronger cellular immunity in rodents than did virus-derived gene. Specifically, BALB/c mice were immunized with plasmids and/or recombinant vaccinia virus constructs expressing the synthetic gene. High frequencies of Pol-specific T lymphocytes were detected in these animals by the gamma interferon enzyme-linked immunospot assay against pools of short overlapping peptides. Characterization of the stimulatory peptides from these pools indicates that the optimized gene constructs are able to effectively activate both CD4+ and CD8+ T cells. Immunization of rhesus macaques with DNA vaccines expressing the humanized pol coupled to a human tissue plasminogen activator leader sequence led to pronounced in vitro cytotoxic T-lymphocyte killing activities and enhanced levels of circulating Pol-specific T cells, comparable to those observed in HIV-1-infected human subjects. Thus, optimizing the immunogenic properties of HIV-1 Pol at the level of the gene sequence validates it as an antigen and provides an important step toward the construction of a potent pol-based HIV-1 vaccine component.