Immunogenicity of a lentiviral-based DNA vaccine driven by the 5'LTR of the naturally attenuated caprine arthritis encephalitis virus (CAEV) in mice and macaques.

Increasing the safety and the efficacy of existing HIV vaccines is one of the strategies that could help to promote the development of a vaccine for human use. We developed a HIV DNA vaccine (Δ4-SHIVKU2) that has been shown to induce potent polyfunctional HIV-specific T cell responses following a single dose immunization of mice and macaques. Δ4-SHIVKU2 also induced protection when immunized macaques were challenged with homologous pathogenic viruses.

Characterization of T-cell responses in macaques immunized with a single dose of HIV DNA vaccine.

The optimization of immune responses (IR) induced by HIV DNA vaccines in humans is one of the great challenges in the development of an effective vaccine against AIDS. Ideally, this vaccine should be delivered in a single dose to immunize humans. We recently demonstrated that the immunization of mice with a single dose of a DNA vaccine derived from pathogenic SHIV(KU2) (Delta4SHIV(KU2)) induced long-lasting, potent, and polyfunctional HIV-specific CD8(+) T-cell responses (G.

Rhesus macaque model of chronic opiate dependence and neuro-AIDS: longitudinal assessment of auditory brainstem responses and visual evoked potentials.

Our work characterizes the effects of opiate (morphine) dependence on auditory brainstem and visual evoked responses in a rhesus macaque model of neuro-AIDS utilizing a chronic continuous drug delivery paradigm. The goal of this study was to clarify whether morphine is protective, or if it exacerbates simian immunodeficiency virus (SIV)-related systemic and neurological disease. Our model employs a macrophage tropic CD4/CCR5 coreceptor virus, SIV(mac)239 (R71/E17), which crosses the blood-brain barrier shortly after inoculation and closely mimics the natural disease course of human immunodeficiency virus infection.

Longitudinal study to assess the safety and efficacy of a live-attenuated SHIV vaccine in long term immunized rhesus macaques.

Live-attenuated viruses derived from SIV and SHIV have provided the most consistent protection against challenge with pathogenic viruses, but concerns regarding their long-term safety and efficacy have hampered their clinical usefulness. We report a longitudinal study in which we evaluated the long-term safety and efficacy of DeltavpuSHIV(PPC), a live virus vaccine derived from SHIV(PPC). Macaques were administered two inoculations of DeltavpuSHIV(PPC), three years apart, and followed for eight years.

Nef modulates the immunogenicity of Gag encoded in a non-infectious HIV DNA vaccine.

Gag-CD8+ T cell responses are associated with immune control of HIV infection. Since during HIV infection Nef impairs T cell responses, we evaluated whether deletion of nef from a non-infectious HIV DNA vaccine (Delta4 Nef+), creating Delta5 Nef(-), would affect its immunogenicity. When compared with Delta4, mice injected with Delta5 developed significantly lower CD8+ T cell responses to Gag, but no significant change in the responses to Env was observed.

Roles of MCP-1 in development of HIV-dementia.

The encephalopathy caused by HIV, known clinically as HIV-associated dementia (HAD) and pathologically as HIV encephalitis (HIVE), results from intense infiltration of mononuclear cells, productive replication of the virus in monocyte-derived macrophages/microglia, abortive replication in astrocytes and activation of macrophages/microglia and astrocytes leading to neuronal degeneration in the brains of infected persons. Recent findings have suggested that development of HAD is based more on the activation process than on direct evidence of virus replication in the brain. Since HAD is based on the encephalitic process, major studies have been directed to the mechanisms regulating the inflammatory process.

Comparison of the effects of pathogenic simian human immunodeficiency virus strains SHIV-89.6P and SHIV-KU2 in cynomolgus macaques.

Factors explaining why human immunodeficiency virus (HIV) enhances the risk of reactivated tuberculosis (TB) are poorly understood. Unfortunately, experimental models of HIV-induced reactivated TB are lacking. We examined whether cynomolgus macaques, which accurately model latent TB in humans, could be used to model pathogenesis of HIV infection in the lungs and associated lymph nodes.

Effect of morphine on the neuropathogenesis of SIVmac infection in Indian Rhesus Macaques.

Morphine is known to prevent the development of cell-mediated immune (CMI) responses and enhance expression of the CCR5 receptor in monocyte macrophages. We undertook a study to determine the effect of morphine on the neuropathogenesis and immunopathogenesis of simian immunodeficiency virus (SIV) infection in Indian Rhesus Macaques. Hypothetically, the effect of morphine would be to prevent the development of CMI responses to SIV and to enhance the infection in macrophages.

Protection of macaques against AIDS with a live attenuated SHIV vaccine is of finite duration.

Using background data that live vaccines against several viral pathogens are effective in inducing life-long protection against disease, we undertook studies in macaques to determine the duration of protection that two live SHIV vaccines could induce against AIDS. Earlier studies had established that macaques immunized once with a live vaccine and challenged 6 months later were protected, and that other macaques given two sequential inoculations of live vaccines were protected for at least 1 year. Protection was associated with persistence of the vaccine viruses.

Activation/proliferation and apoptosis of bystander goat lymphocytes induced by a macrophage-tropic chimeric caprine arthritis encephalitis virus expressing SIV Nef.

Caprine arthritis encephalitis virus (CAEV) is the natural lentivirus of goats, well known for its tropism for macrophages and its inability to cause infection in lymphocytes. The viral genome lacks nef, tat, vpu and vpx coding sequences. To test the hypothesis that when nef is expressed by the viral genome, the virus became toxic for lymphocytes during replication in macrophages, we inserted the SIVsmm PBj14 nef coding sequences into the genome of CAEV thereby generating CAEV-nef.

Phenotypic and functional analysis of immune CD8+ T cell responses induced by a single injection of a HIV DNA vaccine in mice.

HIV DNA vaccines are potent inducers of cell-mediated immune (CMI) response in mice but elicit poor HIV-specific IFN-gamma-producing T cells in monkeys and humans. In this study, we performed kinetic analyses on splenocytes of BALB/c mice that were immunized by a single injection with a unique DNA vaccine. Using IFN-gamma-ELISPOT and multiparametric FACS analysis, we characterized the induced CMI response.

Upregulation of expression of platelet-derived growth factor and its receptor in pneumonia associated with SHIV-infected macaques.

Background: HIV-associated pulmonary disorders are the most frequent cause of AIDS-related deaths. Rhesus macaques infected with SIV-HIV (SHIV) recapitulate the human HIV-1 lung disease and provide an excellent working model to study the pathogenesis of the human syndrome. Lungs of macaques with SHIV-associated pneumonia have pathology involving macrophage and T cell infiltration that is often accompanied with concurrent opportunistic infections.

Therapy of "SHIV" infected macaques with liposomes delivering antisense interleukin-4 DNA.

Background/objectives: To explore the effects of antisense (AS) interleukin (IL)-4 on virus replication and CD8+ T-cell responses in lymph nodes and blood of macaques infected with simian human immunodeficiency virus, SHIV(89.6)P.

Methods: Six macaques were inoculated with simian human immunodeficiency virus (SHIV(89.

Immunoprophylaxis against AIDS in macaques with a lentiviral DNA vaccine.

We earlier reported that immunization of macaques with a reverse transcriptase-deleted SHIV(KU2) (DeltartSHIV(KU2)) plasmid that contained HIV-1(HXB2) env and SIV gag-nef induced protection against AIDS caused by challenge virus SHIV89.6P with a heterologous env. We further deleted vif and integrase from DeltartSHIV(KU2) and substituted the 3'LTR with SV40 poly A sequences, creating Delta4SHIV(KU2) (M) and a parallel construct containing gag-nef of HIV-1(SF2), Delta4SHIV(KU2) (H).

CXCL10-induced cell death in neurons: role of calcium dysregulation.

Chemokines play a key role in the regulation of central nervous system disease. CXCL10 over-expression has been observed in several neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease and HIV-associated dementia. More recent studies by others and us have shown that CXCL10 elicits apoptosis in fetal neurons.

Antigen expression kinetics and immune responses of mice immunized with noninfectious simian-human immunodeficiency virus DNA.

In a previous report we demonstrated that three injections of an rt-deleted noninfectious genome of the simian-human immunodeficiency virus SHIV(KU2) induced protection against AIDS in macaques (D. K. Singh, Z.

Active simian immunodeficiency virus (strain smmPGm) infection in macaque central nervous system correlates with neurologic disease.

Simian immunodeficiency virus strain smmPGm can induce neuropathology in macaques and is a model for the development of human HIV-related brain injury. For quantitative studies of proviral presence and expression in the central nervous system (CNS), we inoculated 8 macaques intravenously with the virus. Three animals were necropsied 2 to 4 weeks after development of infection, and we obtained lymphoid tissue biopsies from 5 animals before 5 weeks after infection.

A noninfectious simian/human immunodeficiency virus DNA vaccine that protects macaques against AIDS.

Simian/human immunodeficiency virus SHIV(KU2) replicates with extremely high titers in macaques. In order to determine whether the DNA of the viral genome could be used as a vaccine if the DNA were rendered noninfectious, we deleted the reverse transcriptase gene from SHIVKU2 and inserted this DNA (DeltartSHIVKU2) into a plasmid that was then used to test gene expression and immunogenicity. Transfection of Jurkat and human embryonic kidney epithelial (HEK 293) cells with the DNA resulted in production of all of the major viral proteins and their precursors and transient export of a large quantity of the Gag p27 into the supernatant fluid.

Simian human immunodeficiency virus-associated pneumonia correlates with increased expression of MCP-1, CXCL10, and viral RNA in the lungs of rhesus macaques.

Pulmonary disorders are the most frequent cause of death in HIV-1-infected individuals with AIDS and remain important even in the current era of potent antiretroviral therapy. Macaques infected with Simian/Human Immunodeficiency Virus (SHIV) develop pulmonary disease and concurrent opportunistic infections similar to those observed in HIV-infected individuals, thereby providing an excellent working model to elucidate the pathogenesis of the human lung disease. Since chemokines play a crucial role in the recruitment of inflammatory cells to tissues, we investigated the relationship between respiratory disease and the levels of chemokines, monocyte chemotactic protein-1 (MCP-1) and CXCL10, in the lungs of SHIV-infected rhesus macaques.

Inhibition of pathogenic SHIV replication in macaques treated with antisense DNA of interleukin-4.

Interleukin-4 is implicated in the pathogenesis of HIV-induced AIDS and causes enhancement of replication of virus strains that use the CXCR4 (X4) coreceptor. In this study, we explored the effects of interleukin-4 (IL-4) antisense (AS) DNA on replication of X4, simian human immunodeficiency viruses, SHIV(KU-2) and SHIV89.6P.

Investigations on four host response factors whose expression is enhanced in X4 SHIV encephalitis.

HIV encephalopathy, one of the major complications of HIV infection, involves productive virus replication in macrophages in the brain in association with heightened expression of several host response factors. One or more of these factors are thought to be the cause of the degenerative changes in neurons in the brain. Macaques infected with SIV and SHIV viruses have provided excellent working models for studying mechanisms of the human disease.

Protection against late-onset AIDS in macaques prophylactically immunized with a live simian HIV vaccine was dependent on persistence of the vaccine virus.

This is a 5-year follow-up study on 12 macaques that were immunized orally with two live SHIV vaccines, six with V1 and six with V2. All 12 macaques became persistently infected after transient replication of the vaccine viruses; all were challenged vaginally 6 mo later with homologous pathogenic SHIV(KU-1). Two of the V1 group developed full-blown AIDS without evidence of vaccine virus DNA in tissues.

Association of platelet-derived growth factor-B chain with simian human immunodeficiency virus encephalitis.

Chemokines and cytokines play a critical role in HIV infection, serving both to modulate virus replication and to recruit target cells to the site of infection. Platelet-derived growth factor (PDGF), a mitogen and chemoattractant for a wide variety of cells, is secreted by macrophages. Since macrophages are the target cells for lentiviral infection in the brain and PDGF is a known inducer of macrophage chemoattractant protein-1 (MCP)-1, a potent chemokine closely associated with HIV encephalitis, we investigated the association of PDGF-B chain (PDGF-B) with encephalitis in macaques caused by simian human immunodeficiency virus (SHIV), a chimera of HIV and SIV.

Simian immunodeficiency virus Vpr/Vpx proteins kill bystander noninfected CD4+ T-lymphocytes by induction of apoptosis.

The depletion of CD4+ T-lymphocytes central to the immunodeficiency in acquired immunodeficiency syndrome (AIDS) is largely mediated by apoptosis of both infected and uninfected cells, but the mechanisms involved and the viral proteins responsible are still poorly characterized. It has recently been suggested that, in human and simian immunodeficiency virus (HIV) and SIV, Vpr is a major modulator of apoptosis in infected cells. Recently, we have reported on a chimera of caprine arthritis-encephalitis virus (CAEV) carrying vpr/vpx genes from SIVmac239, which is replication competent in goat macrophages but not in lymphocytes or human cells.

Induction of HIV-specific antibody response and protection against vaginal SHIV transmission by intranasal immunization with inactivated SHIV-capturing nanospheres in macaques.

We have previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and that intranasal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody response in mice. In this study, to evaluate the protective effect of immunization, each three macaques was intranasally immunized with Con A-NS or inactivated simian/human immunodeficiency virus KU-2-capturing nanospheres (SHIV-NS) and then intravaginally challenged with a pathogenic virus, SHIV KU-2. After a series of six immunizations, vaginal anti-HIV-1 gp120 IgA and IgG antibodies were detected in all SHIV-NS-immunized macaques.