Morphine potentiates neuropathogenesis of SIV infection in rhesus macaques.

Despite the advent of antiretroviral therapy, complications of HIV-1 infection with concurrent drug abuse are an emerging problem. Opiates are well known to modulate immune responses by preventing the development of cell-mediated immune responses. Their effect on the pathogenesis of HIV-1 infection however remains controversial.

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.

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.

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.

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.

Role of interleukin-4 and monocyte chemoattractant protein-1 in the neuropathogenesis of X4 simian human immunodeficiency virus infection in macaques.

Recent studies on the coreceptor usage of human immunodeficiency virus (HIV) strains associated with acquired immunodeficiency syndrome (AIDS) dementia have shown that both X4 and R5 viruses are involved in the process. The disease is associated with enhanced virus replication and monocyte chemoattractant protein (MCP)-1 production in macrophages in the brain. Using the macaque model of the disease, the authors show here that X4, macrophage-tropic simian human immunodeficiency virus (SHIV) required the enhancing effect of interleukin (IL)-4 to achieve equivalent concentrations of virus and MCP-1 that are produced in macrophages infected with R5 viruses alone.

Microarray analysis of cytokine and chemokine genes in the brains of macaques with SHIV-encephalitis.

Human immunodeficiency virus (HIV)-encephalitis results from a cascade of viral-host interactions that lead to cytokine and chemokine imbalance, which then leads to neuropathologic manifestations of the disease. These include macrophage/microglia activation, astrocytosis and neuronal dysfunction or death. As the molecular mechanisms of this process are poorly understood, we used Atlas human cytokine or cytokine receptor microarray analysis to highlight gene expression profiles that accompanied encephalitis in Simian human immunodeficiency virus (SHIV) 89.

Systemic infection and limited replication of SHIV vaccine virus in brains of macaques inoculated intracerebrally with infectious viral DNA.

SHIV deleted in two accessory genes, DeltavpuDeltanef SHIV(PPC), functioned well as a vaccine against later challenge with highly pathogenic SHIV(KU), and it was able to reach the brain after oral inoculation of live virus. In this study, the proviral genome cloned into a plasmid was inoculated as DNA intracerebrally and spread systemically. Few regions of the brain had detectable proviral DNA by real-time PCR.

Immunization of macaques with live simian human immunodeficiency virus (SHIV) vaccines conferred protection against AIDS induced by homologous and heterologous SHIVs and simian immunodeficiency virus.

To evaluate the vaccine potential of SHIVs attenuated by deletion of viral accessory genes, seven rhesus macaques were sequentially immunized with Delta vpu Delta nefSHIV-4 (vaccine-I) followed by Delta vpuSHIV(PPC) (vaccine-II). Despite the absence of virological evidence of productive infection with the vaccine strains, based on analysis of infectivity among peripheral blood mononuclear cells (PBMC) of the vaccinated animals, all seven animals developed binding as well as neutralizing antibodies against both vaccine-I and -II. The animals also developed vaccine virus-specific CTLs that recognized homologous as well as heterologous pathogenic SHIVs and SIV, and also soluble inhibitory factors that blocked the in vitro replication of the vaccine strains and different challenge viruses.

Neuropathogenesis of lentiviral infection in macaques: roles of CXCR4 and CCR5 viruses and interleukin-4 in enhancing monocyte chemoattractant protein-1 production in macrophages.

Neurological disease associated with lentiviral infection occurs mainly as a consequence of primary replication of the virus or a combination of the virus infection and replication of opportunistic pathogens in the central nervous system. Recent studies have shown that whereas the disease can be caused by CCR5 tropic viruses alone, its induction by CXCR4 (X4) tropic viruses occurred usually in association with infections caused by opportunistic pathogens and in the presence of a Th2 cytokine, interleukin (IL)-4.(1,2) Further, X4-mediated neurological disease developed preferentially in rhesus compared to pig-tailed macaques.

Presence of Intact vpu and nef genes in nonpathogenic SHIV is essential for acquisition of pathogenicity of this virus by serial passage in macaques.

Use of the macaque model of human immunodeficiency virus (HIV) pathogenesis has shown that the accessory genes nef and vpu are important in the pathogenicity of simian immunodeficiency virus (SIV) and simian-human immunodeficiency virus (SHIV). We examined the ability of two nonpathogenic SHIVs, SHIV(PPC) and DeltavpuDeltanefSHIV(PPC), to gain pathogenicity by rapid serial passage in macaques. In this study, each virus was passaged by blood intravenously four times at 4-week intervals in macaques.

Innate differences between simian-human immunodeficiency virus (SHIV)(KU-2)-infected rhesus and pig-tailed macaques in development of neurological disease.

Neurological disease associated with HIV infection results from either primary replication of the virus or a combination of virus infection and replication of opportunistic pathogens in the CNS. Recent studies indicate that the primary infection is mediated mainly by viruses that utilize CCR5 as the coreceptor; it is not known whether the syndrome can be mediated by viruses that use the CXCR4 coreceptor. The macaque model of the disease using simian immunodeficiency virus (SIV) has confirmed that CCR5-using viruses such as SIV(mac)251 can cause primary disease in the CNS.

Inhibitory and enhancing effects of IFN-gamma and IL-4 on SHIV(KU) replication in rhesus macaque macrophages: correlation between Th2 cytokines and productive infection in tissue macrophages during late-stage infection.

HIV-1 is dual-tropic for CD4+ T lymphocytes and macrophages, but virus production in the macrophages becomes manifest only during late-stage infection, after CD4+ T cell functions are lost, and when opportunistic pathogens begin to flourish. In this study, the SHIV/macaque model of HIV pathogenesis was used to assess the role of cytokines in regulating virus replication in the two cell types. We injected complete Freund's adjuvant (CFA) intradermally into SHIV(KU)-infected macaques, and infused Schistosoma mansoni eggs into the liver and lungs of others.

Selective transmission of R5-tropic HIV type 1 from dendritic cells to resting CD4+ T cells.

In an in vitro coculture model of monocyte-derived, cultured human dendritic cells (DC) with autologous CD4(+) resting T cells, CCR5 (R5)-tropic strains of HIV-1, but not CXCR4 (X4)-tropic strains, were transmitted to resting CD4+ T cells, leading to prolific viral output, although DC were susceptible to infection with either strain. Macrophages, which were also infectable with either R5- or X4-tropic strains, did not transmit infection to CD4+ cells. Highly productive HIV infection in this model appeared to be a consequence of heterokaryotic syncytium formation between infected DC and T cells since syncytia formation developed only in R5-infected DC/CD4+ cocultures.

Sequential immunization of macaques with two differentially attenuated vaccines induced long-term virus-specific immune responses and conferred protection against AIDS caused by heterologous simian human immunodeficiency Virus (SHIV(89.6)P).

Four rhesus macaques were sequentially immunized with live vaccines DeltavpuDeltanefSHIV-4 (vaccine-I) and Deltavpu SHIV(PPC) (vaccine-II). The vaccine viruses did not replicate productively in the peripheral blood mononuclear cells (PBMCs) of the vaccinated animals. All four animals developed binding antibodies against both the vaccine-I and -II envelope glycoproteins but neutralizing antibodies only against vaccine-I.

Neuropathogenesis of chimeric simian human immunodeficiency virus infection in rhesus macaques.

Comparative studies were performed to determine the neuropathogenesis of infection in macaques with simian human immunodeficiency virus (SHIV)89.6P and SHIV(KU). Both viruses utilize the CD4 receptor and CXCR4 co-receptor.

Lasting effects of transient postinoculation tenofovir [9-R-(2-Phosphonomethoxypropyl)adenine] treatment on SHIV(KU2) infection of rhesus macaques.

SHIV(KU2) replicates to high levels in inoculated macaques and reproducibly causes an acute depletion of CD4(+) T cells. We evaluated the ability of treatment with the antiretroviral drug 9-R-(2-phosphonomethoxypropyl)adenine (PMPA; tenofovir), begun 7 days postinoculation, to inhibit viral replication and associated pathogenesis. Highly productive infection (plasma viral RNA > 10(6) copy eq/mL) was present and CD4 depletion had started when treatment was initiated.

Morphological correlates of neurological dysfunction in macaques infected with neurovirulent simian immunodeficiency virus.

The pattern of neurological disease caused by human immunodeficiency virus (HIV) infection of the central nervous system (CNS) was investigated using a macaque model of acquired immune defiency syndrome (AIDS). Seven of nine macaques inoculated with neurovirulent simian imunodeficiency virus (SIVmac ) developed AIDS within 3 months. Four of these had clinically obvious neurological disease and extensive conduction defects in the form of latency increases in evoked potential (EP) responses.

Oral immunization of macaques with attenuated vaccine virus induces protection against vaginally transmitted AIDS.

The chimeric simian-human immunodeficiency virus SHIVKU-1, bearing the envelope of human immunodeficiency virus type 1 (HIV-1), causes fulminant infection with subtotal loss of CD4(+) T cells followed by development of AIDS in intravaginally inoculated macaques and thus provides a highly relevant model of sexually transmitted disease caused by HIV-1 in human beings. Previous studies using this SHIV model had shown that the vpu and nef genes were important in pathogenesis of the infection, and so we deleted portions of these genes to create two vaccines, DeltavpuDeltanefSHIV-4 (vaccine 1) and DeltavpuSHIVPPc (vaccine 2). Six adult macaques were immunized subcutaneously with vaccine 1, and six were immunized orally with vaccine 2.

Chimeric SHIV that causes CD4+ T cell loss and AIDS in rhesus macaques.

By animal to animal passage in rhesus and pig-tailed macaques, we developed a rhesus model of HIV-1 disease in humans. Rhesus macaques infected with a cell-free stock of SHIVKU-2 developed CD4+ T cell loss, primary lentiviral encephalitis and pneumonia, and AIDS. Six of nine rhesus macaques died within eight months post-inoculation, while the remaining three are at five, five, and eight months post-inoculation, respectively.

Simian-human immunodeficiency virus (SHIV) containing the nef/long terminal repeat region of the highly virulent SIVsmmPBj14 causes PBj-like activation of cultured resting peripheral blood mononuclear cells, but the chimera showed No increase in virulence.

SIVsmmPBj14 is a highly pathogenic lentivirus which causes acute diarrhea, rash, massive lymphocyte proliferation predominantly in the gastrointestinal tract, and death within 7 to 14 days. In cell culture, the virus has mitogenic effects on resting macaque T lymphocytes. In contrast, SIVmac239 causes AIDS in rhesus macaques, generally within 2 years after inoculation.

Infected macaques that controlled replication of SIVmac or nonpathogenic SHIV developed sterilizing resistance against pathogenic SHIV(KU-1).

Twenty macaques were used to evaluate the ability of nonpathogenic SIV(mac) or nonpathogenic chimeric SIV-HIV (SHIV) to induce protection in macaques against superinfection with a pathogenic variant of SHIV (SHIV(KU-1)) originally containing the tat, rev, vpu, and env of HIV-1 (strain HXB2) in a genetic background of SIV(mac)239. Specifically, three macaques inoculated with molecularly cloned, macrophage-tropic SIV(mac)LG1 developed an early systemic infection but recovered with only traces of SIV(mac) DNA in visceral lymphoid tissues. These animals were then inoculated parenterally with pathogenic SHIV(KU-1).