Lymphocyte-Tropic Simian Immunodeficiency Virus Causes Persistent Infection in the Brains of Rhesus Monkeys

AbstractMolecularly cloned SIVmac239 is the prototypical SIVmaclymphocyte-tropic virus that replicates productively in lymphocytes but poorly in macrophages. In macaques, the virus causes activation and productive infection of T lymphocytes which invade the central nervous system (CNS) early after infection in the animal. However, infected animals develop immunosuppression and AIDS but rarely overt neurological disease. In this study, we examined multiple regions of the brain and spinal cord for the presence of SIVenvsequences and histological lesions in five macaques that had been infected with SIVmac239 for 1.7 to 2.25 years. Histopathological examination of the brain revealed no lesions consistent with encephalitis; however, viral DNA was found in all five brains. In one animal the virus caused infection in a widely disseminated pattern from the frontal cortex to the distal end of the spinal cord, whereas in the other four animals infection in the CNS occurred in a nonspecific, focal pattern. Sequence analyses were performed on gp120 sequences isolated from selected regions of the CNS and compared to gp120 sequences isolated from corresponding lymph nodes, a tissue known to support productive replication of SIVmac239. Examination of the viral sequences from the CNS tissue from two animals (macaques 10F and 14F) revealed a low mutation rate when compared to the sequences isolated from the lymph node tissues. The percentage change in the amino acid sequence was approximately 1% for CNS clones versus ≥3% for clones isolated from the lymph node. The majority of the CNS viral sequences of macaques 10F and 14F had none of the genetic markers shown in a previous study to be associated with macrophage-tropic variants and indeed retained a nucleotide sequence of similar to the original lymphocyte-tropic virus used for inoculation despite almost 2 years of persistent infection in the animals. Construction of chimeric viruses with V1–V5 regions of selected macaque 10F and macaque 14F CNS-gp120 clones confirmed the predicted lymphocyte-tropic nature of theseenvgenes. In contrast, the gp120 sequences isolated from the CNS tissue of one of the other three animals (macaque 13F) had a mutation rate comparable to that observed for the lymph node clones. The CNS clones from this animal had amino acid substitutions that were previously shown to be associated with macrophage tropism. Compared to the chimeric viruses constructed with V1–V5 sequences from macaques 10F and 14F, viruses constructed with the V1–V5 sequences of several macaque 13F brain clones did not yield infectious virus. These data suggest that following entry into the CSF early during infection in the animals, SIVmac239 caused infection in the CNS. In some animals, the viralenvsequences recovered by the PCR suggested that minimal replication had occurred, whereas in another macaque virus replication had progressed with gradual selection of a more macrophage-tropic genotype

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 co-receptor virus, SIVmac239 (R71/E17), which crosses the blood brain barrier shortly after inoculation and closely mimics the natural disease course of human immunodeficiency virus (HIV) infection. The cohort was divided into 3 groups: morphine only, SIV only, and SIV + morphine. Evoked potential (EP) abnormalities in sub-clinically infected macaques were evident as early as eight weeks post-inoculation. Prolongations in EP latencies were observed in SIV-infected macaques across all modalities. Animals with the highest CSF viral loads and clinical disease showed more abnormalities than those with sub-clinical disease, confirming our previous work (Raymond et al, 1998, 1999, 2000). Although some differences were observed in auditory and visual evoked potentials in morphine treated compared to untreated SIV-infected animals, the effects were relatively small and not consistent across evoked potential type. However, morphine treated animals with subclinical disease had a clear tendency toward higher virus loads in peripheral and CNS tissues (Marcario et al., 2008) suggesting that if had been possible to follow all animals to end-stage disease, a clearer pattern of evoked potential abnormality might have emerged

Systemic Infection and Limited Replication of SHIV Vaccine Virus in Brains of Macaques Inoculated Intracerebrally with Infectious Viral DNA

AbstractSHIV deleted in two accessory genes, ΔvpuΔnef SHIVPPC, functioned well as a vaccine against later challenge with highly pathogenic SHIVKU, 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. Two measures of virus replication, detection of viral mRNA expression and circular proviral DNA, were negative for those brain regions, with the exception of the infection site in the right parietal lobe, whereas lymphoid tissues were positive by both measures. Histopathological analyses of all the sampled brain and spinal cord regions did not reveal any abnormalities. Despite intracerebral inoculation of the viral DNA, the brain was not targeted for high levels of virus replication

Integrative Genomics Identifies Gene Signature Associated with Melanoma Ulceration

Abstract Background: Despite the extensive research approaches applied to characterise malignant melanoma, no specific molecular markers are available that are clearly related to the progression of this disease. In this study, our aims were to define a gene expression signature associated with the clinical outcome of melanoma patients and to provide an integrative interpretation of the gene expression -, copy number alterations -, and promoter methylation patterns that contribute to clinically relevant molecular functional alterations

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. Using the Simian Immunodeficiency Virus/ macaque model of HIV pathogenesis, we sought to explore the impact of morphine on disease progression and pathogenesis. Sixteen Rhesus macaques were divided into 2 groups; 4 were administered saline and twelve others morphine routinely. Both groups of animals were then inoculated with SIVmacR71/17E and followed longitudinally for disease pathogenesis. The morphine group (M+V) exhibited a trend towards higher mortality rates and retardation in weight gain compared to the virus alone group. Interestingly, a subset of M+V animals succumbed to disease within weeks post-infection. These rapid progressors also exhibited a higher incidence of other end-organ pathologies. Despite the higher numbers of circulating CD4+ and CD8+T cells in the M+V group, CD4:CD8 ratios between the groups remained unchanged. Plasma and CSF viral load in the M+V group was at least a log higher than the control group. Similarly there was a trend toward increased virus build-up in the brains of M+V animals compared with controls. A novel finding of this study was the increased influx of infected monocyte/macrophages in the brains of M+V animals