Publications by authors named "Patrick Autissier"

39 Publications

Phyloanatomic characterization of the distinct T cell and monocyte contributions to the peripheral blood HIV population within the host.

Virus Evol 2020 Jan 27;6(1):veaa005. Epub 2020 Apr 27.

Department of Pathology, Immunology, and Laboratory Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL 32601, USA.

Human immunodeficiency virus (HIV) is a rapidly evolving virus, allowing its genetic sequence to act as a fingerprint for epidemiological processes among, as well as within, individual infected hosts. Though primarily infecting the CD4+ T-cell population, HIV can also be found in monocytes, an immune cell population that differs in several aspects from the canonical T-cell viral target. Using single genome viral sequencing and statistical phylogenetic inference, we investigated the viral RNA diversity and relative contribution of each of these immune cell types to the viral population within the peripheral blood. Results provide evidence of an increased prevalence of circulating monocytes harboring virus in individuals with high viral load in the absence of suppressive antiretroviral therapy. Bayesian phyloanatomic analysis of three of these individuals demonstrated a measurable role for these cells, but not the circulating T-cell population, as a source of cell-free virus in the plasma, supporting the hypothesis that these cells can act as an additional conduit of virus spread.
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http://dx.doi.org/10.1093/ve/veaa005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7185683PMC
January 2020

Characterizing smoking-induced transcriptional heterogeneity in the human bronchial epithelium at single-cell resolution.

Sci Adv 2019 12 11;5(12):eaaw3413. Epub 2019 Dec 11.

Department of Medicine, Boston University School of Medicine, Boston, MA, USA.

The human bronchial epithelium is composed of multiple distinct cell types that cooperate to defend against environmental insults. While studies have shown that smoking alters bronchial epithelial function and morphology, its precise effects on specific cell types and overall tissue composition are unclear. We used single-cell RNA sequencing to profile bronchial epithelial cells from six never and six current smokers. Unsupervised analyses led to the characterization of a set of toxin metabolism genes that localized to smoker ciliated cells, tissue remodeling associated with a loss of club cells and extensive goblet cell hyperplasia, and a previously unidentified peri-goblet epithelial subpopulation in smokers who expressed a marker of bronchial premalignant lesions. Our data demonstrate that smoke exposure drives a complex landscape of cellular alterations that may prime the human bronchial epithelium for disease.
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http://dx.doi.org/10.1126/sciadv.aaw3413DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6905872PMC
December 2019

Temporal/compartmental changes in viral RNA and neuronal injury in a primate model of NeuroAIDS.

PLoS One 2018 11;13(5):e0196949. Epub 2018 May 11.

Department of Radiology, Neuroradiology Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America.

Despite the advent of highly active anti-retroviral therapy HIV-associated neurocognitive disorders (HAND) continue to be a significant problem. Furthermore, the precise pathogenesis of this neurodegeneration is still unclear. The objective of this study was to examine the relationship between infection by the simian immunodeficiency virus (SIV) and neuronal injury in the rhesus macaque using in vivo and postmortem sampling techniques. The effect of SIV infection in 23 adult rhesus macaques was investigated using an accelerated NeuroAIDS model. Disease progression was modulated either with combination anti-retroviral therapy (cART, 4 animals) or minocycline (7 animals). Twelve animals remained untreated. Viral loads were monitored in the blood and cerebral spinal fluid, as were levels of activated monocytes in the blood. Neuronal injury was monitored in vivo using magnetic resonance spectroscopy. Viral RNA was quantified in brain tissue of each animal postmortem using reverse transcription polymerase chain reaction (RT-PCR), and neuronal injury was assessed by immunohistochemistry. Without treatment, viral RNA in plasma, cerebral spinal fluid, and brain tissue appears to reach a plateau. Neuronal injury was highly correlated both to plasma viral levels and a subset of infected/activated monocytes (CD14+CD16+), which are known to traffic the virus into the brain. Treatment with either cART or minocycline decreased brain viral levels and partially reversed alterations in in vivo and immunohistochemical markers for neuronal injury. These findings suggest there is significant turnover of replicating virus within the brain and the severity of neuronal injury is directly related to the brain viral load.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0196949PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5947913PMC
July 2018

Monocyte subsets exhibit transcriptional plasticity and a shared response to interferon in SIV-infected rhesus macaques.

J Leukoc Biol 2018 01 14;103(1):141-155. Epub 2017 Dec 14.

Department of Biology, Boston College, Chestnut Hill, Massachusetts, USA.

The progression to AIDS is influenced by changes in the biology of heterogeneous monocyte subsets. Classical (CD14++CD16-), intermediate (CD14++CD16+), and nonclassical (CD14+CD16++) monocytes may represent progressive stages of monocyte maturation or disparate myeloid lineages with different turnover rates and function. To investigate the relationship between monocyte subsets and the response to SIV infection, we performed microarray analysis of monocyte subsets in rhesus macaques at three time points: prior to SIV infection, 26 days postinfection, and necropsy with AIDS. Genes with a 2-fold change between monocyte subsets (2023 genes) or infection time points (424 genes) were selected. We identify 172 genes differentially expressed among monocyte subsets in both uninfected and SIV-infected animals. Classical monocytes express genes associated with inflammatory responses and cell proliferation. Nonclassical monocytes express genes associated with activation, immune effector functions, and cell cycle inhibition. The classical and intermediate subsets are most similar at all time points, and transcriptional similarity between intermediate and nonclassical monocytes increases with AIDS. Cytosolic sensors of nucleic acids, restriction factors, and IFN-stimulated genes are induced in all three subsets with AIDS. We conclude that SIV infection alters the transcriptional relationship between monocyte subsets and that the innate immune response to SIV infection is conserved across monocyte subsets.
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http://dx.doi.org/10.1002/JLB.4A0217-047RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6869333PMC
January 2018

Insights into the Impact of CD8 Immune Modulation on Human Immunodeficiency Virus Evolutionary Dynamics in Distinct Anatomical Compartments by Using Simian Immunodeficiency Virus-Infected Macaque Models of AIDS Progression.

J Virol 2017 12 14;91(23). Epub 2017 Nov 14.

Emerging Pathogens Institute and Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, Florida, USA

A thorough understanding of the role of human immunodeficiency virus (HIV) intrahost evolution in AIDS pathogenesis has been limited by the need for longitudinally sampled viral sequences from the vast target space within the host, which are often difficult to obtain from human subjects. CD8 lymphocyte-depleted macaques infected with simian immunodeficiency virus (SIV) provide an increasingly utilized model of pathogenesis due to clinical manifestations similar to those for HIV-1 infection and AIDS progression, as well as a characteristic rapid disease onset. Comparison of this model with SIV-infected non-CD8 lymphocyte-depleted macaques also provides a unique opportunity to investigate the role of CD8 cells in viral evolution and population dynamics throughout the duration of infection. Using several different phylogenetic methods, we analyzed viral sequences obtained from extensive longitudinal sampling of multiple tissues and enriched leukocyte populations from SIVmac251-infected macaques with or without CD8 lymphocyte depletion. SIV evolutionary and selection patterns in non-CD8 lymphocyte-depleted animals were characterized by sequential population turnover and continual viral adaptation, a scenario readily comparable to intrahost evolutionary patterns during human HIV infection in the absence of antiretroviral therapy. Alternatively, animals that were depleted of CD8 lymphocytes exhibited greater variation in population dynamics among tissues and cell populations over the course of infection. Our findings highlight the major role for CD8 lymphocytes in prolonging disease progression through continual control of SIV subpopulations from various anatomical compartments and the potential for greater independent viral evolutionary behavior among these compartments in response to immune modulation. Although developments in combined antiretroviral therapy (cART) strategies have successfully prolonged the time to AIDS onset in HIV-1-infected individuals, a functional cure has yet to be found. Improvement of drug interventions for a virus that is able to infect a wide range of tissues and cell types requires a thorough understanding of viral adaptation and infection dynamics within this target milieu. Although it is difficult to accomplish in the human host, longitudinal sampling of multiple anatomical locations is readily accessible in the SIV-infected macaque models of neuro-AIDS. The significance of our research is in identifying the impact of immune modulation, through differing immune selective pressures, on viral evolutionary behavior in a multitude of anatomical compartments. The results provide evidence encouraging the development of a more sophisticated model that considers a network of individual viral subpopulations within the host, with differing infection and transmission dynamics, which is necessary for more effective treatment strategies.
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http://dx.doi.org/10.1128/JVI.01162-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5686727PMC
December 2017

Application of a Novel CD206+ Macrophage-Specific Arterial Imaging Strategy in HIV-Infected Individuals.

J Infect Dis 2017 04;215(8):1264-1269

Program in Nutritional Metabolism and.

Background: The ability to noninvasively assess arterial CD206+ macrophages may lead to improved understanding of human immunodeficiency virus (HIV)-associated cardiovascular disease.

Methods: We trialed a novel macrophage-specific arterial imaging technique.

Results: We demonstrated colocalization between technetium Tc 99m tilmanocept (99mTc-tilmanocept) and CD206+ macrophages ex vivo. In vivo application of 99mTc-tilmanocept single-photon emission computed tomography/computed tomography revealed high-level 99mTc-tilmanocept uptake across 20.4% of the aortic surface volume among HIV-infected subjects, compared with 4.3% among non-HIV-infected subjects (P = .009). Among all subjects, aortic high-level 99mTc-tilmanocept uptake was related to noncalcified aortic plaque volume (r = 0.87; P = .003) on computed tomographic angiography, and this relationship held when we controlled for HIV status.

Conclusion: These first-in-human data introduce a novel macrophage-specific arterial imaging technique in HIV.

Clinical Trials Registration: NCT02542371.
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http://dx.doi.org/10.1093/infdis/jix095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853590PMC
April 2017

Evolution of Neuroadaptation in the Periphery and Purifying Selection in the Brain Contribute to Compartmentalization of Simian Immunodeficiency Virus (SIV) in the Brains of Rhesus Macaques with SIV-Associated Encephalitis.

J Virol 2016 07 10;90(13):6112-6126. Epub 2016 Jun 10.

Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, Florida, USA

Unlabelled: The emergence of a distinct subpopulation of human or simian immunodeficiency virus (HIV/SIV) sequences within the brain (compartmentalization) during infection is hypothesized to be linked to AIDS-related central nervous system (CNS) neuropathology. However, the exact evolutionary mechanism responsible for HIV/SIV brain compartmentalization has not been thoroughly investigated. Using extensive viral sampling from several different peripheral tissues and cell types and from three distinct regions within the brain from two well-characterized rhesus macaque models of the neurological complications of HIV infection (neuroAIDS), we have been able to perform in-depth evolutionary analyses that have been unattainable in HIV-infected subjects. The results indicate that, despite multiple introductions of virus into the brain over the course of infection, brain sequence compartmentalization in macaques with SIV-associated CNS neuropathology likely results from late viral entry of virus that has acquired through evolution in the periphery sufficient adaptation for the distinct microenvironment of the CNS.

Importance: HIV-associated neurocognitive disorders remain prevalent among HIV type 1-infected individuals, whereas our understanding of the critical components of disease pathogenesis, such as virus evolution and adaptation, remains limited. Building upon earlier findings of specific viral subpopulations in the brain, we present novel yet fundamental results concerning the evolutionary patterns driving this phenomenon in two well-characterized animal models of neuroAIDS and provide insight into the timing of entry of virus into the brain and selective pressure associated with viral adaptation to this particular microenvironment. Such knowledge is invaluable for therapeutic strategies designed to slow or even prevent neurocognitive impairment associated with AIDS.
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http://dx.doi.org/10.1128/JVI.00137-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907235PMC
July 2016

Evolutionary and Functional Analysis of Old World Primate TRIM5 Reveals the Ancient Emergence of Primate Lentiviruses and Convergent Evolution Targeting a Conserved Capsid Interface.

PLoS Pathog 2015 Aug 20;11(8):e1005085. Epub 2015 Aug 20.

Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America.

The widespread distribution of lentiviruses among African primates, and the lack of severe pathogenesis in many of these natural reservoirs, are taken as evidence for long-term co-evolution between the simian immunodeficiency viruses (SIVs) and their primate hosts. Evidence for positive selection acting on antiviral restriction factors is consistent with virus-host interactions spanning millions of years of primate evolution. However, many restriction mechanisms are not virus-specific, and selection cannot be unambiguously attributed to any one type of virus. We hypothesized that the restriction factor TRIM5, because of its unique specificity for retrovirus capsids, should accumulate adaptive changes in a virus-specific fashion, and therefore, that phylogenetic reconstruction of TRIM5 evolution in African primates should reveal selection by lentiviruses closely related to modern SIVs. We analyzed complete TRIM5 coding sequences of 22 Old World primates and identified a tightly-spaced cluster of branch-specific adaptions appearing in the Cercopithecinae lineage after divergence from the Colobinae around 16 million years ago. Functional assays of both extant TRIM5 orthologs and reconstructed ancestral TRIM5 proteins revealed that this cluster of adaptations in TRIM5 specifically resulted in the ability to restrict Cercopithecine lentiviruses, but had no effect (positive or negative) on restriction of other retroviruses, including lentiviruses of non-Cercopithecine primates. The correlation between lineage-specific adaptations and ability to restrict viruses endemic to the same hosts supports the hypothesis that lentiviruses closely related to modern SIVs were present in Africa and infecting the ancestors of Cercopithecine primates as far back as 16 million years ago, and provides insight into the evolution of TRIM5 specificity.
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http://dx.doi.org/10.1371/journal.ppat.1005085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4546234PMC
August 2015

High expression levels of BLyS/BAFF by blood dendritic cells and granulocytes are associated with B-cell dysregulation in SIV-infected rhesus macaques.

PLoS One 2015 24;10(6):e0131513. Epub 2015 Jun 24.

Laboratoire d'immunogénétique, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada; Département de Microbiologie, Infectiologie et Immunologie de l'Université de Montréal, Montréal, Canada.

Dendritic cells (DCs) modulate B-cell survival and differentiation, mainly through production of growth factors such as B lymphocyte stimulator (BLyS/BAFF). In recent longitudinal studies involving HIV-1-infected individuals with different rates of disease progression, we have shown that DCs were altered in number and phenotype in the context of HIV-1 disease progression and B-cell dysregulations were associated with increased BLyS/BAFF expression in plasma and by blood myeloid DCs (mDCs) in rapid and classic progressors but not in HIV-1-elite controllers (EC). Suggesting that the extent to which HIV-1 disease progression is controlled may be linked to BLyS/BAFF expression status and the capacity to orchestrate B-cell responses. Herein, longitudinal analyses of simian immunodeficiency virus (SIV)-infected rhesus macaques also revealed increased expression of BLyS/BAFF by blood mDCs as soon as day 8 and throughout infection. Strikingly, granulocytes presented the highest BLyS/BAFF expression profile in the blood of SIV-infected macaques. BLyS/BAFF levels were also increased in plasma and correlated with viral loads. Consequently, these SIV-infected animals had plasma hyperglobulinemia and reduced blood B-cell numbers with altered population frequencies. These data underscore that BLyS/BAFF is associated with immune dysregulation in SIV-infected rhesus macaques and suggest that BLyS/BAFF is a key regulator of immune activation that is highly conserved among primates. These findings emphasize the potential importance of this SIV-infected primate model to test whether blocking excess BLyS/BAFF has an effect on the overall inflammatory burden and immune restoration.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0131513PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4479440PMC
April 2016

Tracking the Emergence of Host-Specific Simian Immunodeficiency Virus env and nef Populations Reveals nef Early Adaptation and Convergent Evolution in Brain of Naturally Progressing Rhesus Macaques.

J Virol 2015 Aug 3;89(16):8484-96. Epub 2015 Jun 3.

Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, Florida, USA Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA

Unlabelled: While a clear understanding of the events leading to successful establishment of host-specific viral populations and productive infection in the central nervous system (CNS) has not yet been reached, the simian immunodeficiency virus (SIV)-infected rhesus macaque provides a powerful model for the study of human immunodeficiency virus (HIV) intrahost evolution and neuropathogenesis. The evolution of the gp120 and nef genes, which encode two key proteins required for the establishment and maintenance of infection, was assessed in macaques that were intravenously inoculated with the same viral swarm and allowed to naturally progress to simian AIDS and potential SIV-associated encephalitis (SIVE). Longitudinal plasma samples and immune markers were monitored until terminal illness. Single-genome sequencing was employed to amplify full-length env through nef transcripts from plasma over time and from brain tissues at necropsy. nef sequences diverged from the founder virus faster than gp120 diverged. Host-specific sequence populations were detected in nef (~92 days) before they were detected in gp120 (~182 days). At necropsy, similar brain nef sequences were found in different macaques, indicating convergent evolution, while gp120 brain sequences remained largely host specific. Molecular clock and selection analyses showed weaker clock-like behavior and stronger selection pressure in nef than in gp120, with the strongest nef selection in the macaque with SIVE. Rapid nef diversification, occurring prior to gp120 diversification, indicates that early adaptation of nef in the new host is essential for successful infection. Moreover, the convergent evolution of nef sequences in the CNS suggests a significant role for nef in establishing neurotropic strains.

Importance: The SIV-infected rhesus macaque model closely resembles HIV-1 immunopathogenesis, neuropathogenesis, and disease progression in humans. Macaques were intravenously infected with identical viral swarms to investigate evolutionary patterns in the gp120 and nef genes leading to the emergence of host-specific viral populations and potentially linked to disease progression. Although each macaque exhibited unique immune profiles, macaque-specific nef sequences evolving under selection were consistently detected in plasma samples at 3 months postinfection, significantly earlier than in gp120 macaque-specific sequences. On the other hand, nef sequences in brain tissues, collected at necropsy of two animals with detectable infection in the central nervous system (CNS), revealed convergent evolution. The results not only indicate that early adaptation of nef in the new host may be essential for successful infection, but also suggest that specific nef variants may be required for SIV to efficiently invade CNS macrophages and/or enhance macrophage migration, resulting in HIV neuropathology.
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http://dx.doi.org/10.1128/JVI.01010-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524235PMC
August 2015

Distinct phenotype, longitudinal changes of numbers and cell-associated virus in blood dendritic cells in SIV-infected CD8-lymphocyte depleted macaques.

PLoS One 2015 27;10(4):e0119764. Epub 2015 Apr 27.

Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America.

Loss of circulating CD123+ plasmacytoid dendritic cells (pDCs) during HIV infection is well established. However, changes of myeloid DCs (mDCs) are ambiguous since they are studied as a homogeneous CD11c+ population despite phenotypic and functional heterogeneity. Heterogeneity of CD11c+ mDCs in primates is poorly described in HIV and SIV infection. Using multiparametric flow cytometry, we monitored longitudinally cell number and cell-associated virus of CD123+ pDCs and non-overlapping subsets of CD1c+ and CD16+ mDCs in SIV-infected CD8-depleted rhesus macaques. The numbers of all three DC subsets were significantly decreased by 8 days post-infection. Whereas CD123+ pDCs were persistently depleted, numbers of CD1c+ and CD16+ mDCs rebounded. Numbers of CD1c+ mDCs significantly increased by 3 weeks post-infection while numbers of CD16+ mDCs remained closer to pre-infection levels. We found similar changes in the numbers of all three DC subsets in CD8 depleted animals as we found in animals that were SIV infected animals that were not CD8 lymphocyte depleted. CD16+ mDCs and CD123+ pDCs but not CD1c+ mDCs were significantly decreased terminally with AIDS. All DC subsets harbored SIV RNA as early as 8 days and then throughout infection. However, SIV DNA was only detected in CD123+ pDCs and only at 40 days post-infection consistent with SIV RNA, at least in mDCs, being surface-bound. Altogether our data demonstrate that SIV infection differently affects CD1c+ and CD16+ mDCs where CD16+ but not CD1c+ mDCs are depleted and might be differentially regulated in terminal AIDS. Finally, our data underline the importance of studying CD1c+ and CD16+ mDCs as discrete populations, and not as total CD11c+ mDCs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0119764PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4410956PMC
April 2016

Anti-α4 antibody treatment blocks virus traffic to the brain and gut early, and stabilizes CNS injury late in infection.

PLoS Pathog 2014 Dec 11;10(12):e1004533. Epub 2014 Dec 11.

Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America.

Four SIV-infected monkeys with high plasma virus and CNS injury were treated with an anti-α4 blocking antibody (natalizumab) once a week for three weeks beginning on 28 days post-infection (late). Infection in the brain and gut were quantified, and neuronal injury in the CNS was assessed by MR spectroscopy, and compared to controls with AIDS and SIV encephalitis. Treatment resulted in stabilization of ongoing neuronal injury (NAA/Cr by 1H MRS), and decreased numbers of monocytes/macrophages and productive infection (SIV p28+, RNA+) in brain and gut. Antibody treatment of six SIV infected monkeys at the time of infection (early) for 3 weeks blocked monocyte/macrophage traffic and infection in the CNS, and significantly decreased leukocyte traffic and infection in the gut. SIV - RNA and p28 was absent in the CNS and the gut. SIV DNA was undetectable in brains of five of six early treated macaques, but proviral DNA in guts of treated and control animals was equivalent. Early treated animals had low-to-no plasma LPS and sCD163. These results support the notion that monocyte/macrophage traffic late in infection drives neuronal injury and maintains CNS viral reservoirs and lesions. Leukocyte traffic early in infection seeds the CNS with virus and contributes to productive infection in the gut. Leukocyte traffic early contributes to gut pathology, bacterial translocation, and activation of innate immunity.
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http://dx.doi.org/10.1371/journal.ppat.1004533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4263764PMC
December 2014

Spatiotemporal dynamics of simian immunodeficiency virus brain infection in CD8+ lymphocyte-depleted rhesus macaques with neuroAIDS.

J Gen Virol 2014 Dec 9;95(Pt 12):2784-2795. Epub 2014 Sep 9.

Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.

Despite the success of combined antiretroviral therapy in controlling viral replication in human immunodeficiency virus (HIV)-infected individuals, HIV-associated neurocognitive disorders, commonly referred to as neuroAIDS, remain a frequent and poorly understood complication. Infection of CD8(+) lymphocyte-depleted rhesus macaques with the SIVmac251 viral swarm is a well-established rapid disease model of neuroAIDS that has provided critical insight into HIV-1-associated neurocognitive disorder onset and progression. However, no studies so far have characterized in depth the relationship between intra-host viral evolution and pathogenesis in this model. Simian immunodeficiency virus (SIV) env gp120 sequences were obtained from six infected animals. Sequences were sampled longitudinally from several lymphoid and non-lymphoid tissues, including individual lobes within the brain at necropsy, for four macaques; two animals were sacrificed at 21 days post-infection (p.i.) to evaluate early viral seeding of the brain. Bayesian phylodynamic and phylogeographic analyses of the sequence data were used to ascertain viral population dynamics and gene flow between peripheral and brain tissues, respectively. A steady increase in viral effective population size, with a peak occurring at ~50-80 days p.i., was observed across all longitudinally monitored macaques. Phylogeographic analysis indicated continual viral seeding of the brain from several peripheral tissues throughout infection, with the last migration event before terminal illness occurring in all macaques from cells within the bone marrow. The results strongly supported the role of infected bone marrow cells in HIV/SIV neuropathogenesis. In addition, our work demonstrated the applicability of Bayesian phylogeography to intra-host studies in order to assess the interplay between viral evolution and pathogenesis.
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http://dx.doi.org/10.1099/vir.0.070318-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4233634PMC
December 2014

Soluble CD163 made by monocyte/macrophages is a novel marker of HIV activity in early and chronic infection prior to and after anti-retroviral therapy.

J Infect Dis 2011 Jul;204(1):154-63

Department of Biology, Boston College, Chestnut Hill, MA, USA.

CD163, a monocyte- and macrophage-specific scavenger receptor, is shed during activation as soluble CD163 (sCD163). We have previously demonstrated that monocyte expansion from bone marrow with simian immunodeficiency virus (SIV) infection correlated with plasma sCD163, the rate of AIDS progression, and the severity of macrophage-mediated pathogenesis. Here, we examined sCD163 in human immunodeficiency virus (HIV) infection. sCD163 was elevated in the plasma of individuals with chronic HIV infection (>1 year in duration), compared with HIV-seronegative individuals. With effective antiretroviral therapy (ART), sCD163 levels decreased in parallel with HIV RNA levels but did not return to HIV-seronegative levels, suggesting the presence of residual monocyte/macrophage activation even with plasma viral loads below the limit of detection. In individuals with early HIV infection (≤1 year in duration), effective ART resulted in decreased sCD163 levels that were comparable to levels in HIV-seronegative individuals. sCD163 levels in plasma were positively correlated with the percentage of CD14+CD16+ monocytes and activated CD8+HLA-DR+CD38+ T lymphocytes and were inversely correlated with CD163 expression on CD14+CD16+ monocytes. With ART interruption in subjects with early HIV infection, sCD163 and plasma virus levels spiked but rapidly returned to baseline with reinitiation of ART. This study points to the utility of monocyte- and macrophage-derived sCD163 as a marker of HIV activity that links viral replication with monocyte and macrophage activation. These observations underscore the significance of monocyte and macrophage immune responses with HIV pathogenesis.
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http://dx.doi.org/10.1093/infdis/jir214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3105035PMC
July 2011

Minocycline inhibition of monocyte activation correlates with neuronal protection in SIV neuroAIDS.

PLoS One 2011 Apr 6;6(4):e18688. Epub 2011 Apr 6.

Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America.

Background: Minocycline is a tetracycline antibiotic that has been proposed as a potential conjunctive therapy for HIV-1 associated cognitive disorders. Precise mechanism(s) of minocycline's functions are not well defined.

Methods: Fourteen rhesus macaques were SIV infected and neuronal metabolites measured by proton magnetic resonance spectroscopy ((1)H MRS). Seven received minocycline (4 mg/kg) daily starting at day 28 post-infection (pi). Monocyte expansion and activation were assessed by flow cytometry, cell traffic to lymph nodes, CD16 regulation, viral replication, and cytokine production were studied.

Results: Minocycline treatment decreased plasma virus and pro-inflammatory CD14+CD16+ and CD14(lo)CD16+ monocytes, and reduced their expression of CD11b, CD163, CD64, CCR2 and HLA-DR. There was reduced recruitment of monocyte/macrophages and productively infected cells in axillary lymph nodes. There was an inverse correlation between brain NAA/Cr (neuronal injury) and circulating CD14+CD16+ and CD14(lo)CD16+ monocytes. Minocycline treatment in vitro reduced SIV replication CD16 expression on activated CD14+CD16+ monocytes, and IL-6 production by monocytes following LPS stimulation.

Conclusion: Neuroprotective effects of minocycline are due in part to reduction of activated monocytes, monocyte traffic. Mechanisms for these effects include CD16 regulation, reduced viral replication, and inhibited immune activation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0018688PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071838PMC
April 2011

Immunophenotyping of lymphocyte, monocyte and dendritic cell subsets in normal rhesus macaques by 12-color flow cytometry: clarification on DC heterogeneity.

J Immunol Methods 2010 Aug 30;360(1-2):119-28. Epub 2010 Jun 30.

Department of Biology, Boston College, Higgins Hall 468, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA.

Monitoring changes in rhesus macaque immune cell populations during infectious disease is crucial. The aim of this work was to simultaneously analyze the phenotype of rhesus macaque lymphocyte, monocyte and dendritic cell (DC) subsets using a single 12-color flow cytometry panel. Blood from healthy non-infected rhesus macaques was labeled with a cocktail of 12 antibodies. Data were compared to three smaller lineage specific panels and absolute and relative percentages of cells were compared. Our 12-color panel allows for the identification of the following major subsets: CD4+ and CD8+ T lymphocytes, B lymphocytes, natural killer (NK) cells, natural killer T (NKT) cells, monocyte subsets and four non-overlapping Lin-HLA-DR+ cell subsets: CD34+ hematopoietic stem cells, CD11c- CD123+ plasmacytoid DC, CD11c+ CD16+ and CD11c(-)(/dim) CD1c+ myeloid DC. The development of a multiparameter flow cytometry panel will allow for simultaneous enumeration of mature lymphocyte, NK cells, monocyte and DC subsets. Studying these major players of the immune system in one panel may give us a broader view of the immune response during SIV infection and the ability to better define the role of each of these individual cell types in the pathogenesis of AIDS.
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http://dx.doi.org/10.1016/j.jim.2010.06.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2930593PMC
August 2010

Proton magnetic resonance spectroscopy reveals neuroprotection by oral minocycline in a nonhuman primate model of accelerated NeuroAIDS.

PLoS One 2010 May 7;5(5):e10523. Epub 2010 May 7.

AA Martinos Center for Biomedical Imaging and Neuroradiology Division, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.

Background: Despite the advent of highly active anti-retroviral therapy (HAART), HIV-associated neurocognitive disorders continue to be a significant problem. In efforts to understand and alleviate neurocognitive deficits associated with HIV, we used an accelerated simian immunodeficiency virus (SIV) macaque model of NeuroAIDS to test whether minocycline is neuroprotective against lentiviral-induced neuronal injury.

Methodology/principal Findings: Eleven rhesus macaques were infected with SIV, depleted of CD8+ lymphocytes, and studied until eight weeks post inoculation (wpi). Seven animals received daily minocycline orally beginning at 4 wpi. Neuronal integrity was monitored in vivo by proton magnetic resonance spectroscopy and post-mortem by immunohistochemistry for synaptophysin (SYN), microtubule-associated protein 2 (MAP2), and neuronal counts. Astrogliosis and microglial activation were quantified by measuring glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (IBA-1), respectively. SIV infection followed by CD8+ cell depletion induced a progressive decline in neuronal integrity evidenced by declining N-acetylaspartate/creatine (NAA/Cr), which was arrested with minocycline treatment. The recovery of this ratio was due to increases in NAA, indicating neuronal recovery, and decreases in Cr, likely reflecting downregulation of glial cell activation. SYN, MAP2, and neuronal counts were found to be higher in minocycline-treated animals compared to untreated animals while GFAP and IBA-1 expression were decreased compared to controls. CSF and plasma viral loads were lower in MN-treated animals.

Conclusions/significance: In conclusion, oral minocycline alleviates neuronal damage induced by the AIDS virus.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0010523PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866543PMC
May 2010

Evaluation of a 12-color flow cytometry panel to study lymphocyte, monocyte, and dendritic cell subsets in humans.

Cytometry A 2010 May;77(5):410-9

Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA.

Monitoring changes in human immune cell populations such as lymphocytes, monocytes, and dendritic cells (DCs) during infectious diseases like human immunodeficiency virus (HIV) is crucial. However, difficulties to identify rare or heterogeneous cell populations can be limiting. For example, to accurately measure DC subsets, eight flow cytometry parameters are ideal. The aim of this work was to analyze the phenotype of human lymphocyte, monocyte, and DC subsets using a single 12-color flow cytometry panel. After erythrocyte lysis, blood from healthy human volunteers was washed and labeled with a cocktail of 12 antibodies. Samples were analyzed on a Becton-Dickinson FACSAria equipped with three lasers. Data were compared with lineage-specific panels using 5-8 Ab combinations per lineage. Acquired data were analyzed using FlowJo software. Our 12-color panel allows for the identification of the following major subsets of circulating cells in a single tube: CD4+ and CD8+ T lymphocytes, B lymphocytes, NK cells, NKT cells, monocyte subsets (CD14 and/or CD16), and five nonoverlapping HLA-DR+Lin- subsets: CD34+ hematopoietic stem cells, CD123+ plasmacytoid DC, and three subsets of CD11c+ myeloid DC expressing either CD16, CD1c (BDCA-1), or CD141 (BDCA-3). We have developed a single flow cytometry panel that allows for simultaneous detection of the lymphocyte and monocyte cell populations and all known DC subsets. Studying these major players of the immune system in one single panel may give us a broader view of the immune response during HIV infection and the ability to better define the role of individual cell types in Acquired Immune Deficiency Syndrome (AIDS) pathogenesis. (c) 2010 International Society for Advancement of Cytometry.
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http://dx.doi.org/10.1002/cyto.a.20859DOI Listing
May 2010

Monocyte heterogeneity underlying phenotypic changes in monocytes according to SIV disease stage.

J Leukoc Biol 2010 Apr 20;87(4):557-67. Epub 2009 Oct 20.

Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Infection by HIV is associated with the expansion of monocytes expressing CD16 antigens, but the significance of this in HIV pathogenesis is largely unknown. In rhesus macaques, at least three subpopulations of blood monocytes were identified based on their expression of CD14 and CD16: CD14(high)CD16(-), CD14(high)CD16(low), and CD14(low)CD16(high). The phenotypes and functions of these subpopulations, including CD16(+) monocytes, were investigated in normal, uninfected rhesus macaques and macaques that were infected with SIV or chimeric SHIV. To assess whether these different monocyte subpopulations expand or contract in AIDS pathogenesis, we conducted a cross-sectional study of 54 SIV- or SHIV-infected macaques and 48 uninfected controls. The absolute numbers of monocyte populations were examined in acutely infected animals, chronically infected animals with no detectable plasma virus RNA, chronically infected animals with detectable plasma virus RNA, and animals that died with AIDS. The absolute numbers of CD14(high)CD16(low) and CD14(low)CD16(high) monocytes were elevated significantly in acutely infected animals and chronically infected animals with detectable plasma virus RNA compared with uninfected controls. Moreover, a significant, positive correlation was evident between the number of CD14(high)CD16(low) or CD14(low)CD16(high) monocytes and plasma viral load in the infected cohort. These data show the dynamic changes of blood monocytes, most notably, CD14(high)CD16(low) monocytes during lentiviral infection, which are specific to disease stage.
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http://dx.doi.org/10.1189/jlb.0209082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858301PMC
April 2010

Dominant CD8+ T-lymphocyte responses suppress expansion of vaccine-elicited subdominant T lymphocytes in rhesus monkeys challenged with pathogenic simian-human immunodeficiency virus.

J Virol 2009 Oct 29;83(19):10028-35. Epub 2009 Jul 29.

Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, E/CLS Room 1043, Boston, Massachusetts 02215, USA.

Emerging data suggest that a cytotoxic T-lymphocyte response against a diversity of epitopes confers greater protection against a human immunodeficiency virus/simian immunodeficiency virus infection than does a more focused response. To facilitate the creation of vaccine strategies that will generate cellular immune responses with the greatest breadth, it will be important to understand the mechanisms employed by the immune response to regulate the relative magnitudes of dominant and nondominant epitope-specific cellular immune responses. In this study, we generated dominant Gag p11C- and subdominant Env p41A-specific CD8(+) T-lymphocyte responses in Mamu-A*01(+) rhesus monkeys through vaccination with plasmid DNA and recombinant adenovirus encoding simian-human immunodeficiency virus (SHIV) proteins. Infection of vaccinated Mamu-A*01(+) rhesus monkeys with a SHIV Gag Deltap11C mutant virus generated a significantly increased expansion of the Env p41A-specific CD8(+) T-lymphocyte response in the absence of secondary Gag p11C-specific CD8(+) T-lymphocyte responses. These results indicate that the presence of the Gag p11C-specific CD8(+) T-lymphocyte response following virus challenge may exert suppressive effects on primed Env p41A-specific CD8(+) T-lymphocyte responses. These findings suggest that immunodomination exerted by dominant responses during SHIV infection may diminish the breadth of recall responses primed during vaccination.
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http://dx.doi.org/10.1128/JVI.01015-09DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2748023PMC
October 2009

Diverse cross-reactive potential and Vbeta gene usage of an epitope-specific cytotoxic T-lymphocyte population in monkeys immunized with diverse human immunodeficiency virus type 1 Env immunogens.

J Virol 2009 Oct 29;83(19):9803-12. Epub 2009 Jul 29.

Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, Massachusetts 02215, USA.

An ideal human immunodeficiency virus type 1 (HIV-1) vaccine would elicit potent cellular and humoral immune responses that recognize diverse strains of the virus. In the present study, combined methodologies (flow cytometry, Vbeta repertoire analysis, and complementarity-determining region 3 sequencing) were used to determine the clonality of CD8(+) T lymphocytes taking part in the recognition of variant epitope peptides elicited in Mamu-A*01-positive rhesus monkeys immunized with vaccines encoding diverse HIV-1 envelopes (Envs). Monkeys immunized with clade B Envs generated CD8(+) T lymphocytes that cross-recognized both clade B- and clade C-p41A epitope peptides using a large degree of diversity in Vbeta gene usage. However, with two monkeys immunized with clade C Env, one monkey exhibited p41A-specific cytotoxic T-lymphocytes (CTL) with the capacity for cross-recognition of variant epitopes, while the other monkey did not. These studies demonstrate that the cross-reactive potential of variant p41A epitope peptide-specific CTL populations can differ between monkeys that share the same restricting major histocompatibility complex class I molecule and receive the same vaccine immunogens.
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http://dx.doi.org/10.1128/JVI.00776-09DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2748000PMC
October 2009

Detection of JC virus DNA and proteins in the bone marrow of HIV-positive and HIV-negative patients: implications for viral latency and neurotropic transformation.

J Infect Dis 2009 Mar;199(6):881-8

Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.

Background: We sought to determine the prevalence of JC virus (JCV) in bone marrow samples from human immunodeficiency virus (HIV)-positive and HIV-negative patients and to determine whether bone marrow is a site of latency and neurotropic transformation of JCV, the agent of progressive multifocal leukoencephalopathy (PML).

Methods: We collected bone marrow aspirates, archival bone marrow samples, and blood and urine samples from 75 HIV-negative and 47 HIV-positive patients without PML as well as bone marrow and urine or kidney samples from 8 HIV-negative and 15 HIV-positive patients with PML. Samples were tested for JCV DNA by quantitative polymerase chain reaction and for JCV protein expression by immunohistochemical analysis. JCV regulatory regions (RRs) were characterized by sequencing.

Results: JCV DNA was detected in bone marrow samples from 10 (13%) of 75 and 22 (47%) of 47 of the HIV-negative and HIV-positive patients without PML, respectively, compared with 3 (38%) of 8 and 4 (27%) of 15 of the HIV-negative and HIV-positive patients with PML. JCV DNA (range, 2-1081 copies/microg of cellular DNA) was detected in multiple leukocyte subpopulations of blood and bone marrow samples. JCV large T antigen, but not VP1 capsid protein, was expressed in bone marrow plasma cells. Bone marrow JCV RR sequences were similar to those usually found in the brains of patients with PML.

Conclusions: Bone marrow is an important reservoir and a possible site of neurotropic transformation for JCV.
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http://dx.doi.org/10.1086/597117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2893283PMC
March 2009

Acute Schistosoma mansoni infection increases susceptibility to systemic SHIV clade C infection in rhesus macaques after mucosal virus exposure.

PLoS Negl Trop Dis 2008 Jul 23;2(7):e265. Epub 2008 Jul 23.

Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America.

Background: Individuals living in sub-Saharan Africa represent 10% of the world's population but almost 2/3 of all HIV-1/AIDS cases. The disproportionate HIV-1 infection rates in this region may be linked to helminthic parasite infections that affect many individuals in the developing world. However, the hypothesis that parasite infection increases an individual's susceptibility to HIV-1 has never been prospectively tested in a relevant in vivo model.

Methodology/principal Findings: We measured whether pre-existing infection of rhesus monkeys with a parasitic worm would facilitate systemic infection after mucosal AIDS virus exposure. Two groups of animals, one consisting of normal monkeys and the other harboring Schistosoma mansoni, were challenged intrarectally with decreasing doses of R5-tropic clade C simian-human immunodeficiency virus (SHIV-C). Systemic infection occurred in parasitized monkeys at viral doses that remained sub-infectious in normal hosts. In fact, the 50% animal infectious (AID(50)) SHIV-C dose was 17-fold lower in parasitized animals compared to controls (P<0.001). Coinfected animals also had significantly higher peak viral RNA loads than controls (P<0.001), as well as increased viral replication in CD4(+) central memory cells (P = 0.03).

Conclusions/significance: Our data provide the first direct evidence that acute schistosomiasis significantly increases the risk of de novo AIDS virus acquisition, and the magnitude of the effect suggests that control of helminth infections may be a useful public health intervention to help decrease the spread of HIV-1.
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http://dx.doi.org/10.1371/journal.pntd.0000265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2447882PMC
July 2008

Microbial translocation is associated with increased monocyte activation and dementia in AIDS patients.

PLoS One 2008 Jun 25;3(6):e2516. Epub 2008 Jun 25.

Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, United States of America.

Elevated plasma lipopolysaccharide (LPS), an indicator of microbial translocation from the gut, is a likely cause of systemic immune activation in chronic HIV infection. LPS induces monocyte activation and trafficking into brain, which are key mechanisms in the pathogenesis of HIV-associated dementia (HAD). To determine whether high LPS levels are associated with increased monocyte activation and HAD, we obtained peripheral blood samples from AIDS patients and examined plasma LPS by Limulus amebocyte lysate (LAL) assay, peripheral blood monocytes by FACS, and soluble markers of monocyte activation by ELISA. Purified monocytes were isolated by FACS sorting, and HIV DNA and RNA levels were quantified by real time PCR. Circulating monocytes expressed high levels of the activation markers CD69 and HLA-DR, and harbored low levels of HIV compared to CD4(+) T-cells. High plasma LPS levels were associated with increased plasma sCD14 and LPS-binding protein (LBP) levels, and low endotoxin core antibody levels. LPS levels were higher in HAD patients compared to control groups, and were associated with HAD independently of plasma viral load and CD4 counts. LPS levels were higher in AIDS patients using intravenous heroin and/or ethanol, or with Hepatitis C virus (HCV) co-infection, compared to control groups. These results suggest a role for elevated LPS levels in driving monocyte activation in AIDS, thereby contributing to the pathogenesis of HAD, and provide evidence that cofactors linked to substance abuse and HCV co-infection influence these processes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0002516PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2424175PMC
June 2008

BKV and JCV large T antigen-specific CD8+ T cell response in HLA A*0201+ kidney transplant recipients with polyomavirus nephropathy and patients with progressive multifocal leukoencephalopathy.

J Clin Virol 2008 Jun 4;42(2):198-202. Epub 2008 Mar 4.

Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.

Background: BK virus (BKV), which causes polyomavirus-associated nephropathy (PVN) in kidney transplant recipients (KTx), has 75% homology with JC virus (JCV), the etiologic agent of progressive multifocal leukoencephalopathy (PML). The large T-antigen (T-ag) is the main regulatory protein of polyomaviruses that is expressed early in the viral cycle.

Objectives: To characterize epitopes of BKV and JCV T-ag recognized by CD8+ T-cells and explore the role of these cells in containing polyomavirus infection.

Study Design: We tested peripheral blood mononuclear cells of HLA A*0201+ BKV- and JCV-seropositive individuals, including patients with active BKV or JCV infection and healthy control subjects in a cross-sectional study.

Results: CD8+ T-cells that recognized the nonamer BKV Tp579, which is identical to JCV Tp578, were detected by tetramer staining in 10/13 (77%) healthy individuals, 3/10 (30%) KTx/PVN, and 4/9 (44%) patients with PML and/or HIV-infection. Conversely, BKV Tp398- and Tp410-specific CD8+ T cells were detected in 3/13 (23%) and 1/13 (8%) healthy individuals only.

Conclusion: These data suggest that, as it is the case for the VP1 protein, the same population of CD8+ T-cells may recognize epitopes located on the BKV and JCV T protein. The overall cellular immune response against polyomavirus T-ag, however, is lower than against the VP1 protein and is more frequently detected in healthy individuals than in patients with active BKV or JCV infection.
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http://dx.doi.org/10.1016/j.jcv.2008.01.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2678795PMC
June 2008

Clonal focusing of epitope-specific CD8+ T lymphocytes in rhesus monkeys following vaccination and simian-human immunodeficiency virus challenge.

J Virol 2008 Jan 31;82(2):805-16. Epub 2007 Oct 31.

Beth Israel Deaconess Medical Center, Division of Viral Pathogenesis, 330 Brookline Ave., Boston, MA 02215, USA.

To afford the greatest possible immune protection, candidate human immunodeficiency virus (HIV) vaccines must generate diverse and long-lasting CD8(+) T lymphocyte responses. In the present study, we evaluate T-cell receptor Vbeta (variable region beta) gene usage and a CDR3 (complementarity-determining region 3) sequence to assess the clonality of epitope-specific CD8(+) T lymphocytes generated in rhesus monkeys following vaccination and simian-human immunodeficiency virus (SHIV) challenge. We found that vaccine-elicited epitope-specific CD8(+) T lymphocytes have a clonal diversity comparable to those cells generated in response to SHIV infection. Moreover, we show that the clonal diversity of vaccine-elicited CD8(+) T-lymphocyte responses is dictated by the epitope sequence and is not affected by the mode of antigen delivery to the immune system. Clonal CD8(+) T-lymphocyte populations persisted following boosting with different vectors, and these clonal cell populations could be detected for as long as 4 years after SHIV challenge. Finally, we show that the breadth of these epitope-specific T lymphocytes transiently focuses in response to intense SHIV replication. These observations demonstrate the importance of the initial immune response to SHIV, induced by vaccination or generated during primary infection, in determining the clonal diversity of cell-mediated immune responses and highlight the focusing of this clonal diversity in the setting of high viral loads. Circumventing this restricted CD8(+) T-lymphocyte clonal diversity may present a significant challenge in the development of an effective HIV vaccine strategy.
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http://dx.doi.org/10.1128/JVI.01038-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2224610PMC
January 2008

The impact of a boosting immunogen on the differentiation of secondary memory CD8+ T cells.

J Virol 2007 Dec 19;81(23):12793-802. Epub 2007 Sep 19.

Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02115, USA.

While recent studies have demonstrated that secondary CD8+ T cells develop into effector-memory cells, the impact of particular vaccine regimens on the elicitation of these cells remains poorly defined. In the present study we evaluated the effect of three different immunogens--recombinant vaccinia, recombinant adenovirus, and plasmid DNA--on the generation of memory cellular immune responses. We found that vectors that induce the rapid movement of CD8+ T cells into the memory compartment during a primary immune response also drive a rapid differentiation of these cells into effector-memory CD8+ T cells following a secondary immunization. In contrast, the functional profiles of both CD8+ and CD4+ T cells, assessed by measuring antigen-stimulated gamma interferon and interleukin-2 production, were not predominantly shaped by the boosting immunogen. We also demonstrated that the in vivo expression of antigen by recombinant vectors was brief following boosting immunization, suggesting that antigen persistence has a minimal impact on the differentiation of secondary CD8+ T cells. When used in heterologous or in homologous prime-boost combinations, these three vectors generated antigen-specific CD8+ T cells with different phenotypic profiles. Expression of the memory-associated molecule CD27 on effector CD8+ T cells decreased following heterologous but not homologous boosting, resulting in a phenotypic profile similar to that seen on primary CD8+ T cells. These data therefore suggest that the phenotype of secondary CD8+ T cells is determined predominantly by the boosting immunogen whereas the cytokine profile of these cells is shaped by both the priming and boosting immunogens.
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http://dx.doi.org/10.1128/JVI.01519-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2169130PMC
December 2007

Frequency and phenotype of JC virus-specific CD8+ T lymphocytes in the peripheral blood of patients with progressive multifocal leukoencephalopathy.

J Virol 2007 Apr 17;81(7):3361-8. Epub 2007 Jan 17.

Department of Neurology, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA.

JC virus (JCV)-specific CD8+ cytotoxic T lymphocytes (CTL) are associated with a favorable outcome in patients with progressive multifocal leukoencephalopathy (PML) and cross-recognize the polyomavirus BK virus (BKV). We sought to determine the frequency and phenotype in fresh blood of CD8+ T cells specific for two A*0201-restricted JCV epitopes, VP1(p36) and VP1(p100), and assess their impact on JC and BK viremia and viruria in 15 healthy subjects, eight human immunodeficiency virus-positive (HIV+) individuals, and nine HIV+ patients with PML (HIV+ PML patients) classified as survivors. After magnetic pre-enrichment of CD8+ T cells, epitope-specific cells ranged from 0.001% to 0.022% [corrected] by tetramer staining, with no significant difference among the three study groups. By use of seven-color flow cytometry, there was no predominant differentiation phenotype subset among JCV-specific CD8+ T cells in healthy individuals, HIV+ subjects, or HIV+ PML patients. However, in one HIV+ PML patient studied in the acute phase, there was a majority of activated effector memory cells. BKV DNA was undetectable in all blood samples by quantitative PCR, while a low JC viral load was found in the blood of only one HIV+ and two HIV+ PML patients. JCV and BKV DNA were detected in 33.3% and 13.3% of all urine samples, respectively, independent of the presence of JCV-specific CTL. The detection of JCV DNA in the urine was associated with the presence of a JCV VP1(p100) CTL response. Immunotherapies aiming at increasing the cellular immune response against JCV may be valuable in the treatment of HIV+ individuals with PML.
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http://dx.doi.org/10.1128/JVI.01809-06DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1866063PMC
April 2007

Contribution of T-cell receptor repertoire breadth to the dominance of epitope-specific CD8+ T-lymphocyte responses.

J Virol 2006 Dec 11;80(24):12032-40. Epub 2006 Oct 11.

Beth Israel Deaconess Medical Center, 41 Ave. Louis Pasteur, Boston, MA 02115, USA.

Dominant epitope-specific CD8(+) T-lymphocyte responses play a central role in controlling viral spread. We explored the basis for the development of this focused immune response in simian immunodeficiency virus (SIV)- and simian-human immunodeficiency virus (SHIV)-infected rhesus monkeys through the use of two dominant (p11C and p199RY) and two subdominant (p68A and p56A) epitopes. Using real-time PCR to quantitate T-cell receptor (TCR) variable region beta (Vbeta) family usage, we show that CD8(+) T-lymphocyte populations specific for dominant epitopes are characterized by a diverse Vbeta repertoire, whereas those specific for subdominant epitopes employ a dramatically more focused Vbeta repertoire. We also demonstrate that dominant epitope-specific CD8(+) T lymphocytes employ TCRs with multiple CDR3 lengths, whereas subdominant epitope-specific cells employ TCRs with a more restricted CDR3 length. Thus, the relative dominance of an epitope-specific CD8(+) T-lymphocyte response reflects the clonal diversity of that response. These findings suggest that the limited clonal repertoire of subdominant epitope-specific CD8(+) T-lymphocyte populations may limit the ability of these epitope-specific T-lymphocyte populations to expand and therefore limit the ability of these cell populations to contribute to the control of viral replication.
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http://dx.doi.org/10.1128/JVI.01479-06DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1676269PMC
December 2006