scholarly journals Simian Immunodeficiency Virus SIVrcm, a Unique CCR2-Tropic Virus, Selectively Depletes Memory CD4+ T Cells in Pigtailed Macaques through Expanded Coreceptor Usage In Vivo

2009 ◽  
Vol 83 (16) ◽  
pp. 7894-7908 ◽  
Author(s):  
Rajeev Gautam ◽  
Thaidra Gaufin ◽  
Isolde Butler ◽  
Aarti Gautam ◽  
Mary Barnes ◽  
...  
Keyword(s):  
T Cells ◽  
Simian Immunodeficiency Virus ◽  
Effector Memory ◽  
Coreceptor Usage ◽  
New Host ◽  
Viral Loads ◽  
Immunodeficiency Virus ◽  
Memory Cd4 T Cells

ABSTRACT Simian immunodeficiency virus SIVrcm, which naturally infects red-capped mangabeys (RCMs), is the only SIV that uses CCR2 as its main coreceptor due to the high frequency of a CCR5 deletion in RCMs. We investigated the dynamics of SIVrcm infection to identify specific pathogenic mechanisms associated with this major difference in SIV biology. Four pigtailed macaques (PTMs) were infected with SIVrcm, and infection was monitored for over 2 years. The dynamics of in vivo SIVrcm replication in PTMs was similar to that of other pathogenic and nonpathogenic lymphotropic SIVs. Plasma viral loads (VLs) peaked at 107 to 109 SIVrcm RNA copies/ml by day 10 postinoculation (p.i.). A viral set point was established by day 42 p.i. at 103 to 105 SIVrcm RNA copies/ml and lasted up to day 180 p.i., when plasma VLs decreased below the threshold of detection, with blips of viral replication during the follow-up. Intestinal SIVrcm replication paralleled that of plasma VLs. Up to 80% of the CD4+ T cells were depleted by day 28 p.i. in the gut. The most significant depletion (>90%) involved memory CD4+ T cells. Partial CD4+ T-cell restoration was observed in the intestine at later time points. Effector memory CD4+ T cells were the least restored. SIVrcm strains isolated from acutely infected PTMs used CCR2 coreceptor, as reported, but expansion of coreceptor usage to CCR4 was also observed. Selective depletion of effector memory CD4+ T cells is in contrast with predicted in vitro tropism of SIVrcm for macrophages and is probably due to expansion of coreceptor usage. Taken together, these findings emphasize the importance of understanding the selective forces driving viral adaptation to a new host.

scholarly journals Human Effector Memory CD4+ T Cells Directly Recognize Allogeneic Endothelial Cells In Vitro and In Vivo

2007 ◽  
Vol 179 (7) ◽  
pp. 4397-4404 ◽  
Author(s):  
Stephen L. Shiao ◽  
Nancy C. Kirkiles-Smith ◽  
Benjamin R. Shepherd ◽  
Jennifer M. McNiff ◽  
Edward J. Carr ◽  
...  
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
Cd4 T Cells ◽  
Effector Memory ◽  
Memory Cd4 T Cells

scholarly journals Gag-Specific Cellular Immunity DeterminesIn VitroViral Inhibition andIn VivoVirologic Control following Simian Immunodeficiency Virus Challenges of Vaccinated Rhesus Monkeys

2012 ◽  
Vol 86 (18) ◽  
pp. 9583-9589 ◽  
Author(s):  
Kathryn E. Stephenson ◽  
Hualin Li ◽  
Bruce D. Walker ◽  
Nelson L. Michael ◽  
Dan H. Barouch
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Rhesus Monkeys ◽  
Viral Inhibition ◽  
Viral Loads ◽  
Immunodeficiency Virus ◽  
Virologic Control ◽  
Cellular Immune ◽  
Hiv 1

A comprehensive vaccine for human immunodeficiency virus type 1 (HIV-1) would block HIV-1 acquisition as well as durably control viral replication in breakthrough infections. Recent studies have demonstrated that Env is required for a vaccine to protect against acquisition of simian immunodeficiency virus (SIV) in vaccinated rhesus monkeys, but the antigen requirements for virologic control remain unclear. Here, we investigate whether CD8+T lymphocytes from vaccinated rhesus monkeys mediate viral inhibitionin vitroand whether these responses predict virologic control following SIV challenge. We observed that CD8+lymphocytes from 23 vaccinated rhesus monkeys inhibited replication of SIVin vitro. Moreover, the magnitude of inhibition prior to challenge was inversely correlated with set point SIV plasma viral loads after challenge. In addition, CD8 cell-mediated viral inhibition in vaccinated rhesus monkeys correlated significantly with Gag-specific, but not Pol- or Env-specific, CD4+and CD8+T lymphocyte responses. These findings demonstrate thatin vitroviral inhibition following vaccination largely reflects Gag-specific cellular immune responses and correlates within vivovirologic control following infection. These data suggest the importance of including Gag in an HIV-1 vaccine in which virologic control is desired.

scholarly journals The Decreased Replicative Capacity of Simian Immunodeficiency Virus SIVmac239Δnef Is Manifest in Cultures of Immature Dendritic Cells and T Cells

2000 ◽  
Vol 74 (5) ◽  
pp. 2406-2413 ◽  
Author(s):  
Davorka Messmer ◽  
Ralf Ignatius ◽  
Christine Santisteban ◽  
Ralph M. Steinman ◽  
Melissa Pope
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Simian Immunodeficiency Virus ◽  
Culture System ◽  
Wild Type ◽  
Virus Dose ◽  
Immunodeficiency Virus

ABSTRACT Transmission of simian immunodeficiency virus SIVmac239Δnef (Δnef) to macaques results in attenuated replication of the virus in most animals and ultimately induces protection against challenge with some pathogenic, wild-type SIV strains. It has been difficult, however, to identify a culture system in which the replication of Δnef is severely reduced relative to that of the wild type. We have utilized a primary culture system consisting of blood-derived dendritic cells (DCs) and autologous T cells. When the DCs were fully differentiated or mature, the DC–CD4+ T-cell mixtures supported replication of both the parental SIV strain, 239 (the wild type), and its mutant withnef deleted (Δnef), irrespective of virus dose and the cell type introducing the virus to the coculture. In contrast, when immature DCs were exposed to Δnef and cocultured with T cells, virus replication was significantly lower than that of the wild type. Activation of the cultures with a superantigen allowed both Δnef and the wild type to replicate comparably in immature DC–T-cell cultures. Immature DCs, which, it has been hypothesized, capture and transmit SIV in vivo, are deficient in supporting replication of Δnef in vitro and may contribute to the reduced pathogenicity of Δnef in vivo.

scholarly journals Early Establishment and Antigen Dependence of Simian Immunodeficiency Virus-Specific CD8+ T-Cell Defects

2007 ◽  
Vol 81 (20) ◽  
pp. 10861-10868 ◽  
Author(s):  
Yvonne M. Mueller ◽  
Constantinos Petrovas ◽  
Duc H. Do ◽  
Susan R. Altork ◽  
Tracy Fischer-Smith ◽  
...  
Keyword(s):  
T Cells ◽  
Simian Immunodeficiency Virus ◽  
Ex Vivo ◽  
Rhesus Macaques ◽  
Viral Escape ◽  
In Vitro Assays ◽  
Effector Memory ◽  
Immunodeficiency Virus ◽  
Induced Apoptosis

ABSTRACT Differentiation and survival defects of human immunodeficiency virus (HIV)-specific CD8+ T cells may contribute to the failure of HIV-specific CD8+ T cells to control HIV replication. It is not known, however, whether simian immunodeficiency virus (SIV)-infected rhesus macaques show comparable defects in these virus-specific CD8+ T cells or when such defects are established during infection. Peripheral blood cells from acutely and chronically infected rhesus macaques were stained ex vivo for memory subpopulations and examined by in vitro assays for apoptosis sensitivity. We show here that SIV-specific CD8+ T cells from chronically SIV infected rhesus macaques show defects comparable to those observed in HIV infection, namely, a skewed CD45RA− CD62L− effector memory phenotype, reduced Bcl-2 levels, and increased levels of spontaneous and CD95-induced apoptosis of SIV-specific CD8+ T cells. Longitudinal studies showed that the survival defects and phenotype are established early in the first few weeks of SIV infection. Most importantly, they appear to be antigen driven, since most probably the loss of epitope recognition due to viral escape results in the reversal of the phenotype and reduced apoptosis sensitivity, something we observed also for animals treated with antiretroviral therapy. These findings further support the use of SIV-infected rhesus macaques to investigate the phenotypic changes and apoptotic defects of HIV-specific CD8+ T cells and indicate that such defects of HIV-specific CD8+ T cells are the result of chronic antigen stimulation.

scholarly journals Rhesus Macaque Resistance to Mucosal Simian Immunodeficiency Virus Infection Is Associated with a Postentry Block in Viral Replication

2002 ◽  
Vol 76 (12) ◽  
pp. 6016-6026 ◽  
Author(s):  
Bo Peng ◽  
Rebecca Voltan ◽  
Lulu Lim ◽  
Yvette Edghill-Smith ◽  
Sanjay Phogat ◽  
...  
Keyword(s):  
T Cells ◽  
Viral Replication ◽  
Rhesus Macaque ◽  
Simian Immunodeficiency Virus ◽  
Reverse Transcription ◽  
Mutation Screening ◽  
Immunodeficiency Virus ◽  
Siv Infection

ABSTRACT Elucidation of the host factors which influence susceptibility to human immunodeficiency virus or simian immunodeficiency virus (SIV) infection and disease progression has important theoretical and practical implications. Rhesus macaque 359, a vaccine control animal, resisted two successive intravaginal challenges with SIVmac251 and failed to seroconvert. Here, after an additional intrarectal SIVmac32H challenge, macaque 359 remained highly resistant to infection. Viral RNA (106 copies/ml) was observed in plasma only at week 2 postchallenge. Virus isolation and proviral DNA were positive only once at week eight postchallenge. The animal remained seronegative and cleared SIV in vivo. Its blood and lymph node cells obtained at 49 weeks after intrarectal challenge did not transmit SIV to a naive macaque. We found that the resistance of macaque 359 to SIV infection was not due to a high level of CD8+ suppressor activity but to an inherent resistance of its CD4+ T cells. To elucidate the basis for the unusually strong resistance of macaque 359 to SIV infection in vivo and in vitro, we investigated early events of viral infection and replication in CD4+ cells of macaque 359, including expression and mutation screening of SIV coreceptors and analysis of viral entry and reverse transcription. Mutation screening revealed no genetic alteration in SIV coreceptors. PCR analysis revealed a significant delay in production of early in vitro reverse transcription intermediates in macaque 359 cells compared to susceptible controls, but cell fusion assays showed that SIV entered the CD4+ CCR5+ cells of macaque 359 as readily as cells of macaques susceptible to SIV infection. Our results suggest that the resistance of macaque 359 to SIV infection is due to a postentry block in viral replication and implicate a cellular inhibitory mechanism in its CD4+ T cells. Identification of this host mechanism will help further elucidate the biochemistry of reverse transcription and may suggest therapeutic strategies. Determining the prevalence of this host resistance mechanism among macaques may lead to better design of SIV pathogenesis and vaccine studies.

scholarly journals Impact of Viral Factors on Very Early In Vivo Replication Profiles in Simian Immunodeficiency Virus SIVagm-Infected African Green Monkeys

2005 ◽  
Vol 79 (10) ◽  
pp. 6249-6259 ◽  
Author(s):  
Ivona Pandrea ◽  
Christopher Kornfeld ◽  
Mickael J.-Y. Ploquin ◽  
Cristian Apetrei ◽  
Abdourahmane Faye ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Primary Infection ◽  
Coreceptor Usage ◽  
Viral Loads ◽  
Immunodeficiency Virus ◽  
The Difference ◽  
Viral Determinants ◽  
Lentiviral Infections ◽  
Green Monkeys

ABSTRACT To better understand which factors govern the levels of viral loads in early lentiviral infections of primates, we developed a model that allows distinguishing between the influences of host and viral factors on viremia. Herein we report that two species of African green monkeys (Chlorocebus sabaeus and C. pygerythrus) infected with their respective wild-type simian immunodeficiency virus SIVagm viruses (SIVagm.sab92018 and SIVagm.ver644) consistently showed reproducible differences in viremia during primary infection but not at later stages of infection. Cross-infections of SIVagm.sab92018 and SIVagm.ver644 into, respectively, C. pygerythrus and C. sabaeus revealed that the dynamics of viral replication during primary infection were dependent on the viral strain used for the infection but not on the host. Hence, the kinetics of SIVagm.sab92018 and SIVagm.ver644 were similar in both sabaeus and vervet animals, indicating that the difference in viremia levels between the two groups during the early phase of infection was not associated with the host. Coreceptor usage for these two strains showed a larger coreceptor repertoire for SIVagm.sab92018, which is able to efficiently use CXCR4 in addition to CCR5, than for SIVagm.ver644, which showed a classical CCR5 coreceptor usage pattern. These differences could not be explained by different charges of the V3 loop for SIVagm.sab92018 and for SIVagm.ver644. In conclusion, our study showed that the extent of virus replication during the primary infection is primarily dependent on viral determinants.

scholarly journals Dysregulation of the Polo-Like Kinase Pathway in CD4+ T Cells Is Characteristic of Pathogenic Simian Immunodeficiency Virus Infection

2004 ◽  
Vol 78 (3) ◽  
pp. 1464-1472 ◽  
Author(s):  
Pavel Bostik ◽  
Geraldine L. Dodd ◽  
Francois Villinger ◽  
Ann E. Mayne ◽  
Aftab A. Ansari
Keyword(s):  
Cell Cycle ◽  
T Cells ◽  
T Cell ◽  
Simian Immunodeficiency Virus ◽  
Intracellular Signaling ◽  
Immunodeficiency Virus ◽  
M Phase ◽  
Siv Infection

ABSTRACT CD4+ T-cell dysfunction highlighted by defects within the intracellular signaling cascade and cell cycle has long been characterized as a direct and/or indirect consequence of human immunodeficiency virus (HIV) infection in humans and simian immunodeficiency virus (SIV) infection in rhesus macaques (RM). Dysregulation of the M phase of the cell cycle is a well-documented effect of HIV or SIV infection both in vivo and in vitro. In this study the effect of SIV infection on the modulation of two important regulators of the M phase—polo-like kinases Plk3 and Plk1—was investigated. We have previously shown that Plk3 is markedly downregulated in CD4+ T cells from SIV-infected disease-susceptible RM but not SIV-infected disease-resistant sooty mangabeys (SM), denoting an association of downregulation with disease progression. Here we show that, in addition to the downregulation, Plk3 exhibits aberrant activation patterns in the CD4+ T cells from SIV-infected RM following T-cell receptor stimulation. Interestingly, in vitro SIV infection of CD4+ T cells leads to the upregulation, rather than downregulation, of Plk3, suggesting that different mechanisms operate in vitro and in vivo. In addition, CD4+ T cells from RM with high viral loads exhibited consistent and significant upregulation of Plk1, concurrent with an aberrant activation-induced Plk1 response, suggesting complex mechanisms of SIV-induced M-phase abnormalities in vivo. Altogether this study presents a novel mechanism underlying M-phase defects observed in CD4+ T cells from HIV or SIV-infected disease-susceptible humans and RM which may contribute to aberrant T-cell responses and disease pathogenesis.

scholarly journals Simian Immunodeficiency Virus Infects Functionally Polarized Memory CD4 T Cells Equivalently In Vivo

2019 ◽  
Vol 93 (9) ◽  
Author(s):  
Stephen H. Lai ◽  
Carly E. Starke ◽  
Jacob K. Flynn ◽  
Carol L. Vinton ◽  
Alexandra M. Ortiz ◽  
...  
Keyword(s):  
T Cells ◽  
Simian Immunodeficiency Virus ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
Lymphoid Tissues ◽  
Disease Pathogenesis ◽  
Tfh Cells ◽  
Immunodeficiency Virus ◽  
Memory Cd4 T Cells

ABSTRACT Among the numerous immunological abnormalities observed in chronically human immunodeficiency virus (HIV)-infected individuals, perturbations in memory CD4 T cells are thought to contribute specifically to disease pathogenesis. Among these, functional imbalances in the frequencies of T regulatory cells (Tregs) and interleukin 17 (IL-17)/IL-22-producing Th cells (Th17/Th22) from mucosal sites and T follicular helper (Tfh) cells in lymph nodes are thought to facilitate specific aspects of disease pathogenesis. However, while preferential infection of Tfh cells is widely thought to create an important viral reservoir in an immunologically privileged site in vivo, whether immunological perturbations among memory CD4 T cell populations are attributable to their relative infectivity by the virus in vivo is unclear. Here we studied peripheral blood and lymphoid tissues from antiretroviral (ARV)-treated and ARV-naive Asian macaques and isolated functionally defined populations of memory CD4 T cells. We then assessed the degree to which these populations were infected by simian immunodeficiency virus (SIV) in vivo, to determine whether particular functionally identified populations of memory CD4 T cells were preferentially infected by the virus. We found that SIV did not preferentially infect Th17 cells, compared to Th1 cells, Th2 cells, or Tregs. Moreover, Th17 cells contributed proportionately to the total pool of infected cells. Taken together, our data suggest that, although Tfh cells are more prone to harbor viral DNA, other functionally polarized cells are equally infected by the virus in vivo and Th17 cells are not preferentially infected. IMPORTANCE Functional perturbations of memory CD4 T cells have been suggested to underlie important aspects of HIV disease progression. However, the mechanisms underlying these perturbations remain unclear. Using a nonhuman primate model of HIV, we show that SIV infects functionally defined populations of memory CD4 T cells equally in different anatomic sites. Thus, preferential infection by the virus is unlikely to cause functional perturbations.

scholarly journals A Rapid Progressor-Specific Variant Clone of Simian Immunodeficiency Virus Replicates Efficiently In Vivo Only in the Absence of Immune Reponses

2007 ◽  
Vol 81 (17) ◽  
pp. 8891-8904 ◽  
Author(s):  
Takeo Kuwata ◽  
Russell Byrum ◽  
Sonya Whitted ◽  
Robert Goeken ◽  
Alicia Buckler-White ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Simian Immunodeficiency Virus ◽  
Immunocompromised Host ◽  
Terminal Phase ◽  
Rapid Progression ◽  
Viral Loads ◽  
Immunodeficiency Virus ◽  
Variant Clone

ABSTRACT A subset of simian immunodeficiency virus (SIV)-infected macaques progresses rapidly to disease with transient SIV-specific immune responses and high viral loads. Unique SIV variants with convergent Env mutations evolve in these rapid progressor (RP) macaques. To address the pathogenic significance of RP-specific variants, we generated infectious molecular clones from the terminal-phase plasma of an RP macaque. Inoculation of macaques with a representative clone, SIVsmH635FC, resulted in a persistent viremia, comparable to that produced by pathogenic SIVsmE543-3, and a chronic disease with progressive loss of CD4+ T cells. However, SIVsmH635FC did not reproduce the rapid-disease phenomenon. Molecular analyses of viruses from these macaques revealed rapid reversion to the wild-type SIVsmE543-3 sequence at two RP-specific sites and slower reversion at another three sites. SIVsmH635FC infection was not sufficient to cause rapid progression even following coinoculation with SIVsmE543-3, despite acute depletion of memory CD4+ T cells. SIVsmH635FC competed efficiently during primary infection in the coinoculated macaques, but SIVsmE543-3 predominated after the development of SIV-specific immune responses. These data suggest that the replication fitness of the RP variant was similar to that of SIVsmE543-3 in a naïve host; however, SIVsmH635FC was at a disadvantage following the development of SIV-specific immune responses. Consistent with these findings, neutralization assays revealed that SIVsmH635FC was highly sensitive to neutralization but that the parental SIVsmE543-3 strain was highly resistant. This study suggests that the evolution of RP-specific variants is the result of replication in a severely immunocompromised host, rather than the direct cause of rapid progression.

scholarly journals Engineered CD4- and CXCR4-Using Simian Immunodeficiency Virus from African Green Monkeys Is Neutralization Sensitive and Replicates in Nonstimulated Lymphocytes

2002 ◽  
Vol 76 (21) ◽  
pp. 10627-10636 ◽  
Author(s):  
Renate R. König ◽  
Egbert Flory ◽  
Stefanie Steidl ◽  
Jeanette Neumann ◽  
Cheick Coulibaly ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Interleukin 2 ◽  
Cell Entry ◽  
V3 Loop ◽  
Coreceptor Usage ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Green Monkeys

ABSTRACT During human immunodeficiency virus type 1 (HIV-1) infection, disease progression correlates with the occurrence of variants using the coreceptor CXCR4 for cell entry. In contrast, apathogenic simian immunodeficiency virus (SIV) from African green monkeys (SIVagm), specifically the molecular virus clone SIVagm3mc, uses CCR5, Bob, and Bonzo as coreceptors throughout the course of infection. The influence of an altered coreceptor usage on SIVagm3mc replication was studied in vitro and in vivo. The putative coreceptor binding domain, the V3 region of the surface envelope (SU) glycoprotein, was replaced by the V3 loop of a CD4- and CXCR4-tropic HIV-1 strain. The resulting virus, termed SIVagm3-X4mc, exclusively used CD4 and CXCR4 for cell entry. Consequently, its in vitro replication was inhibited by SDF-1, the natural ligand of CXCR4. Surprisingly, SIVagm3-X4mc was able to replicate in vitro not only in interleukin-2- and phytohemagglutinin-stimulated but also in nonstimulated peripheral blood mononuclear cells (PBMCs) from nonhuman primates. After experimental infection of two pig-tailed macaques with either SIVagm3-X4mc or SIVagm3mc, the coreceptor usage was maintained during in vivo replication. Cell-associated and plasma viral loads, as well as viral DNA copy numbers, were found to be comparable between SIVagm3mc and SIVagm 3-X4mc infections, and no pathological changes were observed up to 14 months postinfection. Interestingly, the V3 loop exchange rendered SIVagm3-X4mc susceptible to neutralizing antibodies present in the sera of SIVagm3-X4mc- and SIVagm3mc-infected pig-tailed macaques. Our study describes for the first time a successful exchange of a V3 loop in nonpathogenic SIVagm resulting in CD4 and CXCR4 usage and modulation of virus replication in nonstimulated PBMCs as well as sensitivity toward neutralization.

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