scholarly journals Strength of T cell signaling regulates HIV-1 replication and establishment of latency

2018 ◽  
Author(s):  
M Gagne ◽  
D Michaels ◽  
GM Schiralli Lester ◽  
WW Wong ◽  
S Gummuluru ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Signaling ◽  
Latent Reservoir ◽  
Binding Affinities ◽  
Antigen Receptors ◽  
T Cell Signaling ◽  
Chimeric Antigen Receptors ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

AbstractA major barrier to curing HIV is the long-lived latent reservoir that supports re-emergence of HIV upon treatment interruption. Targeting this reservoir will require mechanistic insights into the establishment and maintenance of HIV latency. Whether T cell signaling at the time of HIV-1 infection influences productive replication or latency is not fully understood. We used a panel of chimeric antigen receptors (CARs) with different ligand binding affinities to induce a range of signaling strengths to model differential T cell receptor signaling at the time of HIV-1 infection. Stimulation of T cell lines or primary CD4+ T cells expressing chimeric antigen receptors supported HIV-1 infection regardless of affinity for ligand; however, only signaling by the highest affinity receptor facilitated HIV-1 expression. Activation of chimeric antigen receptors that had intermediate and low binding affinities did not support provirus transcription, suggesting that a minimal signal is required for optimal HIV-1 expression. In addition, strong signaling at the time of infection produced a latent population that was readily inducible, whereas latent cells generated in response to weaker signals were not easily reversed. Chromatin immunoprecipitation showed HIV-1 transcription was limited by transcriptional elongation and that robust signaling decreased the presence of negative elongation factor, a pausing factor, by more than 80%. These studies demonstrate that T cell signaling influences HIV-1 infection and the establishment of different subsets of latently infected cells, which may have implications for targeting the HIV reservoir.Author SummaryActivation of CD4+ T cells facilitates HIV-1 infection; however, whether there are minimal signals required for the establishment of infection, replication, and latency has not been explored. To determine how T cell signaling influences HIV-1 infection and the generation of latently infected cells, we used chimeric antigen receptors to create a tunable model. Stronger signals result in robust HIV-1 expression and an inducible latent population. Minimal signals predispose cells towards latent infections that are refractory to reversal. We discovered that repression of HIV-1 transcription immediately after infection is due to RNA polymerase II pausing and inefficient transcription elongation. These studies demonstrate that signaling events influence the course of HIV-1 infection and have implications for cure strategies. They also provide a mechanistic explanation for why a significant portion of the HIV latent reservoir is not responsive to latency reversing agents which function by modifiying chromatin.

scholarly journals ADAP1 promotes latent HIV-1 reactivation by selectively tuning a T cell signaling-transcriptional axis

2021 ◽  
Author(s):  
Nora Guadalupe Ramirez ◽  
Jeon Lee ◽  
Yue Zheng ◽  
Lianbo Li ◽  
Bryce Dennis ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Signaling ◽  
Ph Domain ◽  
T Cell Signaling ◽  
Cellular Assays ◽  
Biological Responses ◽  
T Cell Stimulation ◽  
Infected Cells ◽  
Latent Hiv ◽  
Hiv 1

Immune stimulation fuels cell signaling transcriptional programs inducing biological responses to eliminate virus infected cells. Yet, retroviruses that integrate into host cell chromatin, such as HIV1, coopt these programs to switch between latent and reactivated states; however, the regulatory mechanisms are still unfolding. Here, we implemented a functional screen leveraging HIV1 dependence on CD4+ T cell signaling transcriptional programs and discovered ADAP1 is an undescribed modulator of HIV1 proviral fate. Specifically, we report ADAP1 (ArfGAP with dual PH domain containing protein 1), a previously thought neuronal restricted factor, is an amplifier of select T cell signaling programs. Using complementary biochemical and cellular assays, we demonstrate ADAP1 inducibly interacts with the immune signalosome to directly stimulate KRAS GTPase activity thereby augmenting T cell signaling through targeted activation of the ERK/AP1 axis. Single cell transcriptomics analysis revealed loss of ADAP1 function blunts gene programs upon T cell stimulation consequently dampening latent HIV1 reactivation. Our combined experimental approach defines ADAP1 as an unexpected tuner of T cell programs coopted by HIV1 for latency escape.

scholarly journals Antigen responsive CD4+ T cell clones contribute to the HIV-1 latent reservoir

2020 ◽  
Author(s):  
Pilar Mendoza ◽  
Julia R. Jackson ◽  
Thiago Oliveira ◽  
Christian Gaebler ◽  
Victor Ramos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Half Life ◽  
Latent Reservoir ◽  
Small Subset ◽  
T Cell Clones ◽  
Cell Clones ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

AbstractAntiretroviral therapy suppresses but does not cure HIV-1 infection due to the existence of a long-lived reservoir of latently infected cells. The reservoir has an estimated half-life of 44 months and is largely composed of clones of infected CD4+ T cells. The long half-life appears to result in part from expansion and contraction of infected CD4+ T cell clones. However, the mechanisms that govern this process are poorly understood. To determine whether the clones might result from, and be maintained by exposure to antigen, we measured responses of reservoir cells to a small subset of antigens from viruses that produce chronic or recurrent infections. Despite the limited panel of test antigens, clones of antigen responsive CD4+ T cells containing defective or intact latent proviruses were found in 7 out of 8 individuals studied. Thus, chronic or repeated exposure to antigen may contribute to the longevity of the HIV-1 reservoir by stimulating the clonal expansion of latently infected CD4+ T cells.

scholarly journals Expanded cellular clones carrying replication-competent HIV-1 persist, wax, and wane

2018 ◽  
Vol 115 (11) ◽  
pp. E2575-E2584 ◽  
Author(s):  
Zheng Wang ◽  
Evelyn E. Gurule ◽  
Timothy P. Brennan ◽  
Jeffrey M. Gerold ◽  
Kyungyoon J. Kwon ◽  
...  
Keyword(s):  
T Cell ◽  
Cellular Proliferation ◽  
Integration Site ◽  
Virus Production ◽  
Viral Reactivation ◽  
Latent Reservoir ◽  
Major Barrier ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

The latent reservoir for HIV-1 in resting CD4+ T cells is a major barrier to cure. Several lines of evidence suggest that the latent reservoir is maintained through cellular proliferation. Analysis of this proliferative process is complicated by the fact that most infected cells carry defective proviruses. Additional complications are that stimuli that drive T cell proliferation can also induce virus production from latently infected cells and productively infected cells have a short in vivo half-life. In this ex vivo study, we show that latently infected cells containing replication-competent HIV-1 can proliferate in response to T cell receptor agonists or cytokines that are known to induce homeostatic proliferation and that this can occur without virus production. Some cells that have proliferated in response to these stimuli can survive for 7 d while retaining the ability to produce virus. This finding supports the hypothesis that both antigen-driven and cytokine-induced proliferation may contribute to the stability of the latent reservoir. Sequencing of replication-competent proviruses isolated from patients at different time points confirmed the presence of expanded clones and demonstrated that while some clones harboring replication-competent virus persist longitudinally on a scale of years, others wax and wane. A similar pattern is observed in longitudinal sampling of residual viremia in patients. The observed patterns are not consistent with a continuous, cell-autonomous, proliferative process related to the HIV-1 integration site. The fact that the latent reservoir can be maintained, in part, by cellular proliferation without viral reactivation poses challenges to cure.

scholarly journals Synergistic T cell signaling by 41BB and CD28 is optimally achieved by membrane proximal positioning within parallel chimeric antigen receptors

2021 ◽  
Vol 2 (12) ◽  
pp. 100457
Author(s):  
Tamara Muliaditan ◽  
Leena Halim ◽  
Lynsey M. Whilding ◽  
Benjamin Draper ◽  
Daniela Y. Achkova ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Signaling ◽  
Antigen Receptors ◽  
T Cell Signaling ◽  
Chimeric Antigen Receptors

scholarly journals Similar frequency and inducibility of intact HIV-1 proviruses in blood and lymph nodes

2020 ◽  
Author(s):  
Alyssa R Martin ◽  
Alexandra M Bender ◽  
Jada Hackman ◽  
Kyungyoon J Kwon ◽  
Briana A Lynch ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Nodes ◽  
Cd4 T Cells ◽  
Viral Rna ◽  
Latent Reservoir ◽  
Similar Frequency ◽  
Latently Infected ◽  
Infected Cells ◽  
Secondary Lymphoid Organs ◽  
Hiv 1

Abstract Background The HIV-1 latent reservoir (LR) in resting CD4 + T cells is a barrier to cure. LR measurements are commonly performed on blood samples and therefore may miss latently infected cells residing in tissues, including lymph nodes. Methods We determined the frequency of intact HIV-1 proviruses and proviral inducibility in matched peripheral blood (PB) and lymph node (LN) samples from ten HIV-1-infected patients on ART using the intact proviral DNA assay and a novel quantitative viral induction assay. Prominent viral sequences from induced viral RNA were characterized using a next-generation sequencing assay. Results The frequencies of CD4 + T cells with intact proviruses were not significantly different in PB vs LN (61vs104/10 6CD4 + cells), and were substantially lower than frequencies of CD4 + T cells with defective proviruses. The frequencies of CD4 + T cells induced to produce high levels of viral RNA were not significantly different in PB vs LN (4.3/10 6 vs 7.9/10 6), but were 14-fold lower than the frequencies of cells with intact proviruses. Sequencing of HIV-1 RNA from induced proviruses revealed comparable sequences in paired PB and LN samples. Conclusions These results further support the use of PB as an appropriate proxy for the HIV-1 LR in secondary lymphoid organs

scholarly journals Reactivation Kinetics of HIV-1 and Susceptibility of Reactivated Latently Infected CD4+T Cells to HIV-1-Specific CD8+T Cells

2015 ◽  
Vol 89 (18) ◽  
pp. 9631-9638 ◽  
Author(s):  
Victoria E. K. Walker-Sperling ◽  
Valerie J. Cohen ◽  
Patrick M. Tarwater ◽  
Joel N. Blankson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Time Frame ◽  
Virus Release ◽  
Latently Infected ◽  
Shock And Kill ◽  
Infected Cells ◽  
Kinetics Of ◽  
Hiv 1

ABSTRACTThe “shock and kill” model of human immunodeficiency virus type 1 (HIV-1) eradication involves the induction of transcription of HIV-1 genes in latently infected CD4+T cells, followed by the elimination of these infected CD4+T cells by CD8+T cells or other effector cells. CD8+T cells may also be needed to control the spread of new infection if residual infected cells are present at the time combination antiretroviral therapy (cART) is discontinued. In order to determine the time frame needed for CD8+T cells to effectively prevent the spread of HIV-1 infection, we examined the kinetics of HIV transcription and virus release in latently infected cells reactivatedex vivo. Isolated resting, primary CD4+T cells from HIV-positive (HIV+) subjects on suppressive regimens were found to upregulate cell-associated HIV-1 mRNA within 1 h of stimulation and produce extracellular virus as early as 6 h poststimulation. In spite of the rapid kinetics of virus production, we show that CD8+T cells from 2 out of 4 viremic controllers were capable of effectively eliminating reactivated autologous CD4+cells that upregulate cell-associated HIV-1 mRNA. The results have implications for devising strategies to prevent rebound viremia due to reactivation of rare latently infected cells that persist after potentially curative therapy.IMPORTANCEA prominent HIV-1 cure strategy termed “shock and kill” involves the induction of HIV-1 transcription in latently infected CD4+T cells with the goal of elimination of these cells by either the cytotoxic T lymphocyte response or other immune cell subsets. However, the cytotoxic T cell response may also be required after curative treatment if residual latently infected cells remain. The kinetics of HIV-1 reactivation indicate rapid upregulation of cell-associated HIV-1 mRNA and a 5-h window between transcription and virus release. Thus, HIV-specific CD8+T cell responses likely have a very short time frame to eliminate residual latently infected CD4+T cells that become reactivated after discontinuation of antiretroviral therapy following potentially curative treatment strategies.

scholarly journals BTLA and PD-1 employ distinct phosphatases to differentially repress T cell signaling

2019 ◽  
Author(s):  
Xiaozheng Xu ◽  
Amitkumar Fulzele ◽  
Yunlong Zhao ◽  
Zijun Wu ◽  
Yanyan Hu ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Signaling ◽  
Cell Activity ◽  
Immune Checkpoints ◽  
Clinical Activity ◽  
T Cell Signaling ◽  
Tcr Signaling ◽  
Durable Response ◽  
Infected Cells ◽  
Cell Death Protein

ABSTRACTT cell-mediated destruction of tumors and virus-infected cells is restricted by co-inhibitory receptors such as programmed cell death protein 1 (PD-1). Monoclonal antibodies blocking PD-1 have produced impressive clinical activity against human cancers, but durable response is limited to a minority of patients. Previous results suggest that B and T lymphocyte attenuator (BTLA), a co-inhibitory receptor structurally related to PD-1, may contribute to the resistance to PD-1 targeted therapy and co-blockade of BTLA can enhance the efficacy of anti-PD-1 immunotherapy. However, the biochemical mechanism by which BTLA represses T cell activity and to what extent the mechanism differs from that of PD-1 is unknown. Here we examine differences in the ability of BTLA and PD-1 to recruit effector molecules and regulate T cell signaling. We show that PD-1 and BTLA recruit different tyrosine phosphatases to regulate either CD28 or T cell antigen receptor (TCR)-signaling cascades. Our data reveal unexpected disparities between two structurally related immune checkpoints and two phosphatase paralogs.

scholarly journals Quantifying the turnover of transcriptional subclasses of HIV-1-infected cells

2013 ◽  
Author(s):  
Christian L Althaus ◽  
Beda Joos ◽  
Alan S Perelson ◽  
Huldrych F Günthard
Keyword(s):  
Peripheral Blood ◽  
Chronic Infection ◽  
Burst Size ◽  
Acute Infection ◽  
The Body ◽  
Latent Reservoir ◽  
Published Data ◽  
Latently Infected ◽  
Infected Cells ◽  
Hiv 1

Background: HIV-1-infected cells in peripheral blood can be grouped into different transcriptional subclasses. Quantifying the turnover of these cellular subclasses can provide important insights into the viral life cycle and the generation and maintenance of latently infected cells. Results: We used previously published data from five patients chronically infected with HIV-1 that initiated combination antiretroviral therapy (cART). Patient-matched PCR for unspliced and multiply spliced viral RNAs combined with limiting dilution analysis provided measurements of transcriptional profiles at the single cell level. Furthermore, measurement of intracellular transcripts and extracellular virion-enclosed HIV-1 RNA allowed us to distinguish productive from non-productive cells. We developed a mathematical model describing the dynamics of plasma virus and the transcriptional subclasses of HIV-1-infected cells. Fitting the model to the data allowed us to better understand the phenotype of different transcriptional subclasses and their contribution to the overall turnover of HIV-1 before and during cART. The average number of virus-producing cells in peripheral blood is small during chronic infection (25.7 cells per ml). We find that 14.0%, 0.3% and 21.2% of infected cells become defectively, latently and persistently infected cells, respectively. Assuming that the infection is homogenous throughout the body, we estimate an average in vivo viral burst size of 2.1 x 10^4 virions per cell. Conclusions: Our study provides novel quantitative insights into the turnover and development of different subclasses of HIV-1-infected cells. The model predicts that the pool of latently infected cells becomes rapidly established during the first months of acute infection and continues to increase slowly during the first years of chronic infection. Having a detailed understanding of this process will be useful for the evaluation of viral eradication strategies that aim to deplete the latent reservoir of HIV-1.

scholarly journals Antigen-responsive CD4+ T cell clones contribute to the HIV-1 latent reservoir

2020 ◽  
Vol 217 (7) ◽  
Author(s):  
Pilar Mendoza ◽  
Julia R. Jackson ◽  
Thiago Y. Oliveira ◽  
Christian Gaebler ◽  
Victor Ramos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Half Life ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Latent Reservoir ◽  
T Cell Clones ◽  
Cell Clones ◽  
Latently Infected ◽  
Hiv 1

Antiretroviral therapy suppresses but does not cure HIV-1 infection due to the existence of a long-lived reservoir of latently infected cells. The reservoir has an estimated half-life of 44 mo and is largely composed of clones of infected CD4+ T cells. The long half-life appears to result in part from expansion and contraction of infected CD4+ T cell clones. However, the mechanisms that govern this process are poorly understood. To determine whether the clones might result from and be maintained by exposure to antigen, we measured responses of reservoir cells to a small subset of antigens from viruses that produce chronic or recurrent infections. Despite the limited panel of test antigens, clones of antigen-responsive CD4+ T cells containing defective or intact latent proviruses were found in seven of eight individuals studied. Thus, chronic or repeated exposure to antigen may contribute to the longevity of the HIV-1 reservoir by stimulating the clonal expansion of latently infected CD4+ T cells.

scholarly journals Humanized Mouse Model of HIV-1 Latency with Enrichment of Latent Virus in PD-1+and TIGIT+CD4 T Cells

2019 ◽  
Vol 93 (10) ◽  
Author(s):  
George N. Llewellyn ◽  
Eduardo Seclén ◽  
Stephen Wietgrefe ◽  
Siyu Liu ◽  
Morgan Chateau ◽  
...  
Keyword(s):  
T Cells ◽  
Mouse Model ◽  
Ex Vivo ◽  
Latent Reservoir ◽  
Humanized Mouse ◽  
Humanized Mouse Model ◽  
Latently Infected ◽  
Infected Cells ◽  
Latent Hiv ◽  
Hiv 1

ABSTRACTCombination anti-retroviral drug therapy (ART) potently suppresses HIV-1 replication but does not result in virus eradication or a cure. A major contributing factor is the long-term persistence of a reservoir of latently infected cells. To study this reservoir, we established a humanized mouse model of HIV-1 infection and ART suppression based on an oral ART regimen. Similar to humans, HIV-1 levels in the blood of ART-treated animals were frequently suppressed below the limits of detection. However, the limited timeframe of the mouse model and the small volume of available samples makes it a challenging model with which to achieve full viral suppression and to investigate the latent reservoir. We therefore used anex vivolatency reactivation assay that allows a semiquantitative measure of the latent reservoir that establishes in individual animals, regardless of whether they are treated with ART. Using this assay, we found that latently infected human CD4 T cells can be readily detected in mouse lymphoid tissues and that latent HIV-1 was enriched in populations expressing markers of T cell exhaustion, PD-1 and TIGIT. In addition, we were able to use theex vivolatency reactivation assay to demonstrate that HIV-specific TALENs can reduce the fraction of reactivatable virus in the latently infected cell population that establishesin vivo, supporting the use of targeted nuclease-based approaches for an HIV-1 cure.IMPORTANCEHIV-1 can establish latent infections that are not cleared by current antiretroviral drugs or the body’s immune responses and therefore represent a major barrier to curing HIV-infected individuals. However, the lack of expression of viral antigens on latently infected cells makes them difficult to identify or study. Here, we describe a humanized mouse model that can be used to detect latent but reactivatable HIV-1 in both untreated mice and those on ART and therefore provides a simple system with which to study the latent HIV-1 reservoir and the impact of interventions aimed at reducing it.

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