Maintenance of Functional CD57+ Cytolytic CD4+ T Cells in HIV+ Elite Controllers.
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ABSTRACT:
SUBMITTER: Phetsouphanh C
PROVIDER: S-EPMC6694780 | biostudies-literature | 2019
REPOSITORIES: biostudies-literature
Publications
Maintenance of Functional CD57+ Cytolytic CD4+ T Cells in HIV+ Elite Controllers.
Phetsouphanh Chansavath C Aldridge Daniel D Marchi Emanuele E Munier C Mee Ling CML Meyerowitz Jodi J Murray Lyle L Van Vuuren Cloete C Goedhals Dominique D Fidler Sarah S Kelleher Anthony A Klenerman Paul P Frater John J
Frontiers in immunology 20190808
Cytolytic CD4+ T cells play a prominent role in chronic viral infection. CD4+ CTLs clones specific for HIV-1 Nef and Gag are capable of killing HIV-1 infected CD4+ T cells and macrophages. Additionally, HIV-specific cytolytic CD4+ T cell responses in acute HIV infection are predictive of disease progression. CD57 expression on CD4s identifies cytolytic cells. These cells were dramatically increased in chronic HIV infection. CD57 expression correlated with cytolytic granules, granzyme B and perfo ...[more]
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Project description:Human immunodeficiency virus (HIV)-specific B-cell responses in infected individuals are maintained by active HIV replication. Suppression of viremia by antiretroviral therapy (ART) leads to quantitative and qualitative changes that remain unclear. Accordingly, B-cell responses were investigated in elite controllers (ECs), who maintain undetectable HIV levels without ART, and in individuals whose viremia was suppressed by ART. Despite a higher HIV burden in the ART group, compared with the EC group, frequencies of HIV-specific B cells were higher in the EC group, compared with those in the ART group. However, the initiation of ART in several ECs was associated with reduced frequencies of HIV-specific B cells, suggesting that responses are at least in part sustained by HIV replication. Furthermore, B-cell responses to tetanus toxin but not influenza hemagglutinin in the ART group were lower than those in the EC group. Thus, the superior HIV-specific humoral response in ECs versus ART-treated individuals is likely due to a more intact humoral immune response in ECs and/or distinct responses to residual HIV replication.
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Project description:We previously demonstrated in the Chinese macaque model that an oral vaccine made of inactivated SIV and Lactobacillus plantarum induced CD8(+) regulatory T-cells, which suppressed the activation of SIV(+)CD4(+) T-cells, prevented SIV replication, and protected macaques from SIV challenges. Here, we sought whether a similar population of CD8(+) T-regs would induce the suppression of HIV replication in elite controllers (ECs), a small population (3‰) of HIV-infected patients with undetectable HIV replication. For that purpose, we investigated the in vitro antiviral activity of fresh CD8(+) T-cells on HIV-infected CD4(+) T-cells taken from 10 ECs. The 10 ECs had a classical genomic profile: all of them carried the KIR3DL1 gene and 9 carried at least 1 allele of HLA-B:Bw4-80Ile (i.e., with an isoleucine residue at position 80). In the nine HLA-B:Bw4-80Ile-positive patients, we demonstrated a strong viral suppression by KIR3DL1-expressing CD8(+) T-cells that required cell-to-cell contact to switch off the activation signals in infected CD4(+) T-cells. KIR3DL1-expressing CD8(+) T-cells withdrawal and KIR3DL1 neutralization by a specific anti-killer cell immunoglobulin-like receptor (KIR) antibody inhibited the suppression of viral replication. Our findings provide the first evidence for an instrumental role of KIR-expressing CD8(+) regulatory T-cells in the natural control of HIV-1 infection.
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Project description:Antiretroviral therapy (ART) has the potency of suppressing systemic viral replication and spread. Still, persistent human immunodeficiency virus type-1 (HIV) survive for decades during treatment in latently infected cells, making up the latent viral reservoir. This reservoir is believed to reside in subtypes of memory T cells and cell from monocytic lineages, but some functional and naïve T cells have also shown to carry latent HIV. Eradication of latently infected cells, in terms of a sterilizing cure, have proven to be a hurdle since there is a heterogeneity in mechanisms governing latency and integration site into the genome. Over the course of suppressive therapy, persisting HIV, sustained by low levels of viral replication, homeostatic proliferation, and cell to cell transmission, is a driver of chronic immune activation in the body. For the immune system to elicit an appropriate inflammatory response it is dependent on secretion of inflammatory molecules, such as chemokines and cytokines. Most chemokines are pro-inflammatory factors that facilitate leukocyte recruitment to site of inflammation where they can exert their regulatory role in response to pathological and physiological stressors e.g., infection, inflammation, and tissue damage. Alterations in chemokine receptor expression and chemokine levels modulates the activity of the immune response and in HIV infection contribute to chronic inflammation and mortality. Therefore, people living with HIV on suppressive therapy (PLWH) are at higher risk of age associated co-morbidities due to elevated immune activation and chronic inflammation induced by ART toxicities, microbiome dysbiosis leading to microbial translocation and dysregulated immune cell activation and function. As a result, the causative HIV pathogenesis and immune dysfunction further chronic immune activation. This result in a vicious cycle as immune activation is driver of HIV disease progression and inflammaeging leading to earlier onset of age-related diseases. An alternative approach in cure strategies is a functional cure for HIV aiming at suppressing viral replication without ART. A model for functional cure studies are elite controllers (EC). EC constitute a small fraction of HIV+ individuals (<0.5%) exhibiting the unique characteristic of natural control of viral replication in absence of ART. However, there is a population-based heterogeneity of how these individuals naturally supress viral replication. This heterogeneity is caused by viral genetic factors, variability of integration site in the human genome, together with host response against the pathogen and immunological factors. In terms of immune cell activation, studies have shown how EC maintain lower levels of inflammatory markers compared to PLWH. Contradictory, some studies have shown elevated inflammatory markers in EC which could be attributed to the heterogeneity of the EC group or as others have shown it is a consequence of loss of spontaneous control of HIV. Therefore, as no consensus exist further studies comparing variability of immune function between EC and ART can aid in understanding the mechanisms of natural control of HIV. In our recent study (Sperk et al 2021, iScience) we hypothesised that modulated CCR6/CCL20 chemokine axis and CCR2-CCL7-CCL2 signalling can play a protective role in the EC phenotype. Downregulation of CCR2 and CCR6 receptors in lymphocytes and higher plasma abundance of CCL4, CCL7 and CCL20 in EC compared to the HIV-negative controls can provide natural resistance to HIV-infection. In the present study, we further extended our analysis to evaluate the expression profile dynamics of key chemokine receptors, CCR2, CCR3, CCR5 and CCR6, in successfully treated PLWH. We compared well treated PLWH with HIV-1 elite controllers and its association with HIV-1 persistence. Furthermore, cell populations of interest were isolated for liquid chromatography mass spectrometry (LC-MS/MS) based untargeted proteomics analysis to evaluate specific characteristics regulating these cell populations and their role in HIV persistence. Our study provides important understanding of the chemokine receptor dynamics and its role in HIV persistence that differentiate elite controllers from long term treated PLWH.
2022-04-22 | PXD027749 | Pride
Project description:BackgroundData on HIV-1 controllers in Africa are scarce. We report the proportion of HIV-1 controllers in a group of adults prospectively monitored with frequent viral load measurements as part of a clinical trial in West Africa.MethodsFor the Temprano trial, antiretroviral therapy (ART)-naive HIV-1 infected adults with no criteria for starting ART were randomized to start ART immediately or defer ART until the WHO starting criteria were met. Plasma viral load was measured every 6 months. The trial follow-up was 30 months. We considered all Temprano participants randomized to defer ART. Patients with all semestrial viral <2000 copies/ml and still off ART at month 30 were defined as HIV-1 controllers. Controllers with all viral loads <50 copies/ml were defined as elite controllers, the rest as viremic controllers.ResultsOf the 1023 HIV-1-infected adults randomized in the Temprano deferred-ART group, 18 (1.8%) met the criteria for classification as HIV controllers, of whom seven (0.7%) were elite controllers and 11 (1.1%) viremic controllers. The HIV-1 controllers had low peripheral blood mononuclear cell HIV-1 DNA and low inflammatory marker levels. They maintained high CD4+ cell count and percentages and had a low morbidity rate.DiscussionHIV controllers exist in Africa at a proportion close to that reported elsewhere. They represent a small fraction of all HIV-1-infected patients but raise important questions. Further studies should assess whether starting ART might represent more risk than benefit for some controllers, and where it does, how to identify these patients before they start ART.
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