Effects of HCV co-infection on apoptosis of CD4+ T-cells in HIV-positive patients

Apoptosis importantly contributes to loss of CD4+ T-cells in HIV infection, and modification of their apoptosis may explain why HIV/HCV (hepatitis C virus)-co-infected patients are more likely to die from liver-related causes, although the effects of HCV on HIV infection remain unclear. In the present study, we studied in a cross-sectional and serial analysis spontaneous ex vivo CD4+ T-cell apoptosis in HIV/HCV-co-infected and HIV-mono-infected patients before and after HAART (highly active antiretroviral therapy). Apoptosis of peripheral blood CD4+ T-cells was measured by both a PARP [poly(ADP-ribose) polymerase] and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling) assay to detect cells with irreversible apoptosis. Although hepatitis C alone did not increase CD4+ T-cell apoptosis, HCV co-infection disproportionately increased elevated rates of apoptosis in CD4+ T-cells from untreated HIV-positive patients. Increased CD4+ T-cell apoptosis was closely correlated with HIV, but not HCV, viral loads. Under HAART, increased rates of CD4+ T-cell apoptosis rapidly decreased both in HIV-mono-infected and HIV/HCV-co-infected patients, without any significant difference in apoptosis rates between the two patient groups after 4 weeks of therapy. Nevertheless residual CD4+ T-cell apoptosis did not reach the normal levels seen in healthy controls and remained higher in HIV patients receiving protease inhibitors than in patients with other antiretroviral regimens. The results of the present study suggest that HCV co-infection sensitizes CD4+ T-cells towards apoptosis in untreated HIV-positive patients. However, this effect is rapidly lost under effective antiretroviral therapy.

Download Full-text

Telomere and ATM Dynamics in CD4 T-Cell Depletion in Active and Virus-Suppressed HIV Infections

Journal of Virology ◽

10.1128/jvi.01061-20 ◽

2020 ◽

Vol 94 (22) ◽

Author(s):

Sushant Khanal ◽

Qiyuan Tang ◽

Dechao Cao ◽

Juan Zhao ◽

Lam Nhat Nguyen ◽

...

Keyword(s):

Dna Damage ◽

T Cells ◽

T Cell ◽

Hiv Infection ◽

Cell Apoptosis ◽

Cd4 T Cells ◽

Molecular Mechanisms ◽

Cd4 T Cell ◽

Cell Aging

ABSTRACT CD4 T-cell depletion is a hallmark of HIV/AIDS, but the underlying mechanism is still unclear. We have recently shown that ataxia-telangiectasia-mutated (ATM) deficiency in CD4 T cells accelerates DNA damage, telomere erosion, and cell apoptosis in HIV-infected individuals on antiretroviral therapy (ART). Whether these alterations in ART-treated HIV subjects occur in vitro in HIV-infected CD4 T cells remains unknown. In this study, we employed a cellular model of HIV infection to characterize the mechanisms underlying CD4 T-cell destruction by analyzing the telomeric DNA damage response (DDR) and cellular apoptosis in highly permissive SupT1 cells, followed by the validation of our observations in primary CD4 T cells with active or drug-suppressed HIV infection. Specifically, we established an in vitro HIV T-cell culture system with viral replication and raltegravir (RAL; an integrase inhibitor) suppression, mimicking active and ART-controlled HIV infection in vivo. We demonstrated that HIV-induced, telomeric DDR plays a pivotal role in triggering telomere erosion, premature T-cell aging, and CD4 T-cell apoptosis or depletion via dysregulation of the PI3K/ATM pathways. This in vitro model provides a new tool to investigate HIV pathogenesis, and our results shed new light on the molecular mechanisms of telomeric DDR and CD4 T-cell homeostasis during HIV infection. IMPORTANCE The hallmark of HIV infection is a gradual depletion of CD4 T cells, with a progressive decline of host immunity. How CD4 T cells are depleted in individuals with active and virus-suppressed HIV infection remains unclear. In this study, we employed a cellular model of HIV infection to characterize the mechanisms underlying CD4 T-cell destruction by analyzing the chromosome end (telomere) DNA damage response (DDR) and cellular apoptosis in a T-cell line (highly permissive SupT1 cells), as well as in primary CD4 T cells with active or drug-suppressed HIV infection. We demonstrated that HIV-induced telomeric DDR plays a critical role in inducing telomere loss, premature cell aging, and CD4 T-cell apoptosis or depletion via dysregulation of the PI3K/ATM pathways. This study sheds new light on the molecular mechanisms of telomeric DDR and its role in CD4 T-cell homeostasis during HIV infection.

Download Full-text

The ARTμS: a novel microfluidic CD4+ T-cell enumeration system for monitoring antiretroviral therapy in HIV patients

Lab on a Chip ◽

10.1039/c5lc01153a ◽

2016 ◽

Vol 16 (3) ◽

pp. 506-514 ◽

Cited By ~ 9

Author(s):

Qian Liu ◽

Alexis Chernish ◽

Jacquelyn A. DuVall ◽

Yiwen Ouyang ◽

Jingyi Li ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Antiretroviral Therapy ◽

Microfluidic Device ◽

Dna Content ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

Hiv Patients ◽

Cell Enumeration

An integrated microfluidic device that enumerates CD4+ T-cells based on DNA content.

Download Full-text

Modulation of LPS-Induced CD4+ T-Cell Activation and Apoptosis by Antioxidants in Untreated Asymptomatic HIV Infected Participants: AnIn VitroStudy

Clinical and Developmental Immunology ◽

10.1155/2013/631063 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 8

Author(s):

S. Mburu ◽

J. L. Marnewick ◽

A. Abayomi ◽

H. Ipp

Keyword(s):

T Cells ◽

T Cell ◽

Vitamin C ◽

T Cell Activation ◽

Cd4 T Cells ◽

Cell Activation ◽

Annexin V ◽

Cd4 T Cell ◽

Hiv Positive ◽

Cd25 Expression

Persistent immune activation characterises HIV infection and is associated with depletion of CD4+ T-cells and increased risk of disease progression. Early loss of gut mucosal integrity results in the translocation of microbial products such as lipopolysaccharide (LPS) into the systemic circulation. This is an important source of on-going immune stimulation. The purpose of this study was to determine levels of CD4+ T-cell activation (%CD25 expression) and apoptosis (% annexin V/7-AAD) in asymptomatic, untreated HIV infection at baseline and after stimulation with LPS and incubation with or without vitamin C and N-acetylcysteine. LPS induced a significant (P<0.03) increase in %CD25 expression, annexin V, and 7-AAD in HIV positive individuals. NAC in combination with vitamin C, significantly (P=0.0018) reduced activation and early apoptosis of CD4+ T-cells to a greater degree than with either antioxidant alone. Certain combinations of antioxidants could be important in reducing the harmful effects of chronic immune activation and thereby limit CD4+ T-cell depletion. Importantly, we showed that CD4+ T-cells of the HIV positive group responded better to a combination of the antioxidants at this stage than those of the controls. Therefore, appropriate intervention at this asymptomatic stage could rescue the cells before repetitive activation results in the death of CD4+ T-cells.

Download Full-text

Increased apoptosis of peripheral blood T cells following allogeneic hematopoietic cell transplantation

Blood ◽

10.1182/blood.v95.12.3832.012k32_3832_3839 ◽

2000 ◽

Vol 95 (12) ◽

pp. 3832-3839 ◽

Cited By ~ 3

Author(s):

Ming-Tseh Lin ◽

Li-Hui Tseng ◽

Haydar Frangoul ◽

Ted Gooley ◽

Ji Pei ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Transplantation ◽

Cell Apoptosis ◽

Hematopoietic Cell Transplantation ◽

Hematopoietic Cell ◽

Allogeneic Hematopoietic Cell Transplantation ◽

Cd4 T Cell ◽

Spontaneous Apoptosis ◽

T Cell Apoptosis

Lymphopenia and immune deficiency are significant problems following allogeneic hematopoietic cell transplantation (HCT). It is largely assumed that delayed immune reconstruction is due to a profound decrease in thymus-dependent lymphopoiesis, especially in older patients, but apoptosis is also known to play a significant role in lymphocyte homeostasis. Peripheral T cells from patients who received HCT were studied for evidence of increased cell death. Spontaneous apoptosis was measured in CD3+ T cells following a 24-hour incubation using 7-amino-actinomycin D in conjunction with the dual staining of cell surface antigens. Apoptosis was significantly greater among CD3+ T cells taken from patients 19-23 days after transplantation (30.4% ± 12.5%,P < .05), and 1 year after transplantation (9.7% ± 2.8%, P < .05) compared with healthy controls (4.0% ± 1.5%). Increased apoptosis occurred preferentially in HLA (human leukocyte antigen)-DR positive cells and in both CD3+/CD4+ and CD3+/CD8+ T-cell subsets, while CD56+/CD3− natural killer cells were relatively resistant to apoptosis. The extent of CD4+T-cell apoptosis was greater in patients with grade II-IV acute graft-versus-host disease (GVHD) (33.9% ± 11.3%) compared with grade 0-I GVHD (14.6 ± 6.5%, P < .05). T-cell apoptosis was also greater in patients who received transplantations from HLA-mismatched donors (39.5% ± 10.4%,P < .05) or HLA-matched unrelated donors (32.1% ± 11.4%, P < .05) compared with patients who received transplantations from HLA-identical siblings (19.6% ± 6.7%). The intensity of apoptosis among CD4+ T cells was significantly correlated with a lower CD4+ T-cell count. Together, these observations suggest that activation of T cells in vivo, presumably by alloantigens, predisposes the cells to spontaneous apoptosis, and this phenomenon is associated with lymphopenia. Activation-induced T-cell apoptosis may contribute to delayed immune reconstitution following HCT.

Download Full-text

Broadly directed virus-specific CD4+ T cell responses are primed during acute hepatitis C infection, but rapidly disappear from human blood with viral persistence

Journal of Experimental Medicine ◽

10.1084/jem.20100388 ◽

2012 ◽

Vol 209 (1) ◽

pp. 61-75 ◽

Cited By ~ 142

Author(s):

Julian Schulze zur Wiesch ◽

Donatella Ciuffreda ◽

Lia Lewis-Ximenez ◽

Victoria Kasprowicz ◽

Brian E. Nolan ◽

...

Keyword(s):

T Cells ◽

Hepatitis C ◽

T Cell ◽

Acute Hepatitis ◽

Antiviral Therapy ◽

Cd4 T Cells ◽

T Cell Responses ◽

Cd4 T Cell ◽

Acute Hepatitis C ◽

Cell Responses

Vigorous proliferative CD4+ T cell responses are the hallmark of spontaneous clearance of acute hepatitis C virus (HCV) infection, whereas comparable responses are absent in chronically evolving infection. Here, we comprehensively characterized the breadth, specificity, and quality of the HCV-specific CD4+ T cell response in 31 patients with acute HCV infection and varying clinical outcomes. We analyzed in vitro T cell expansion in the presence of interleukin-2, and ex vivo staining with HCV peptide-loaded MHC class II tetramers. Surprisingly, broadly directed HCV-specific CD4+ T cell responses were universally detectable at early stages of infection, regardless of the clinical outcome. However, persistent viremia was associated with early proliferative defects of the HCV-specific CD4+ T cells, followed by rapid deletion of the HCV-specific response. Only early initiation of antiviral therapy was able to preserve CD4+ T cell responses in acute, chronically evolving infection. Our results challenge the paradigm that HCV persistence is the result of a failure to prime HCV-specific CD4+ T cells. Instead, broadly directed HCV-specific CD4+ T cell responses are usually generated, but rapid exhaustion and deletion of these cells occurs in the majority of patients. The data further suggest a short window of opportunity to prevent the loss of CD4+ T cell responses through antiviral therapy.

Download Full-text

Plasmacytoid dendritic cells have divergent effects on HIV infection of initial target cells and induce a pro-retention phenotype

PLoS Pathogens ◽

10.1371/journal.ppat.1009522 ◽

2021 ◽

Vol 17 (4) ◽

pp. e1009522

Author(s):

Orion Tong ◽

Gabriel Duette ◽

Thomas Ray O’Neil ◽

Caroline M. Royle ◽

Hafsa Rana ◽

...

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

Hiv Infection ◽

Reverse Transcriptase ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

Target Cells ◽

Ccr5 Expression ◽

Memory Cd4 T Cells

Although HIV infection inhibits interferon responses in its target cells in vitro, interferon signatures can be detected in vivo soon after sexual transmission, mainly attributed to plasmacytoid dendritic cells (pDCs). In this study, we examined the physiological contributions of pDCs to early HIV acquisition using coculture models of pDCs with myeloid DCs, macrophages and the resting central, transitional and effector memory CD4 T cell subsets. pDCs impacted infection in a cell-specific manner. In myeloid cells, HIV infection was decreased via antiviral effects, cell maturation and downregulation of CCR5 expression. In contrast, in resting memory CD4 T cells, pDCs induced a subset-specific increase in intracellular HIV p24 protein expression without any activation or increase in CCR5 expression, as measured by flow cytometry. This increase was due to reactivation rather than enhanced viral spread, as blocking HIV entry via CCR5 did not alter the increased intracellular p24 expression. Furthermore, the load and proportion of cells expressing HIV DNA were restricted in the presence of pDCs while reverse transcriptase and p24 ELISA assays showed no increase in particle associated reverse transcriptase or extracellular p24 production. In addition, PDCs also markedly induced the expression of CD69 on infected CD4 T cells and other markers of CD4 T cell tissue retention. These phenotypic changes showed marked parallels with resident memory CD4 T cells isolated from anogenital tissue using enzymatic digestion. Production of IFNα by pDCs was the main driving factor for all these results. Thus, pDCs may reduce HIV spread during initial mucosal acquisition by inhibiting replication in myeloid cells while reactivating latent virus in resting memory CD4 T cells and retaining them for immune clearance.

Download Full-text

A mathematical model of HIV dynamics treated with a population of gene-edited haematopoietic progenitor cells exhibiting threshold phenomenon

Mathematical Medicine and Biology A Journal of the IMA ◽

10.1093/imammb/dqz011 ◽

2019 ◽

Vol 37 (2) ◽

pp. 212-242 ◽

Cited By ~ 1

Author(s):

Vardayani Ratti ◽

Seema Nanda ◽

Susan K Eszterhas ◽

Alexandra L Howell ◽

Dorothy I Wallace

Keyword(s):

Mathematical Model ◽

T Cells ◽

T Cell ◽

Hiv Infection ◽

Progenitor Cells ◽

Cd4 T Cells ◽

Gene Editing ◽

Cd4 T Cell ◽

Threshold Phenomenon ◽

Cell Counts

Abstract The use of gene-editing technology has the potential to excise the CCR5 gene from haematopoietic progenitor cells, rendering their differentiated CD4-positive (CD4+) T cell descendants HIV resistant. In this manuscript, we describe the development of a mathematical model to mimic the therapeutic potential of gene editing of haematopoietic progenitor cells to produce a class of HIV-resistant CD4+ T cells. We define the requirements for the permanent suppression of viral infection using gene editing as a novel therapeutic approach. We develop non-linear ordinary differential equation models to replicate HIV production in an infected host, incorporating the most appropriate aspects found in the many existing clinical models of HIV infection, and extend this model to include compartments representing HIV-resistant immune cells. Through an analysis of model equilibria and stability and computation of $R_0$ for both treated and untreated infections, we show that the proposed therapy has the potential to suppress HIV infection indefinitely and return CD4+ T cell counts to normal levels. A computational study for this treatment shows the potential for a successful ‘functional cure’ of HIV. A sensitivity analysis illustrates the consistency of numerical results with theoretical results and highlights the parameters requiring better biological justification. Simulations of varying level production of HIV-resistant CD4+ T cells and varying immune enhancements as the result of these indicate a clear threshold response of the model and a range of treatment parameters resulting in a return to normal CD4+ T cell counts.

Download Full-text

Differential Expression of Activation Markers by Mycobacterium tuberculosis-specific CD4+ T Cell Distinguishes Extrapulmonary From Pulmonary Tuberculosis and Latent Infection

Clinical Infectious Diseases ◽

10.1093/cid/ciz1070 ◽

2019 ◽

Vol 71 (8) ◽

pp. 1905-1911 ◽

Cited By ~ 8

Author(s):

Paulo S Silveira-Mattos ◽

Beatriz Barreto-Duarte ◽

Beatriz Vasconcelos ◽

Kiyoshi F Fukutani ◽

Caian L Vinhaes ◽

...

Keyword(s):

T Cells ◽

Mycobacterium Tuberculosis ◽

T Cell ◽

Hiv Infection ◽

Cd4 T Cells ◽

Cell Activation ◽

Cd4 T Cell ◽

Activation Markers ◽

Timely Initiation ◽

Latent Tb

Abstract Background Diagnosis of active tuberculosis (ATB) currently relies on detection of Mycobacterium tuberculosis (Mtb). Identifying patients with extrapulmonary TB (EPTB) remains challenging because microbiological confirmation is often not possible. Highly accurate blood-based tests could improve diagnosis of both EPTB and pulmonary TB (PTB) and timely initiation of anti-TB therapy. Methods A case-control study was performed using discriminant analyses to validate an approach using Mtb-specific CD4+T-cell activation markers in blood to discriminate PTB and EPTB from latent TB infection (LTBI) as well as EPTB from PTB in 270 Brazilian individuals. We further tested the effect of human immunodeficiency virus (HIV) coinfection on diagnostic performance. Frequencies of interferon-γ +CD4+T cells expressing CD38, HLADR, and/or Ki67 were assessed by flow cytometry. Results EPTB and PTB were associated with higher frequencies of CD4+T cells expressing CD38, HLADR, or Ki67 compared with LTBI (all P values < .001). Moreover, frequencies of HLADR+ (P = .03) or Ki67+ (P < .001) cells accurately distinguished EPTB from PTB. HIV infection did not affect the capacity of these markers to distinguish ATB from LTBI or EPTB from PTB. Conclusions Cell activation markers in Mtb-specific CD4+T cells distinguished ATB from LTBI and EPTB from PTB, regardless of HIV infection status. These parameters provide an attractive approach for developing blood-based diagnostic tests for both active and latent TB.

Download Full-text

Relation of CD4+CD25+ Regulatory T Cells to Immune Status in Patients with HIV Infection.

Blood ◽

10.1182/blood.v104.11.3106.3106 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3106-3106

Author(s):

Sachi Tsunemi ◽

Tsuyoshi Iwasaki ◽

Takehito Imado ◽

Satoshi Higasa ◽

Eizo Kakishita ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Responses ◽

Hiv Infection ◽

Peripheral Blood ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

Healthy Controls ◽

Cell Counts ◽

Hiv 1

Abstract Human immunodeficiency virus (HIV) infection is characterized by marked defects in CD4+ helper T cell (Th) functions that commonly progress to a substantial decline in peripheral CD4+ T cell counts. However, the mechanisms responsible for the loss of Th functions in HIV-infected patients independent of CD4+ T cell counts remains unclear. CD4+CD25+ regulatory T cells (T Reg) are essential for down-regulation of both autoreactive and alloreactive T cells. Therefore, we decided to investigate the role of T Reg in immune status of HIV-infected patients. We examined the expression of cell surface CD25, cytoplasmic IL-4 and cytoplasmic IFN-gamma in peripheral blood CD4+ T cells from both healthy controls (n=9) and HIV-infected patients (n=43). We also compared T Reg functions between the 2 groups. CD4+CD25+ T Reg isolated from both HIV-infected patients and healthy controls strongly expressed CD45RO, HLA-DR, and FoxP3, and suppressed the proliferation of CD4+CD25− T cells, suggesting that CD4+CD25+ T cells from both healthy controls and HIV-infected patients possess phenotypic and functional characteristics of Treg. CD4+CD25high T cells are a subset of circulating CD4+CD25+ T cells in normal humans and exhibit strong in vitro regulatory functions similar to those reported for murine CD4+CD25+ T Reg. We measured the frequency of CD4+CD25high T Reg by analysis of surface CD25 on CD4+ T cells in peripheral blood samples. We also examined Th1 and Th2 frequencies by analysis of cytoplasmic IFN-gamma and IL-4 levels in CD4+ T cells. T Reg from HIV-infected patients with detectable plasma HIV-1 RNA showed a statistically significant increase in CD4+CD25high cell frequency (p<0.05) compared to healthy controls, with T Reg frequencies inversely proportional to CD4+ T cell numbers (p<0.01). However, in HIV-infected patients with undetectable plasma HIV-RNA, frequencies of CD4+CD25high T Reg were not increased and not related to CD4+ T cell numbers. In both HIV-infected patient groups, T Reg frequency was inversely related to Th1 frequency (detectable: p<0.05, undetectable: p<0.001), but positively related to Th2 frequency (detectable: p<0.01, undetectable: p<0.001). Our results indicate that increased frequencies of peripheral blood T Reg were related to disease progression as measured by detectable plasma HIV-1 RNA, decreased peripheral blood CD4+ T cell counts, and polarization toward Th2 immune responses in HIV-infected patients. HIV infection may lead to induction of T reg that inhibit antiviral immune responses, resulting in the progression of the disease. Manipulation of T Reg could help restore antiviral immune responses in HIV infection, and prevent the progression of HIV infection.

Download Full-text