scholarly journals Platelets function as an acute viral reservoir during HIV-1 infection by harboring virus and T-cell complex formation

2020 ◽  
Vol 4 (18) ◽  
pp. 4512-4521
Author(s):  
Sydney R. Simpson ◽  
Meera V. Singh ◽  
Stephen Dewhurst ◽  
Giovanni Schifitto ◽  
Sanjay B. Maggirwar
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Complex Formation ◽  
Platelet Activation ◽  
Cd4 T Cells ◽  
Cell Complex ◽  
Cd4 T Cell ◽  
Cell Recovery

Abstract Platelets were recently found to harbor infectious HIV virions in infected individuals who are on antiretroviral treatment with poor CD4+ T-cell recovery. In this study, we screened platelets from recently infected individuals, before and after antiretroviral therapy, for the presence of virus and examined platelet activation, as well as CD4+ T-cell recovery. This was followed by in vitro studies assessing platelet–CD4+ T-cell complex formation as a contributing factor to viral transmission. HIV+ platelets were detected in 10 of 10 acutely infected individuals with no prior history of antiretroviral therapy. The percentage of HIV+ platelets dropped significantly after 3 months of antiretroviral therapy in all of the study participants. These individuals also demonstrated significant recovery of CD4+ T cells. Interestingly, the percentage of HIV+ platelets correlated positively with viral load but not with CD4+ T-cell count. Furthermore, we found that platelet activation with soluble CD40L or thrombin receptor activator peptide 6 (TRAP6) increased platelet-virus interactions in vitro. TRAP6-mediated interactions were reduced by platelet antagonists, aspirin, and R406. We demonstrated that platelets transmit the virus to CD4+ T cells, and this transinfection was abolished by inhibiting platelet–T-cell complex formation via exposure to an anti-CD62P antibody. Additionally, treatment with TRAP6 significantly increased the transinfection, which was also inhibited by aspirin and R206. These results reveal that platelets have the potential to promote HIV viral spread during the acute stage of infection, by harboring infectious virus transmitting infection to susceptible CD4+ T cells through complex formation.

scholarly journals Kinetics of CD4+ T-cell recovery amongst HIV load suppressed patients on first-line antiretroviral therapy in Yaoundé, Cameroon

2021 ◽  
Vol 15 (3) ◽  
pp. 881-888
Author(s):  
Cedric Happi Mbakam ◽  
Julius Mbekem Nwobegahay ◽  
Cybelle Fodieu Mezajou ◽  
Franklin Agueguia Azebaze ◽  
Leopold Mbous Nguimbus ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Cd4 T Cells ◽  
Standard Form ◽  
University Teaching ◽  
Cd4 T Cell ◽  
Cell Recovery ◽  
First Line ◽  
Kinetics Of

HIV infected patients on Antiretroviral Therapy (ART) are exposed to various immunological disorders. Immune reconstitution is one of the most challenging problem linked to morbidity and mortality in HIV patients. This study aimed at evaluating the kinetics of CD4+ T-cell recovery amongst HIV load suppressed patients on first-line ART in Yaoundé, Cameroon. This was a retrospective cohort study performed at the care and treatment units of the Yaoundé University Teaching Hospital and Essos Hospital Center, with viral suppressed patients initiated on ART between March and July 2015. Data were collected using a standard form and analyzed using R.3.6.2 software. A p<0.05 was considered statistically significant for a 95%CI. Of the 499 viral suppressed participants, 32% (n=160) were male and 68% (n=339) female; 33% and 40% had severe and moderate immunodepression at baseline, respectively; 9% and 28% remain respectively on the same immunological state. CD4+ T-cell count increased by 73%, 49% and 29% for patients that started treatment, with CD4+ <150 cells/ml, 150<CD4+<350 cells/ml and 350<CD4+<500 cells/ml, respectively and 14%, 34% and 40% reached a target of 500 cells/ml or more after 4 years of treatment. Elder patients and males were likely to have CD4+ T-cells less than 350 Cells/ml. Approximately 35% of patient started treatment with CD4+ T-cells <350 Cells/ml. CD4+ T-cells increased significantly during 4 years of treatment but, just 29% in average achieved CD4+ ≥ 500 cells/ml. CD4 T-cells recovery represent and important challenge in the immunological monitoring of long-term HIV infected patients on ART.

scholarly journals Contact-dependent delivery of IL-2 by dendritic cells to CD4 T cells in the contraction phase promotes their long-term survival

2019 ◽  
Vol 11 (2) ◽  
pp. 108-123
Author(s):  
Dan Tong ◽  
Li Zhang ◽  
Fei Ning ◽  
Ying Xu ◽  
Xiaoyu Hu ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
Immune Memory ◽  
Term Survival

Abstract Common γ chain cytokines are important for immune memory formation. Among them, the role of IL-2 remains to be fully explored. It has been suggested that this cytokine is critically needed in the late phase of primary CD4 T cell activation. Lack of IL-2 at this stage sets for a diminished recall response in subsequent challenges. However, as IL-2 peak production is over at this point, the source and the exact mechanism that promotes its production remain elusive. We report here that resting, previously antigen-stimulated CD4 T cells maintain a minimalist response to dendritic cells after their peak activation in vitro. This subtle activation event may be induced by DCs without overt presence of antigen and appears to be stronger if IL-2 comes from the same dendritic cells. This encounter reactivates a miniature IL-2 production and leads a gene expression profile change in these previously activated CD4 T cells. The CD4 T cells so experienced show enhanced reactivation intensity upon secondary challenges later on. Although mostly relying on in vitro evidence, our work may implicate a subtle programing for CD4 T cell survival after primary activation in vivo.

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

Lab on a Chip ◽  
2016 ◽  
Vol 16 (3) ◽  
pp. 506-514 ◽  
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.

scholarly journals African Green Monkey TRIM5α Restriction in Simian Immunodeficiency Virus-Specific Rhesus Macaque Effector CD4 T Cells Enhances Their Survival and Antiviral Function

2015 ◽  
Vol 89 (8) ◽  
pp. 4449-4456 ◽  
Author(s):  
Sumiti Jain ◽  
Matthew T. Trivett ◽  
Victor I. Ayala ◽  
Claes Ohlen ◽  
David E. Ott
Keyword(s):  
T Cells ◽  
T Cell ◽  
Rhesus Macaque ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
T Cell Clones ◽  
Cell Clones ◽  
Immunodeficiency Virus ◽  
Antiviral Function

ABSTRACTThe expression of xenogeneic TRIM5α proteins can restrict infection in various retrovirus/host cell pairings. Previously, we have shown that African green monkey TRIM5α (AgmTRIM5α) potently restricts both human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus mac239 (SIVmac239) replication in a transformed human T-cell line (L. V. Coren, et al., Retrovirology 12:11, 2015,http://dx.doi.org/10.1186/s12977-015-0137-9). To assess AgmTRIM5α restriction in primary cells, we transduced AgmTRIM5α into primary rhesus macaque CD4 T cells and infected them with SIVmac239. Experiments with T-cell clones revealed that AgmTRIM5α could reproducibly restrict SIVmac239replication, and that this restriction synergizes with an intrinsic resistance to infection present in some CD4 T-cell clones. AgmTRIM5α transduction of virus-specific CD4 T-cell clones increased and prolonged their ability to suppress SIV spread in CD4 target cells. This increased antiviral function was strongly linked to decreased viral replication in the AgmTRIM5α-expressing effectors, consistent with restriction preventing the virus-induced cytopathogenicity that disables effector function. Taken together, our data show that AgmTRIM5α restriction, although not absolute, reduces SIV replication in primary rhesus CD4 T cells which, in turn, increases their antiviral function. These results support priorin vivodata indicating that the contribution of virus-specific CD4 T-cell effectors to viral control is limited due to infection.IMPORTANCEThe potential of effector CD4 T cells to immunologically modulate SIV/HIV infection likely is limited by their susceptibility to infection and subsequent inactivation or elimination. Here, we show that AgmTRIM5α expression inhibits SIV spread in primary effector CD4 T cellsin vitro. Importantly, protection of effector CD4 T cells by AgmTRIM5α markedly enhanced their antiviral function by delaying SIV infection, thereby extending their viability despite the presence of virus. Ourin vitrodata support priorin vivoHIV-1 studies suggesting that the antiviral CD4 effector response is impaired due to infection and subsequent cytopathogenicity. The ability of AgmTRIM5α expression to restrict SIV infection in primary rhesus effector CD4 T cells now opens an opportunity to use the SIV/rhesus macaque model to further elucidate the potential and scope of anti-AIDS virus effector CD4 T-cell function.

scholarly journals CD161 Expression on Mucosa-Associated Invariant T Cells is Reduced in HIV-Infected Subjects Undergoing Antiretroviral Therapy Who Do Not Recover CD4+ T Cells

2017 ◽  
Vol 2 (3) ◽  
pp. 335 ◽  
Author(s):  
Michael L Freeman ◽  
Stephen R. Morris ◽  
Michael M. Lederman
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Mucosal Immune Response ◽  
Cell Recovery ◽  
Viral Control ◽  
Mait Cells ◽  
Mucosal Tissues ◽  
Immune Failure

Background: Mucosa-associated invariant T (MAIT) cells are a recently identified class of innate-like T cells that are involved in the mucosal immune response. MAIT cells are characterized by expression of TCR Va7.2 and CD161. In HIV infection, there is a profound early loss of MAIT cells from the circulation that never fully recovers, even after prolonged viral control with antiretroviral therapy (ART).Methods: We analyzed PBMCs from fresh whole blood from HIV-negative or ART-treated HIV-positive donors with full (Immune Success) or impaired (Immune Failure) CD4+ T- cell recovery by flow cytometry for T-cell markers, TCR Va7.2, and CD161. The PBMCs were cultured with or without TCR-mediated stimulation, and CD161 expression was assessed on Va7.2+ T cells. Interferon-g (IFNg) production was assessed by intracellular cytokine staining.Results: We found a decrease in the percentage of CD3+ T cells that expressed CD161 and the percentage of Va7.2+ T cells that expressed CD161, in HIV-infected individuals. We also found a significant increase in the percentage of T cells that were Va7.2+CD161- in immune failure compared to controls, accompanied by an increase in the percentage of Va7.2+CD161- T cells that express CD8+ in donors with immune failure, but not immune success. After TCR stimulation in vitro, Va7.2+ T cells reduced expression of CD161, yet Va7.2+ CD161- cells from immune failure donors retained the ability to express IFNg on stimulation.Conclusions: Our findings suggest that in immune failure patients, the reduction in peripheral MAIT cells is due, at least in part, to a loss in CD161 expression, and is not merely the result of trafficking into mucosal tissues or cell death. These CD161- cells retain their function.

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

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.

Age-Related Induction of CD4+ T-Cell Unresponsiveness Is Reversible and Dependant of the Host’s Environment.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3925-3925
Author(s):  
Pedro Horna ◽  
Rahul Chavan ◽  
Jason Brayer ◽  
Ildefonso Suarez ◽  
Eduardo M. Sotomayor
Keyword(s):  
T Cells ◽  
T Cell ◽  
Transgenic Mice ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Cell Compartment ◽  
Memory Phenotype ◽  
Age Related ◽  
And Function

Abstract A large number of CD4+ T-cells from either aged mice or humans display surface markers associated with an activated/memory phenotype. In spite of these changes however, these T-cells have a markedly decreased ability to proliferate and produce IL-2 in response to antigen stimulation in vitro. The cellular and molecular mechanisms involved in this age-related unresponsiveness of the CD4+ T-cell compartment remain poorly understood. Utilizing a well-established experimental system in which transgenic CD4+ T cells specific for a MHC class II restricted epitope of influenza hemagglutinin (HA) are adoptively transferred into non-transgenic recipients, we have previously elucidated important mechanisms involved in the induction and maintenance of CD4+ T-cell tolerance. Our studies were however limited to the analysis of T-cell function in lymphoma bearing young mice (4 to 10 weeks old). Here, we assessed the influence of the aged microenvironment in determining the phenotype and function of antigen-specific T-cells. CD4+ T-cells from young TCR transgenic mice (2 months old) were adoptively transferred into either old (20–24 months) or young (2 months old) non-transgenic mice. Two weeks later, clonotypic and non-clonotypic CD4+ T-cells were isolated from the spleens of these animals and their phenotype and function were determined in vitro. Reminiscent of the age-related changes observed within the normal CD4+ T-cell repertoire, young transgenic T-cells transferred into aged hosts have acquired an activated/memory phenotype but displayed a significant impairment in antigen-specific proliferation and IL-2 production in response to cognate antigen in vitro. These changes were not due to homeostatic proliferation of the transferred T-cells into the relatively lymphopenic aged host. To determine whether the changes observed in “aged” T-cells were reversible or not, we adoptively transfer old T-cells back into young hosts or into control old mice. While old transgenic T-cells transferred into an old environment remained fully unresponsive, the adoptive transfer of the same old T-cells into a young host restored their ability to proliferate and produce IL-2. Surprisingly, these “old” T-cells were able to produce significantly higher levels of IFN-gamma indicative of their memory/effector phenotype. Furthermore, young animals adoptively transferred with “aged” antigen-specific T-cells were now capable of rejecting A20 B-cell lymphomas expressing HA as a model tumor antigen (A20HA). Taking together, factor(s) present in the aged microenvironment are responsible for limiting the effector function of CD4+ T-cells that seem otherwise well equipped to become fully activated if the proper environment is provided (young microenvironment). The potential role of soluble suppressive factors as well as regulatory T-cells (Tregs) in the unresponsiveness observed in the T-cell compartment of aged hosts will be discussed.

scholarly journals Reconstitution of CD4 T Cells in Bronchoalveolar Lavage Fluid after Initiation of Highly Active Antiretroviral Therapy

2010 ◽  
Vol 84 (18) ◽  
pp. 9010-9018 ◽  
Author(s):  
Kenneth S. Knox ◽  
Carol Vinton ◽  
Chadi A. Hage ◽  
Lisa M. Kohli ◽  
Homer L. Twigg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Bronchoalveolar Lavage ◽  
Highly Active Antiretroviral Therapy ◽  
Cd4 T Cells ◽  
Lavage Fluid ◽  
Cd4 T Cell ◽  
Highly Active ◽  
Before And After

ABSTRACT The massive depletion of gastrointestinal-tract CD4 T cells is a hallmark of the acute phase of HIV infection. In contrast, the depletion of the lower-respiratory-tract mucosal CD4 T cells as measured in bronchoalveolar lavage (BAL) fluid is more moderate and similar to the depletion of CD4 T cells observed in peripheral blood (PB). To understand better the dynamics of disease pathogenesis and the potential for the reconstitution of CD4 T cells in the lung and PB following the administration of effective antiretroviral therapy, we studied cell-associated viral loads, CD4 T-cell frequencies, and phenotypic and functional profiles of antigen-specific CD4 T cells from BAL fluid and blood before and after the initiation of highly active antiretroviral therapy (HAART). The major findings to emerge were the following: (i) BAL CD4 T cells are not massively depleted or preferentially infected by HIV compared to levels for PB; (ii) BAL CD4 T cells reconstitute after the initiation of HAART, and their infection frequencies decrease; (iii) BAL CD4 T-cell reconstitution appears to occur via the local proliferation of resident BAL CD4 T cells rather than redistribution; and (iv) BAL CD4 T cells are more polyfunctional than CD4 T cells in blood, and their functional profile is relatively unchanged after the initiation of HAART. Taken together, these data suggest mechanisms for mucosal CD4 T-cell depletion and interventions that might aid in the reconstitution of mucosal CD4 T cells.

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