A novel mechanism for HIV1-mediated bystander CD4+ T-cell death: neighboring dying cells drive the capacity of HIV1 to kill noncycling primary CD4+ T cells

Abstract Background and aims Sustained activation of CD4+ T cells plays important roles in the pathogenesis of Crohn’s disease [CD]. Under physiologic conditions, activated T cells can be timely eliminated by a process termed activation-induced cell death [AICD], restraining T cell over-activation and preventing immunological destruction. We inquired whether defective AICD might explain CD4+ T cell over-activation in CD and investigated the underlying mechanisms. Methods CD14+ macrophages [Mφ] and CD4+ T cells were isolated from intestinal tissues or peripheral blood of controls and CD patients. An ex vivo evaluation system was employed to simulate AICD and cell apoptosis was measured by flow cytometry. Results CD4+ T cells from CD patients fail to undergo AICD in the ex vivo system. Specifically, proinflammatory type 1 helper T [Th1] and type 17 helper T [Th17] cells, rather than immunosuppressive regulatory T [Treg] cells evade AICD in CD. CD14+ Mφ in the intestinal inflammatory microenvironment of CD promote AICD resistance in CD4+ T cells via a cell-to-cell contact-independent manner. Mechanistically, CD14+ Mφ released exosomes express membrane tumour necrosis factor [TNF] which engages TNFR2 on CD4+ T cells and triggers NF-κB signalling, thereby causing AICD resistance. Importantly, clinically applicable anti-TNF antibodies effectively blocked exosomal membrane TNF-induced CD4+ T cell AICD resistance. Conclusions CD14+ Mφ participate in CD pathogenesis by inducing AICD resistance through release of exosomal membrane TNF to activate the TNFR2/NF-κB pathway in CD4+ T cells. These results present new insights into CD pathogenesis and extend mechanistic understanding of anti-TNF agents. Proposed model CD14+ Mφ in the intestinal microenvironment of CD patients maintain the sustained activation of CD4+ T cells through exosomal membrane TNF to induce apoptosis resistance via TNFR2/NF-κB signalling, which could be effectively blocked by clinically applicable anti-TNF agents.

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Activation-induced death by apoptosis in CD4+ T cells from human immunodeficiency virus-infected asymptomatic individuals.

Journal of Experimental Medicine ◽

10.1084/jem.175.2.331 ◽

1992 ◽

Vol 175 (2) ◽

pp. 331-340 ◽

Cited By ~ 605

Author(s):

H Groux ◽

G Torpier ◽

D Monté ◽

Y Mouton ◽

A Capron ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

Cell Death ◽

T Cell ◽

Cell Population ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

Death Process ◽

Immunodeficiency Virus ◽

Asymptomatic Individuals

In immature thymocytes, T cell receptor for antigen (TCR) mobilization leads to an active T cell suicide process, apoptosis, which is involved in the selection of the T cell repertoire. We have proposed that inappropriate induction of such a cell death program in the mature CD4+ T cell population could account for both early qualitative and late quantitative CD4+ T lymphocyte defects of human immunodeficiency virus (HIV)-infected individuals (Ameisen, J.C., and A. Capron. 1991. Immunol. Today. 4:102). Here, we report that the selective failure of CD4+ T cells from 59 clinically asymptomatic HIV-infected individuals to proliferate in vitro to TCR mobilization by major histocompatibility complex class II-dependent superantigens and to pokeweed mitogen (PWM) is due to an active CD4+ T cell death process, with the biochemical and ultrastructural features of apoptosis. Activation-induced cell death occurred only in the CD4+ T cell population from HIV-infected asymptomatic individuals and was not observed in T cells from any of 58 HIV-seronegative controls, including nine patients with other acute or chronic infectious diseases. Activation-induced CD4+ T cell death was prevented by cycloheximide, cyclosporin A, and a CD28 monoclonal antibody (mAb). The CD28 mAb not only prevented apoptosis but also restored T cell proliferation to stimuli, including PWM, superantigens, and the tetanus and influenza recall antigens. These findings may have implications for the understanding of the pathogenesis of acquired immune deficiency syndrome and for the design of specific therapeutic strategies.

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HIV-2 Depletes CD4 T Cells through Pyroptosis despite Vpx-Dependent Degradation of SAMHD1

Journal of Virology ◽

10.1128/jvi.00666-19 ◽

2019 ◽

Vol 93 (24) ◽

Cited By ~ 1

Author(s):

Xiaoyu Luo ◽

Eytan Herzig ◽

Gilad Doitsh ◽

Zachary W. Grimmett ◽

Isa Muñoz-Arias ◽

...

Keyword(s):

T Cells ◽

Cell Death ◽

T Cell ◽

Gene Product ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

Restriction Factor ◽

Abortive Infection ◽

Caspase 1 ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 2 (HIV-2) infection results in a milder course of disease and slower progression to AIDS than does HIV-1. We hypothesized that this difference may be due to degradation of the sterile alpha motif and HD domain 1 (SAMHD1) host restriction factor by the HIV-2 Vpx gene product, thereby diminishing abortive infection and pyroptotic cell death within bystander CD4 T cells. We have compared CD4 T cell death in tonsil-derived human lymphoid aggregate cultures (HLACs) infected with wild-type HIV-2, HIV-2 ΔVpx, or HIV-1. In contrast to our hypothesis, HIV-2, HIV-2 ΔVpx, and HIV-1 induced similar levels of bystander CD4 T cell death. In all cases, cell death was blocked by AMD3100, a CXCR4 entry inhibitor, but not by raltegravir, an integrase, indicating that only early life cycle events were required. Cell death was also blocked by a caspase-1 inhibitor, a key enzyme promoting pyroptosis, but not by a caspase-3 inhibitor, an important enzyme in apoptosis. HIV-1-induced abortive infection and pyroptotic cell death were also not reduced by forced encapsidation of HIV-2 Vpx into HIV-1 virions. Together, these findings indicate that HIV-2 and HIV-1 support similar levels of CD4 T cell depletion in vitro despite HIV-2 Vpx-mediated degradation of the SAMHD1 transcription factor. The milder disease course observed with HIV-2 infection likely stems from factors other than abortive infection and caspase-1-dependent pyroptosis in bystander CD4 T cells. IMPORTANCE CD4 T cell depletion during HIV-1 infection involves the demise of bystander CD4 T cells due to abortive infection, viral DNA sensing, inflammasome assembly, and death by caspase-1-dependent pyroptosis. HIV-2 infection is associated with milder disease and lower rates of CD4 T cell loss. We hypothesized that HIV-2 infection produces lower levels of pyroptosis due to the action of its Vpx gene product. Vpx degrades the SAMHD1 restriction factor, potentially reducing abortive forms of infection. However, in tonsil cell cultures, HIV-2, HIV-2 ΔVpx, and HIV-1 induced indistinguishable levels of pyroptosis. Forced encapsidation of Vpx into HIV-1 virions also did not reduce pyroptosis. Thus, SAMHD1 does not appear to play a key role in the induction of bystander cell pyroptosis. Additionally, the milder clinical course of HIV-2-induced disease is apparently not explained by a decrease in this inflammatory form of programmed cell death.

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Reduced immune-regulatory molecule expression on human colonic memory CD4 T cells in older adults

Immunity & Ageing ◽

10.1186/s12979-021-00217-0 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Stephanie M. Dillon ◽

Tezha A. Thompson ◽

Allison J. Christians ◽

Martin D. McCarter ◽

Cara C. Wilson

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Older Persons ◽

Age Groups ◽

T Cell Immunity ◽

Cd4 T Cell ◽

Cell Immunity ◽

Memory Cd4 T Cells

Abstract Background The etiology of the low-level chronic inflammatory state associated with aging is likely multifactorial, but a number of animal and human studies have implicated a functional decline of the gastrointestinal immune system as a potential driver. Gut tissue-resident memory T cells play critical roles in mediating protective immunity and in maintaining gut homeostasis, yet few studies have investigated the effect of aging on human gut T cell immunity. To determine if aging impacted CD4 T cell immunity in the human large intestine, we utilized multi-color flow cytometry to measure colonic lamina propria (LP) CD4 T cell frequencies and immune-modulatory marker expression in younger (mean ± SEM: 38 ± 1.5 yrs) and older (77 ± 1.6 yrs) adults. To determine cellular specificity, we evaluated colon LP CD8 T cell frequency and phenotype in the same donors. To probe tissue specificity, we evaluated the same panel of markers in peripheral blood (PB) CD4 T cells in a separate cohort of similarly aged persons. Results Frequencies of colonic CD4 T cells as a fraction of total LP mononuclear cells were higher in older persons whereas absolute numbers of colonic LP CD4 T cells per gram of tissue were similar in both age groups. LP CD4 T cells from older versus younger persons exhibited reduced CTLA-4, PD-1 and Ki67 expression. Levels of Bcl-2, CD57, CD25 and percentages of activated CD38+HLA-DR+ CD4 T cells were similar in both age groups. In memory PB CD4 T cells, older age was only associated with increased CD57 expression. Significant age effects for LP CD8 T cells were only observed for CTLA-4 expression, with lower levels of expression observed on cells from older adults. Conclusions Greater age was associated with reduced expression of the co-inhibitory receptors CTLA-4 and PD-1 on LP CD4 T cells. Colonic LP CD8 T cells from older persons also displayed reduced CTLA-4 expression. These age-associated profiles were not observed in older PB memory CD4 T cells. The decline in co-inhibitory receptor expression on colonic LP T cells may contribute to local and systemic inflammation via a reduced ability to limit ongoing T cell responses to enteric microbial challenge.

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The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

Immuno ◽

10.3390/immuno1030008 ◽

2021 ◽

Vol 1 (3) ◽

pp. 119-131

Author(s):

Jana Palmowski ◽

Kristina Gebhardt ◽

Thomas Reichel ◽

Torsten Frech ◽

Robert Ringseis ◽

...

Keyword(s):

T Cells ◽

Oxygen Consumption ◽

T Cell ◽

Real Time ◽

Cd4 T Cells ◽

Cell Metabolism ◽

Cd4 T Cell ◽

Autologous Serum ◽

Cell Phenotype ◽

The Impact

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

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Infection of HLA-DR1 Transgenic Mice with a Human Isolate of Influenza A Virus (H1N1) Primes a Diverse CD4 T-Cell Repertoire That Includes CD4 T Cells with Heterosubtypic Cross-Reactivity to Avian (H5N1) Influenza Virus

Journal of Virology ◽

10.1128/jvi.00302-09 ◽

2009 ◽

Vol 83 (13) ◽

pp. 6566-6577 ◽

Cited By ~ 52

Author(s):

Katherine A. Richards ◽

Francisco A. Chaves ◽

Andrea J. Sant

Keyword(s):

T Cells ◽

Influenza Virus ◽

T Cell ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Cd4 T Cells ◽

Cross Reactivity ◽

Cd4 T Cell ◽

Ns1 Protein ◽

Infected Cells

ABSTRACT The specificity of the CD4 T-cell immune response to influenza virus is influenced by the genetic complexity of the virus and periodic encounters with variant subtypes and strains. In order to understand what controls CD4 T-cell reactivity to influenza virus proteins and how the influenza virus-specific memory compartment is shaped over time, it is first necessary to understand the diversity of the primary CD4 T-cell response. In the study reported here, we have used an unbiased approach to evaluate the peptide specificity of CD4 T cells elicited after live influenza virus infection. We have focused on four viral proteins that have distinct intracellular distributions in infected cells, hemagglutinin (HA), neuraminidase (NA), nucleoprotein, and the NS1 protein, which is expressed in infected cells but excluded from virion particles. Our studies revealed an extensive diversity of influenza virus-specific CD4 T cells that includes T cells for each viral protein and for the unexpected immunogenicity of the NS1 protein. Due to the recent concern about pandemic avian influenza virus and because CD4 T cells specific for HA and NA may be particularly useful for promoting the production of neutralizing antibody to influenza virus, we have also evaluated the ability of HA- and NA-specific CD4 T cells elicited by a circulating H1N1 strain to cross-react with related sequences found in an avian H5N1 virus and find substantial cross-reactivity, suggesting that seasonal vaccines may help promote protection against avian influenza virus.

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Isolevuglandin-Modified Cardiac Proteins Drive CD4+ T Cell Activation in the Heart and Promote Cardiac Dysfunction

Circulation ◽

10.1161/circulationaha.120.051889 ◽

2021 ◽

Author(s):

Njabulo Ngwenyama ◽

Annet Kirabo ◽

Mark Aronovitz ◽

Francisco Velázquez ◽

Francisco Carrillo-Salinas ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Antigen Presentation ◽

T Cell Activation ◽

Cardiac Dysfunction ◽

Cd4 T Cells ◽

Cell Activation ◽

Cd4 T Cell ◽

Myocardial Oxidative Stress

Background: Despite the well-established association between T cell-mediated inflammation and non-ischemic heart failure (HF), the specific mechanisms triggering T cell activation during the progression of HF and the antigens involved are poorly understood. We hypothesized that myocardial oxidative stress induces the formation of isolevuglandin (IsoLG)-modified proteins that function as cardiac neoantigens to elicit CD4+ T cell receptor (TCR) activation and promote HF. Methods: We used transverse aortic constriction (TAC) in mice to trigger myocardial oxidative stress and T cell infiltration. We profiled the TCR repertoire by mRNA sequencing of intramyocardial activated CD4+ T cells in Nur77 GFP reporter mice, which transiently express GFP upon TCR engagement. We assessed the role of antigen presentation and TCR specificity in the development of cardiac dysfunction using antigen presentation-deficient MhcII -/- mice, and TCR transgenic OTII mice that lack specificity for endogenous antigens. We detected IsoLG-protein adducts in failing human hearts. We also evaluated the role of reactive oxygen species (ROS) and IsoLGs in eliciting T cell immune responses in vivo by treating mice with the antioxidant TEMPOL, and the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) during TAC, and ex-vivo in mechanistic studies of CD4+ T cell proliferation in response to IsoLG-modified cardiac proteins. Results: We discovered that TCR antigen recognition increases in the left ventricle (LV) as cardiac dysfunction progresses, and identified a limited repertoire of activated CD4+ T cell clonotypes in the LV. Antigen presentation of endogenous antigens was required to develop cardiac dysfunction since MhcII -/- mice reconstituted with CD4+ T cells, and OTII mice immunized with their cognate antigen were protected from TAC-induced cardiac dysfunction despite the presence of LV-infiltrated CD4+ T cells. Scavenging IsoLGs with 2-HOBA reduced TCR activation and prevented cardiac dysfunction. Mechanistically, cardiac pressure overload resulted in ROS dependent dendritic cell accumulation of IsoLG-protein adducts which induced robust CD4+ T cell proliferation. Conclusions: Collectively, our study demonstrates an important role of ROS-induced formation of IsoLG-modified cardiac neoantigens that lead to TCR-dependent CD4+ T cell activation within the heart.

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739 Intratumor childhood vaccine-specific CD4+ T cell recall helps antitumor CD8 T cells

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.739 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A770-A770

Author(s):

Michael Brown ◽

Zachary McKay ◽

Yuanfan Yang ◽

Darell Bigner ◽

Smita Nair ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Viral Replication ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

Antitumor Efficacy ◽

Polio Vaccine ◽

Recall Antigen ◽

Childhood Vaccine

BackgroundPVSRIPO, a recombinant poliovirus derived from the live-attenuated Sabin oral polio vaccine strain, is being tested in multi-institutional phase II clinical trials for recurrent glioblastoma (NCT04479241) and unresectable, PD-1 refractory melanoma (NCT04577807) in combination with PD1 blockade. PVSRIPO capsid is identical to the Sabin vaccine strain and >99% identical to the inactivated Polio vaccine (IPOL, Salk), against which public health mandated childhood vaccination is near universal. In non-vaccinated mice, PVSRIPO mediates antitumor efficacy in a replication-dependent manner via engaging innate inflammation and antitumor T cells. Accordingly, it is anticipated that pre-existing immunity to PVSRIPO impedes antitumor therapy. However, recent evidence indicates that immunological 'recall', or reactivation of memory T cells, may mediate anti-tumor effects.MethodsThe impact of prior polio vs control (KLH) vaccination on intratumor viral replication, tumor inflammation, and overall tumor growth after intratumor PVSRIPO therapy was assessed in murine tumor models. The role of polio capsid and tetanus recall antigens in mediating intratumor inflammation and antitumor efficacy was similarly studied in mice non-permissive to PVSRIPO infection. To mechanistically define antitumor effects of polio recall, B cell and CD8 T cell knockout mice were used, in addition to adoptive transfer of CD4+ T cells from vaccinated mice. Intratumor polio or tetanus recall antigen therapy was performed after OT-I transfer (OVA-specific T cells) in the B16-OVA melanoma model to gauge antitumor T cell activity. Lastly, the inflammatory effects of polio and tetanus antigens was tested in human peripheral blood mononuclear cells (PBMCs).ResultsDespite curtailing intratumor viral replication, prior polio vaccination in mice potentiated subsequent antitumor efficacy of PVSRIPO. Intratumor recall responses induced by polio and tetanus antigens also delayed tumor growth. Recall antigen therapy was associated with marked intratumor influx of eosinophils, conventional CD4+ T cells, and increased expression of IFN-g, TNF, and Granzyme B in tumor infiltrating T cells. The antitumor efficacy of polio recall antigen was mediated by CD4+ T cells, partially depended upon CD8+ T cells, and was impaired by B cells. Both polio and tetanus recall antigen therapy bolstered the antitumor function of tumor-specific OT-I CD8+ T cells. Polio and tetanus antigens induced CXCL10 and type I/II/III IFNs in PBMCs in vitro.ConclusionsChildhood vaccine-specific CD4+ T cells hold cancer immunotherapy potential. In the context of PVSRIPO therapy, antitumor and inflammatory effects of polio vaccine-specific CD4+ T cell recall supersedes inhibitory effects of attenuated intratumor viral replication, and represents a novel mechanism of action.Ethics ApprovalThe animal work described in this study was approved by the Duke University IACUC.

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CD4+ T cells specific for glycoprotein B from cytomegalovirus exhibit extreme conservation of T-cell receptor usage between different individuals

Blood ◽

10.1182/blood-2007-04-079863 ◽

2008 ◽

Vol 111 (4) ◽

pp. 2053-2061 ◽

Cited By ~ 25

Author(s):

Laura Crompton ◽

Naeem Khan ◽

Rajiv Khanna ◽

Laxman Nayak ◽

Paul A. H. Moss

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Receptor ◽

Cell Response ◽

Cd4 T Cells ◽

Clonal Selection ◽

Cell Receptor ◽

T Cell Response ◽

Cd4 T Cell ◽

Extreme Conservation

Antigen-specific CD8+ cytotoxic T cells often demonstrate extreme conservation of T-cell receptor (TCR) usage between different individuals, but similar characteristics have not been documented for CD4+ T cells. CD4+ T cells predominantly have a helper immune role, but a cytotoxic CD4+ T-cell subset has been characterized, and we have studied the cytotoxic CD4+ T-cell response to a peptide from human cytomegalovirus glycoprotein B presented through HLA-DRB*0701. We show that this peptide elicits a cytotoxic CD4+ T-cell response that averages 3.6% of the total CD4+ T-cell repertoire of cytomegalovirus-seropositive donors. Moreover, CD4+ cytotoxic T-cell clones isolated from different individuals exhibit extensive conservation of TCR usage, which indicates strong T-cell clonal selection for peptide recognition. Remarkably, this TCR sequence was recently reported in more than 50% of cases of CD4+ T-cell large granular lymphocytosis. Immunodominance of cytotoxic CD4+ T cells thus parallels that of CD8+ subsets and suggests that cytotoxic effector function is critical to the development of T-cell clonal selection, possibly from immune competition secondary to lysis of antigen-presenting cells. In addition, these TCR sequences are highly homologous to those observed in HLA-DR7+ patients with CD4+ T-cell large granular lymphocytosis and implicate cytomegalovirus as a likely antigenic stimulus for this disorder.

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IL-6 enhances CD4 cell motility by sustaining mitochondrial Ca2+ through the noncanonical STAT3 pathway

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2103444118 ◽

2021 ◽

Vol 118 (37) ◽

pp. e2103444118

Author(s):

Felipe Valença-Pereira ◽

Qian Fang ◽

Isabelle J. Marié ◽

Emily L. Giddings ◽

Karen A. Fortner ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Motility ◽

Cd4 T Cells ◽

Cell Function ◽

Inflammatory Diseases ◽

Cd4 T Cell ◽

Noncanonical Pathway ◽

Cd4 Cell ◽

Intrinsic Effect

Interleukin 6 (IL-6) is known to regulate the CD4 T cell function by inducing gene expression of a number of cytokines through activation of Stat3 transcription factor. Here, we reveal that IL-6 strengthens the mechanics of CD4 T cells. The presence of IL-6 during activation of mouse and human CD4 T cells enhances their motility (random walk and exploratory spread), resulting in an increase in travel distance and higher velocity. This is an intrinsic effect of IL-6 on CD4 T-cell fitness that involves an increase in mitochondrial Ca2+. Although Stat3 transcriptional activity is dispensable for this process, IL-6 uses mitochondrial Stat3 to enhance mitochondrial Ca2+-mediated motility of CD4 T cells. Thus, through a noncanonical pathway, IL-6 can improve competitive fitness of CD4 T cells by facilitating cell motility. These results could lead to alternative therapeutic strategies for inflammatory diseases in which IL-6 plays a pathogenic role.

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