scholarly journals The New Old CD8+ T Cells in the Immune Paradox of Pregnancy

2021 ◽  
Vol 12 ◽  
Author(s):  
Lilja Hardardottir ◽  
Maria Victoria Bazzano ◽  
Laura Glau ◽  
Luca Gattinoni ◽  
Angela Köninger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Biology ◽  
Immune Cell ◽  
Cd8 T Cell ◽  
Therapeutic Interventions ◽  
Effector Memory ◽  
Pregnant Uterus ◽  
T Cell Biology

CD8+ T cells are the most frequent T cell population in the immune cell compartment at the feto-maternal interface. Due to their cytotoxic potential, the presence of CD8+ T cells in the immune privileged pregnant uterus has raised considerable interest. Here, we review our current understanding of CD8+ T cell biology in the uterus of pregnant women and discuss this knowledge in relation to a recently published immune cell Atlas of human decidua. We describe how the expansion of CD8+ T cells with an effector memory phenotype often presenting markers of exhaustion is critical for a successful pregnancy, and host defense towards pathogens. Moreover, we review new evidence on the presence of long-lasting immunological memory to former pregnancies and discuss its impact on prospective pregnancy outcomes. The formation of fetal-specific memory CD8+ T cell subests in the uterus, in particular of tissue resident, and stem cell memory cells requires further investigation, but promises interesting results to come. Advancing the knowledge of CD8+ T cell biology in the pregnant uterus will be pivotal for understanding not only tissue-specific immune tolerance but also the etiology of complications during pregnancy, thus enabling preventive or therapeutic interventions in the future.

scholarly journals Longitudinal Changes in Cd4+, Cd8+ T Cell Phenotype and Activation Marker Expression Following Antiretroviral Therapy Initiation among Patients with Cryptococcal Meningitis

2019 ◽  
Vol 5 (3) ◽  
pp. 63
Author(s):  
Alice Bayiyana ◽  
Samuel Okurut ◽  
Rose Nabatanzi ◽  
Godfrey Zziwa ◽  
David R. Boulware ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Cell Surface ◽  
Cd8 T Cells ◽  
Cryptococcal Meningitis ◽  
Cd8 T Cell ◽  
Cd4 T Cell ◽  
Effector Memory ◽  
Memory Subset

Despite improvement in the prognosis of HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) patients on antiretroviral therapy (ART), cryptococcal meningitis (CM) still causes 10–15% mortality among HIV-infected patients. The immunological impact of ART on the CD4+ and CD8+ T cell repertoire during cryptococcal co-infection is unclear. We determined longitudinal phenotypic changes in T cell subsets among patients with CM after they initiated ART. We hypothesized that ART alters the clonotypic phenotype and structural composition of CD4+ and CD8+ T cells during CM co-infection. For this substudy, peripheral blood mononuclear cells (PBMC) were isolated at four time points from CM patients following ART initiation during the parent study (ClinicalTrials.gov number, NCT01075152). Phenotypic characterization of CD4+ and CD8+ T cells was done using T cell surface marker monoclonal antibodies by flow cytometry. There was variation in the expression of immunophenotypic markers defining central memory (CD27+CD45R0+), effector memory (CD45R0+CD27–), immune activation (CD38+ and Human Leucocyte Antigen DR (HLA-DR+), and exhaustion (Programmed cell death protein one (PD-1) in the CD4+ T cell subset. In comparison to the CD4+ T cell population, the CD8+ central memory subset declined gradually with minimal increase in the effector memory subset. Both CD4+ and CD8+ T cell immune exhaustion and activation markers remained elevated over 12 weeks. The relative surge and decline in the expression of T cell surface markers outlines a variation in the differentiation of CD4+ T cells during ART treatment during CM co-infection.

IL-8 responsiveness defines a subset of CD8 T cells poised to kill

Blood ◽  
2004 ◽  
Vol 104 (12) ◽  
pp. 3463-3471 ◽  
Author(s):  
Christoph Hess ◽  
Terry K. Means ◽  
Patrick Autissier ◽  
Tonia Woodberry ◽  
Marcus Altfeld ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chemokine Receptor ◽  
Cd8 T Cells ◽  
Molecular Mechanisms ◽  
Cell Subset ◽  
Cd8 T Cell ◽  
Effector Memory ◽  
Immune System Activation ◽  
Hiv 1

CD8 T cells play a key role in host defense against intracellular pathogens. Efficient migration of these cells into sites of infection is therefore intimately linked to their effector function. The molecular mechanisms that control CD8 T-cell trafficking into sites of infection and inflammation are not well understood, but the chemokine/chemokine receptor system is thought to orchestrate this process. Here we systematically examined the chemokine receptor profile expressed on human CD8 T cells. Surprisingly, we found that CXC chemokine receptor 1 (CXCR1), the predominant neutrophil chemokine receptor, defined a novel interleukin-8/CXC ligand 8 (IL-8/CXCL8)–responsive CD8 T-cell subset that was enriched in perforin, granzyme B, and interferon-γ (IFNγ), and had high cytotoxic potential. CXCR1 expression was down-regulated by antigen stimulation both in vitro and in vivo, suggesting antigen-dependent shaping of the migratory characteristics of CD8 T cells. On virus-specific CD8 T cells from persons with a history of Epstein-Barr virus (EBV) and influenza infection, CXCR1 expression was restricted to terminally differentiated effector memory cells. In HIV-1 infection, CXCR1-expressing HIV-1–specific CD8 T cells were present only in persons who were able to control HIV-1 replication during structured treatment interruptions. Thus, CXCR1 identifies a subset of CD8 T cells poised for immediate cytotoxicity and early recruitment into sites of innate immune system activation.

scholarly journals Mitochondrial Dysfunction Associates With Acute T Lymphocytopenia and Impaired Functionality in COVID-19 Patients

2022 ◽  
Vol 12 ◽  
Author(s):  
Yufei Mo ◽  
Kelvin Kai-Wang To ◽  
Runhong Zhou ◽  
Li Liu ◽  
Tianyu Cao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mitochondrial Dysfunction ◽  
Cd8 T Cells ◽  
Functional Impairment ◽  
Cell Loss ◽  
Cd8 T Cell ◽  
Underlying Mechanism ◽  
T Cell Subsets ◽  
Effector Memory

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in rapid T lymphocytopenia and functional impairment of T cells. The underlying mechanism, however, remains incompletely understood. In this study, we focused on characterizing the phenotype and kinetics of T-cell subsets with mitochondrial dysfunction (MD) by multicolor flow cytometry and investigating the association between MD and T-cell functionality. While 73.9% of study subjects displayed clinical lymphocytopenia upon hospital admission, a significant reduction of CD4 or CD8 T-cell frequency was found in all asymptomatic, symptomatic, and convalescent cases. CD4 and CD8 T cells with increased MD were found in both asymptomatic and symptomatic patients within the first week of symptom onset. Lower proportion of memory CD8 T cell with MD was found in severe patients than in mild ones at the stage of disease progression. Critically, the frequency of T cells with MD in symptomatic patients was preferentially associated with CD4 T-cell loss and CD8 T-cell hyperactivation, respectively. Patients bearing effector memory CD4 and CD8 T cells with the phenotype of high MD exhibited poorer T-cell responses upon either phorbol 12-myristate-13-acetate (PMA)/ionomycin or SARS-CoV-2 peptide stimulation than those with low MD. Our findings demonstrated an MD-associated mechanism underlying SARS-CoV-2-induced T lymphocytopenia and functional impairment during the acute phase of infection.

PD-1 up-regulation is correlated with HIV-specific memory CD8+ T-cell exhaustion in typical progressors but not in long-term nonprogressors

Blood ◽  
2007 ◽  
Vol 109 (11) ◽  
pp. 4671-4678 ◽  
Author(s):  
Ji-Yuan Zhang ◽  
Zheng Zhang ◽  
Xicheng Wang ◽  
Jun-Liang Fu ◽  
Jinxia Yao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Effector Memory ◽  
T Cell Exhaustion ◽  
Cell Exhaustion ◽  
Specific Memory ◽  
Memory Cd8 T Cell

Abstract The immunoreceptor PD-1 is significantly up-regulated on exhausted CD8+ T cells during chronic viral infections such as HIV-1. However, it remains unknown whether PD-1 expression on CD8+ T cells differs between typical progressors (TPs) and long-term nonprogressors (LTNPs). In this report, we examined PD-1 expression on HIV-specific CD8+ T cells from 63 adults with chronic HIV infection. We found that LTNPs exhibited functional HIV-specific memory CD8+ T cells with markedly lower PD-1 expression. TPs, in contrast, showed significantly up-regulated PD-1 expression that was closely correlated with a reduction in CD4 T-cell number and an elevation in plasma viral load. Importantly, PD-1 up-regulation was also associated with reduced perforin and IFN-γ production, as well as decreased HIV-specific effector memory CD8+ T-cell proliferation in TPs but not LTNPs. Blocking PD-1/PD-L1 interactions efficiently restored HIV-specific CD8+ T-cell effector function and proliferation. Taken together, these findings confirm the hypothesis that high PD-1 up-regulation mediates HIV-specific CD8+ T-cell exhaustion. Blocking the PD-1/PD-L1 pathway may represent a new therapeutic option for this disease and provide more insight into immune pathogenesis in LTNPs.

scholarly journals The differential production of cytokines by human Langerhans cells and dermal CD14+ DCs controls CTL priming

Blood ◽  
2012 ◽  
Vol 119 (24) ◽  
pp. 5742-5749 ◽  
Author(s):  
Jacques Banchereau ◽  
LuAnn Thompson-Snipes ◽  
Sandra Zurawski ◽  
Jean-Philippe Blanck ◽  
Yanying Cao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Langerhans Cells ◽  
Expression Profiles ◽  
Cd8 T Cell ◽  
Inhibitory Effect ◽  
Effector Memory ◽  
Functional Difference ◽  
T Cell Priming

Abstract We recently reported that human epidermal Langerhans cells (LCs) are more efficient than dermal CD14+ DCs at priming naive CD8+ T cells into potent CTLs. We hypothesized that distinctive dendritic cell (DC) cytokine expression profiles (ie, IL-15 produced by LCs and IL-10 expressed by dermal CD14+ DCs) might explain the observed functional difference. Blocking IL-15 during CD8+ T-cell priming reduced T-cell proliferation by ∼ 50%. These IL-15–deprived CD8+ T cells did not acquire the phenotype of effector memory cells. They secreted less IL-2 and IFN-γ and expressed only low amounts of CD107a, granzymes and perforin, and reduced levels of the antiapoptotic protein Bcl-2. Confocal microscopy analysis showed that IL-15 is localized at the immunologic synapse of LCs and naive CD8+ T cells. Conversely, blocking IL-10 during cocultures of dermal CD14+ DCs and naive CD8+ T cells enhanced the generation of effector CTLs, whereas addition of IL-10 to cultures of LCs and naive CD8+ T cells inhibited their induction. TGF-β1 that is transcribed by dermal CD14+ DCs further enhanced the inhibitory effect of IL-10. Thus, the respective production of IL-15 and IL-10 explains the contrasting effects of LCs and dermal CD14+ DCs on CD8+ T-cell priming.

Autoproliferation Contributes to Clonal Expansion and Changes In Cellular Topography In T Cell Large Granular Lymphocyte (LGL) Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1373-1373
Author(s):  
JianXiang Zou ◽  
Jeffrey S Painter ◽  
Fanqi Bai ◽  
Lubomir Sokol ◽  
Thomas P. Loughran ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
Cd8 T Cell ◽  
Effector Memory ◽  
Ki67 Expression ◽  
Terminal Effector ◽  
Lgl Leukemia

Abstract Abstract 1373 Introduction: LGL leukemia is associated with cytopenias and expansion of clonally-derived mature cytotoxic CD8+ lymphocytes. The etiology of LGL leukemia is currently unknown, however, T cell activation, loss of lymph node homing receptor L-selectin (CD62L), and increased accumulation of T cells in the bone marrow may lead to suppressed blood cell production. The broad resistance to Fas (CD95) apoptotic signals has lead to the hypothesis that amplification of clonal cells occurs through apoptosis resistance. However, the proliferative history has not been carefully studied. To define possible mechanism of LGL leukemia expansion, T cell phenotype, proliferative history, and functional-related surface marker expression were analyzed. Methods: Peripheral blood mononuclear cells (PBMCs) were obtained from 16 LGL leukemia patients that met diagnostic criteria based on the presence of clonal aβ T cells and >300 cells/ml CD3+/CD57+ T cells in the peripheral blood. Samples were obtained from 10 age-matched healthy individuals from the Southwest Florida Blood Services for comparisons. Multi-analyte flow cytometry was conducted for expression of CD3, CD4/8, CD45RA, CD62L, CD27, CD28, CD25, CD127, IL15Ra, IL21a, CCR7 (all antibodies from BD Biosciences). The proliferative index was determined by Ki67 expression in fixed and permeabilized cells (BD Biosciences) and the proliferative history in vivo was assessed by T-cell-receptor excision circle (TREC) measurement using real-time quantitative PCR (qRT-PCR) in sorted CD4+ and CD8+ T cells. TRECs are episomal fragments generated during TCR gene rearrangements that fail to transfer to daughter cells and thus diminish with each population doubling that reflects the in vivo proliferative history. Results: Compared to healthy controls, significantly fewer CD8+ naïve cells (CD45RA+/CD62L+, 8.4 ± 10.8 vs 24.48 ± 11.99, p=0.003) and higher CD8+ terminal effector memory (TEM) T cells (CD45RA+/CD62L-, 67.74 ± 28.75 vs 39.33 ± 11.32, p=0.007) were observed in the peripheral blood. In contrast, the percentage of CD4+ naïve and memory cells (naïve, central memory, effector memory, and terminal effector memory based on CD45RA and CD62L expression) was similar in patients as compared to controls. The expression of CD27 (31.32 ± 34.64 vs 71.73 ± 20.63, p=0.003) and CD28 (31.38 ± 31.91 vs 70.02 ± 22.93, p=0.002) were lower in CD8+ T cell from patients with LGL leukemia and this reduction predominated within the TEM population (17.63±24.5 vs 70.98±22.5 for CD27, p<0.0001 and 13±20.5 vs 69.43± 21.59 for CD28, p<0.0001). Loss of these markers is consistent with prior antigen activation. There was no difference in CD25 (IL2Ra, p=0.2) expression on CD4+ or CD8+ T cells, but CD127 (IL7Ra, p=0.001), IL15Ra, and IL21Ra (p=0.15) were overexpressed in TEM CD8+ T cell in patients vs controls. All of these cytokine receptors belong to the IL2Rβg-common cytokine receptor superfamily that mediates homeostatic proliferation. In CD8+ T cells in patients, the IL-21Ra was also overexpressed in naïve, central and effector memory T cells. The topography of the expanded CD8+ T cell population was therefore consistent with overexpression of activation markers and proliferation-associated cytokine receptors. Therefore, we next analyzed Ki67 expression and TREC DNA copy number to quantify actively dividing cells and determine the proliferative history, respectively. We found that LGL leukemia patients have more actively dividing CD8+ TEM T cells compared to controls (3.2 ± 3.12 in patients vs 0.44 ± 0.44 in controls, p=0.001). Moreover, the TREC copy number in CD8+ T cells was statistically higher in healthy individuals after adjusting for age (177.54 ± 232 in patients vs 1015 ± 951 in controls, p=0.019). These results show that CD8+ cells in the peripheral compartment have undergone more population doublings in vivo compared to healthy donors. In contrast, the TREC copies in CD4+ T-cells were similar between LGL patients and controls (534.4 ± 644 in patients vs 348.78 ± 248.16 in controls, p>0.05) demonstrating selective cellular proliferation within the CD8 compartment. Conclusions: CD8+ T- cells are undergoing robust cellular activation, contraction in repertoire diversity, and enhanced endogenous proliferation in patients with LGL leukemia. Collectively, these results suggest that clonal expansion is at least partially mediated through autoproliferation in T-LGL leukemia. Disclosures: No relevant conflicts of interest to declare.

TNFR2 Is Expressed Preferentially By Late Differentiated CD8 T-Cells and Can be Triggered By TNFR2-Specific Ligand to Induce Cell Death of Recently Activated Antigen-Specific T Cells: A Possible Role of TNFR2 in T-Cell Deflation

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4352-4352
Author(s):  
Mohammad Raeiszadeh ◽  
Matthew Verney ◽  
Charles Craddock ◽  
Harald Wajant ◽  
Paul Moss ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Receptor Expression ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Cell Transplant ◽  
Gamma Chain ◽  
Transplant Patients

Abstract Recent evidence suggests that Tumor Necrosis Factor (TNF) can selectively kill antigen-specific autoreactive CD8+ T-cells through engagement with TNF Receptor 2 (TNFR2) (1). Within the immune system, TNFR2 expression is restricted to subsets of T-cells, a profile which is in marked contrast to the ubiquitous pattern of expression of TNFR1. However, the spectrum and physiological significance of TNFR2 expression by CD8+ T-cell subpopulations is unknown. In this study we analysed the expression of TNFR2 by CD8 T-cell subsets isolated from normal healthy donors by flow cytometry. In addition, in order to understand the physiological significance of TNFR2 expression on recently activated T cells, we further studied expression on CMV-specific CD8 T-cells which expanded in stem cell transplant patients in response to episodes of CMV reactivation. The expression of TNFR2 was compared to that of other common gamma chain receptors including IL2R and IL7R, and to the expression of a receptor for inflammatory cytokine IL6. TNFR2 expression was found to increase during differentiation of CD8+ T cells. In particular, TNFR2 expression was seen on 6.5% of naïve, 14.6% of central memory, 37.9% of effector memory and 45.2% of CD45RA-revertant effector memory (TEMRA) CD8+ T cells. In contrast, common gamma chain cytokine receptor expression was skewed towards less differentiated T-cell subsets. For example, IL-7R was expressed by 63% of central memory populations but only 18.4% of the TEMRA subset. Comparable expression of IL2R was 12.1% on TCM and 2% on TEMRA. Of interest, IL-6 receptor expression was predominantly expressed by naïve CD8 T-cells (69.5%). In support of these results, we went on to show that expression of TNFR2 was inducible on primary T cells following activation with anti-CD3 and IL-2 in vitro. Healthy CMV seropositive donors had a larger median number of CD8+ T cells expressing TNFR2 (53%) in comparison to CMV seronegative donors (15%), (p<0.0001), consistent with the known accumulation of differentiated T-cells within CMV seropositive individuals.The expression of TNFR2 was then examined on CMV-specific CD8 T-cells which were undergoing acute expansion in response to viremia in six haemopoietic stem cell transplant patients. The expansion of CMV-specific CD8 T-cells was accompanied by an increase in the intensity of TNFR2 expression which later decreased during the retraction of antigen-specific T-cells during resolution of viremia. In order to explore the functional significance of TNFR2 expression, T-cells isolated from healthy donors were treated with recombinant TNFR2-specific ligand. This induced cell loss ranging from 13% to 60% of all CD8 T-cells in relation to untreated control cells, with selective depletion of the TNFR2+ population. A similar proportion of CMV-specific T-cells from transplant patients were eliminated by ex vivo stimulation of TNFR2. In conclusion our work shows that TNFR2 expression increases during differentiation of CD8+ T cells. In addition, we were able to utilize virus-specific T cells from SCT patients to show that expression is increased during the acute response to stimulation with antigen. We also provide evidence that TNFR2 activation can lead to the partial elimination of antigen-specific CMV-specific T-cells and it may thus play an important role in the ‘deflation’ of a pathogen-specific T-cell immune response following resolution of infection. These data suggest that TNFR2 expression may act as a ligand to signal activation-induced cell death in late differentiated populations of CD8+ T cells. Further investigations are required to assess the molecular pathways of TNFR2 signalling that are activated following receptor ligation in vivoand whether or not these are disrupted in disorders associated with chronic CD8+ T cell lymphproliferation. (1) L. Ban et al, PNAS 2008, 105: 3644 Disclosures No relevant conflicts of interest to declare.

scholarly journals Naïve CD8 T cell IFNγ responses to a vacuolar antigen are regulated by an inflammasome-independent NLRP3 pathway and Toxoplasma gondii ROP5

2020 ◽  
Author(s):  
Angel K. Kongsomboonvech ◽  
Felipe Rodriguez ◽  
Anh L. Diep ◽  
Brandon M. Justice ◽  
Brayan E. Castallanos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Toxoplasma Gondii ◽  
Cd8 T Cells ◽  
Immune Cell ◽  
Cd8 T Cell ◽  
Inflammasome Activation ◽  
Phenotypic Variance ◽  
Dependent Manner ◽  
Presentation Pathway

ABSTRACTHost resistance to Toxoplasma gondii relies on CD8 T cell IFNγ responses, which if modulated by the host or parasite could influence chronic infection and parasite transmission between hosts. Since host-parasite interactions that govern this response are not fully elucidated, we investigated requirements for eliciting naïve CD8 T cell IFNγ responses to a vacuolar resident antigen of T. gondii, TGD057. Naïve TGD057 antigen-specific CD8 T cells (T57) were isolated from transnuclear mice and responded to parasite-infected bone marrow-derived macrophages (BMDMs) in an antigen-dependent manner, first by producing IL-2 and then IFNγ. T57 IFNγ responses to TGD057 were independent of the parasite’s protein export machinery ASP5 and MYR1. Instead, host immunity pathways downstream of the regulatory Immunity-Related GTPases (IRG), including partial dependence on Guanylate-Binding Proteins, are required. Multiple T. gondii ROP5 isoforms and allele types, including ‘avirulent’ ROP5A from clade A and D parasite strains, were able to suppress CD8 T cell IFNγ responses to parasite-infected BMDMs. Phenotypic variance between clades B, C, D, F, and A strains suggest T57 IFNγ differentiation occurs independently of parasite virulence or any known IRG-ROP5 interaction. Consistent with this, removal of ROP5 is not enough to elicit maximal CD8 T cell IFNγ production to parasite-infected cells. Instead, macrophage expression of the pathogen sensors, NLRP3 and to a large extent NLRP1, were absolute requirements. Other members of the conventional inflammasome cascade are only partially required, as revealed by decreased but not abrogated T57 IFNγ responses to parasite-infected ASC, caspase-1/11, and gasdermin D deficient cells. Moreover, IFNγ production was only partially reduced in the absence of IL-12, IL-18 or IL-1R signaling. In summary, T. gondii effectors and host machinery that modulate parasitophorous vacuolar membranes, as well as NLR-dependent but inflammasome-independent pathways, determine the full commitment of CD8 T cells IFNγ responses to a vacuolar antigen.AUTHOR SUMMARYParasites are excellent “students” of our immune system as they can deflect, antagonize and confuse the immune response making it difficult to vaccinate against these pathogens. In this report, we analyzed how a widespread parasite of mammals, Toxoplasma gondii, manipulates an immune cell needed for immunity to many intracellular pathogens, the CD8 T cell. Host pathways that govern CD8 T cell production of the immune protective cytokine, IFNγ, were also explored. We hypothesized the secreted Toxoplasma virulence factor, ROP5, work to inhibit the MHC 1 antigen presentation pathway therefore making it difficult for CD8 T cells to see T. gondii antigens sequestered inside a parasitophorous vacuole. However, manipulation through T. gondii ROP5 does not fully explain how CD8 T cells commit to making IFNγ in response to infection. Importantly, CD8 T cell IFNγ responses to T. gondii require the pathogen sensor NLRP3 to be expressed in the infected cell. Other proteins associated with NLRP3 activation, including members of the conventional inflammasome activation cascade pathway, are only partially involved. Our results identify a novel pathway by which NLRP3 regulates T cell function and underscore the need for inflammasome-activating adjuvants in vaccines aimed at inducing CD8 T cell IFNγ responses to parasites.

IL-15 Plays a Critical Role in CD8+ T-Cell Recovery after Allogeneic Transplantation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1414-1414
Author(s):  
Frances T. Hakim ◽  
Kenton Allen ◽  
Jesse M. Carson ◽  
Michael Boyiadzis ◽  
Sarfraz A. Memon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Receptor Expression ◽  
Brdu Incorporation ◽  
Effector Memory ◽  
Cell Populations ◽  
Cell Recovery ◽  
Post Transplant

Abstract In severely lymphopenic hosts, CD4+ and CD8+ T cell populations increase rapidly through peripheral homeostatic expansion, a process in which IL-7 has been found to play a key role. Because of the marked differences in the kinetics of CD4+ and CD8+ T cell repopulation following hematopoietic stem cell transplants (HSCT), we have investigated the roles of additional cytokines in early repopulation. Interleukin-15 (IL-15) supports the proliferation, terminal differentiation, and survival of NK, NKT and memory CD8+ T-cell populations, all of which increase disproportionately in the early transplant period. We therefore investigated the role of IL-15 in post-transplant CD8+ T cell recovery by assessing plasma IL-15 levels, IL-15 receptor expression and IL-15-induced proliferation by BrdU incorporation. In patients undergoing non-myeloablative HLA-matched allogeneic HSCT for hematological and non-hematological malignancies, IL-15 levels in the plasma increased concurrent with the loss of lymphocytes during each cycle of inductive chemotherapy, and peaked at a 50-fold increase over pretreatment levels at day of transplant, a time when CD8+ T cell levels were usually less than 1 cell/μL. Plasma IL-15 levels fell rapidly in the first two weeks, during the rapid recovery of NK and CD8+ T cell populations, returning to pretransplant levels by 1–2 months. Overall, during the cytoreductive transplant and for the first year post transplant, the IL-15 levels were inversely proportional to the level of CD8 T cells (P &lt; 0.0001; r = −0.73). In the first weeks after transplant, CD8+T-cells expressed elevated levels of CD122, but had little or no expression of CD25, the IL-2Ralpha chain. Levels of CD122 remained elevated for several months, while expression of CD127, IL-7Ralpha, was reduced. In vitro BrdU incorporation assays demonstrated that CD8+ T-cells from both normal donors and transplant recipients responded primarily to IL-15, not IL-7 or IL-2. CD4+ T cells, in contrast, responded primarily to IL-7. A higher proportion of CD28+CD45RA− memory and CD28−CD45RA+/− effector-memory CD8+ T-cells incorporated BrdU than did naive CD28+CD45RA+ CD8+ T cells. Finally, IL-15, not IL-2 or IL-7, was found to maintain survival and support expansion in culture of the CD28−CD57+ terminal effector cells that dominate post transplant CD8+ T-cells populations. These data, describing an inverse relationship between the levels of free plasma IL-15 and CD8+ T cells, elevated expression of IL-15 receptor chain and strong responsiveness of post transplant CD8+ T cells to IL-15, suggest that IL-15 serves as a critical homeostatic cytokine post transplant, supporting the initial rapid generation CD8+ T cells and maintaining elevated levels of memory/effector CD8+ T-cell populations in the post transplant period.

A Comparison of Human CMVpp65-Specific Central Memory and Effector Memory CD8 T-Cells When Stimulated in-Vivo with IL-2 or IL-15/IL-15Rα Complex in a Murine Xenograft Model of Adoptive Cell Therapy

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4805-4805
Author(s):  
Tzu-Yun Kuo ◽  
Aisha Hasan ◽  
Richard J O'Reilly
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Adoptive Immunotherapy ◽  
Memory T Cells ◽  
Cd8 T Cell ◽  
Central Memory ◽  
Effector Memory ◽  
Cell Clones

Abstract Initial clinical trials of adoptive immunotherapy have shown that the efficacy of adoptively transferred T-cells in man is often limited by the failure of cultured T cells, particularly cloned CD8 T cells, to persist in vivo. These studies demonstrated that the transferred T cells induced only transient responses and that persistence of the transferred T-cell clonotypes correlated with disease regression. A previous study suggested that CMV virus-specific CD8 T cell clones derived from central memory T cells (TCM), but not effector memory T cells (TEM), persisted long-term in non-human primates. On the other hand, another study comparing TCM and TEM derived SIV virus specific CD8 T-cell clones that were adoptively transferred in non-human primates demonstrated limited persistence of both TCM and TEM derived transferred T cells, and failed to show any difference between the two cell types. Because of these conflicting data, we have reexamed the persistence of adoptively transferred viral antigen specific T-cells derived from TCM and TEM population. Accordingly, we developed a NOG mouse model for studying the ability of human CMVpp65-specific T cells derived from central memory and effector memory populations to migrate to and accumulate in human tumor xenografts expressing CMVpp65, to alter the growth of these tumors and to persist in the tumors. This model also allows us to test immunomodulating agents and their ability to enhance targeted T-cell accumulations, antitumor activity and persistence. We analyzed CMVpp65-specific CD8 T cells derived from TCM and TEM precursors in vitro and in vivo. To tract the T-cells in vivo, we transduced membrane-bound Gaussia luciferase into TCM and TEM populations and monitored T cell trafficking by in vivo bioluminescence. Contrary to expectation, our results initially showed no differences between TCM and TEM derived CMVpp65-specific T-cell in mice co-treated with IL-2 in the time to accumulation, ultimate level of accumulation, degree of CMVpp65+ tumor regression or T-cell persistence. However, in mice cotreated with IL-15/IL-15Rα complex, both TCM and TEM exhibited more sustained engraftment and more prolonged accumulation in both the targeted tumor and in the marrow. In mice treated with IL-15/IL-15Rα, TCM and TEM derived T cells showed a similar effector memory phenotype and a similar level of regression of tumor growth. Thus, adoptive transfer of CMVpp65 specific TCM or TEM when combined with IL-15/IL-15Rα complex may support better persistence of antigen-specific T-cells following adoptive immunotherapy. Studies comparing IL-15/IL-15Rα complex with IL-15 alone are in progress. Disclosures No relevant conflicts of interest to declare.

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