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 < 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.

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.

Recovery of CMV-Specific T Cells Following Alternative Donor Allogeneic Transplant with Post-Transplant Cyclophosphamide

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5462-5462
Author(s):  
Ayman Saad ◽  
Samantha B Langford ◽  
Shin Mineishi ◽  
Lawrence S. Lamb
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Recovery ◽  
Post Transplant ◽  
Increased Risk ◽  
Cmv Reactivation

Abstract Background: Post-transplant cyclophosphamide (PTCy) is increasingly used for GVHD prophylaxis after allogeneic hematopoietic stem cell transplantation (HCT) using alternative donors. However, immune reconstitution can be delayed posing an increased risk for CMV reactivation. We evaluated the outcomes of patients who received HCT-apheresis products comparing the impact of PTCy on lymphocyte recovery, CMV reactivation and CMV-specific CD8+ T cell recovery following haplo-identical (HAPLO), matched unrelated donor (MUD), and mismatched unrelated donor (mMUD) grafts vs. with conventional matched related donor (MRD) graft recipients. Methods: We examined 26 patients (median age, 49 years; range, 20-72 years) with advanced hematologic malignancies; n=5 (HAPLO); 6 (MRD); 15 (MUD). All patients received myeloablative conditioning regimens that was either busulfan- or total body irradiation (TBI)-based. PTCy (50 mg/kg/day) was administered on days +3 and +4 following HAPLO and on day +3 following MUD/mMUD transplant. Peripheral blood lymphocyte reconstitution and frequency of circulating CMV-directed CD8+ T cells was assessed (day ± 10 days) on post-transplant days +30, +60, and +90. Circulating anti-CMV T cell frequency was assessed using a phycoerythrin-tagged MHC dextramer against HLA-specific CMV pp65, IE-1, or pp50 peptides (Immudex; Copenhagen, DK) in combination with Tru-Count¨ tubes and fluorescent-labeled monoclonal antibodies against CD3, CD8, CD4, CD16/56, and CD19 (BD Biosciences; San Jose, CA). Anti-CMV CD8+ T cell immunity was defined as a CMV-dextramer (CMV/DEX) positive count of ≥7cells/ml. CMV reactivation was defined as a serologic titer of >500IU/mL. All patients with CMV reactivation received ganciclovir therapy until CMV titer became negative. Results: Day +30 total T cell recovery was significantly faster in MRD than CY-treated recipients (p=0.015) due principally to more robust CD8+ T cell recovery. CD4 T cell recovery remained below normal range in all groups through day +100. NK cells recovered to normal numbers at day +28 in all groups. Neither PTCy nor donor source significantly impacted the percentage of patients that recovered anti-CMV CD8+ T cells at each time interval (p = 0.8232). Excluding donors (D) and recipients (R) that were both negative, CMV/DEX+ T cells recovery was >7/mL in 4/5 MRD, 7/14 MUD, and 3/5 HAPLO by day +100. Among MRD recipients either D+ or R+ (n=5), 2 patients showed CMV reactivation within 40 days of transplant that was associated with <7 CMV/DEX+ T cells on day +30. Subsequent high (>90/mL) CMV/DEX T cell response in one patient shortened the duration of viremia to 10 days (vs. 16 days with poor responder) and 3 patients showed no CMV reactivation and a high CMV/DEX+ T cell response by day +60. For MUD CMV D+ and/or R+ recipients (n=14), 3 showed CMV reactivation within 50 days of transplant. All 3 patients had suboptimal CMV/DEX T cell response on day +30. Robust CMV/DEX+ T cell response on day +60 predicted shorter duration of viremia (20 days vs. average of 32 days). For HAPLO CMV D+ and/or R+ (n=5) recipients, 4 experienced CMV reactivation within 50 days of transplant. All patients had a <7 CMV/DEX+ T cells/mL +30. Robust CMV/DEX+ T cell response by day +60 was associated with shorter duration of viremia (range 7-21 days), while one patient with <7/mL CMV/DEX+ T cells had continued CMV viremia for 36 days. Conclusion: In this preliminary analysis, neither PTCy nor donor source significantly impacted the percentage of patients that recovered anti-CMV CD8+ T cells at each time interval. A weak CMV/DEX+ response (<7 cells/mL) on day +30 was consistent with increased risk of CMV reactivation (viremia) in all groups. A CMV/DEX+ T cell count ≥7 cells/mL was not immediately protective against CMV reactivation, but higher counts were associated with a shortened duration of viremia while on antiviral therapy. Conversely, subnormal counts were associated with a longer duration of viremia. This interim analysis suggests that CMV/DEX+ T cell enumeration is a useful biologic correlate for determining clinical response to antiviral therapy, and that donor-derived CMV specific T cell immunity is not further compromised with following PTCy in alternative donor HCT. Disclosures No relevant conflicts of interest to declare.

High Avidity Leukemia-Associated Antigen-Specific CD8+ T Cells Preferentially Localize to the Bone Marrow in Patients with Myeloid Malignancies.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2763-2763
Author(s):  
J. Jopseph Melenhorst ◽  
Phillip Scheinberg ◽  
Pratip K. Chattopadhyay ◽  
Emma Gostick ◽  
Mario Roederer ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Heavy Chain ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Effector Memory ◽  
Cell Populations ◽  
High Avidity ◽  
Myeloid Malignancies

Abstract Both acute and chronic myeloid leukemias (AML and CML) and myelodysplastic syndromes (MDS) over-express and present self-antigens such as the HLA-A*0201-restricted proteinase 3 (PR1) and Wilm’s tumor-1 (WT1) epitopes, making these leukemia-associated antigens selectively amenable to immunotherapeutic intervention. Here, we examined the antigen avidity properties of circulating and bone marrow-resident CD8+ T cells specific for PR1 and WT1 in patients with AML (n=11), CML (n=10) and MDS (n=3). A total of 19 bone marrow (BM) samples and 27 peripheral blood (PB) samples were studied both prior to and following stem cell transplantation (SCT). Cognate HLA-A*0201 tetramers with identical TCR docking platforms were produced using three distinct monomeric HLA-A*0201 complexes with differential coreceptor binding properties to dissect the avidity of antigen binding directly ex vivo: “CD8-null” tetramers, which contain a compound D227K/T228A mutation in the a3 domain of the heavy chain that abrogates CD8 binding; wildtype tetramers; and, “CD8-enhanced” tetramers, which contain a Q115E mutation in the a2 domain of the heavy chain that moderately increases CD8 binding. We have shown previously that CD8-null tetramers engage only high avidity antigen-specific CD8+ T cells; in contrast, CD8-enhanced tetramers can engage populations of antigen-specific CD8+ T cells with low avidities that fall below the threshold for detection with wildtype tetramers. Using these reagents, we developed a polychromatic flow cytometric panel that enabled the simultaneous assessment of phenotype, function and avidity within antigen-specific CD8+ T cell populations. Either PR1- and/or WT1-specific CD8+ T cells were identified in 12/19 BM samples and 6/27 PB samples. Notably, one of the pre-SCT samples contained only low avidity leukemia-associated antigen-specific CD8+ T cells; in contrast, all of the specific populations identified in the post-SCT samples engaged their cognate antigen with high avidity. In 5/7 patients, analysis of paired BM/PB samples revealed the presence of high avidity PR1- and/or WT1-specific CD8+ T cells confined almost exclusively to the BM. Phenotypic analysis demonstrated a mixture of central and effector memory cells in all cases, thereby confirming that these PR1- and WT1-specific CD8+ T cell populations were antigen-experienced. Thus, high avidity CD8+ T cells specific for leukemia-associated antigens are present in vivo and preferentially localize to BM in myeloid malignancies.

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.

Altered Naive and Memory T Cell Homeostasis and Immunosenescence Characterize Younger Patients with Immunosuppressive-Responsive Myelodysplastic Syndrome

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3647-3647
Author(s):  
JianXiang Zou ◽  
Dana E Rollison ◽  
David Boulware ◽  
Elaine M. Sloand ◽  
Loretta Pfannes ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immunosuppressive Therapy ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Effector Memory ◽  
Cell Populations ◽  
T Cell Homeostasis ◽  
Cell Homeostasis ◽  
Younger Patients

Abstract BACKGROUND: A subset of patients with Myelodysplastic Syndrome (MDS) responds well to immunosuppressive therapy (IST) and the only validated predictor of response is age, with younger patients faring much better than older patients. Hematologic improvement on immunosuppressive therapy is associated with a survival benefit with response rates ranging from 15% to 50%, clearly comparable or better than results with other existing therapies in MDS. Despite progress in the basic understanding of immune pathobiology of MDS and a clear therapeutic value, including improved long-term survival, IST including anti-thymocyte globulin (ATG) and/or cyclosporine A (CyA) is rarely offered to MDS patients in the U.S. due to uncertain criteria for selection of patients and potential toxicities. In addition, there is an underlying concern that inappropriate use of immunosuppressive therapy may negatively impact risk for leukemia progression, which occurs in 30–40% of MDS cases. The long-term goal of this study is to identify an immune signature that has postive predictive power for IST responsiveness. METHODS: To determine the effect of age on T-cell homeostasis and function and IST response, we performed a study of 54 MDS patients compared to 37 healthy controls. In a pilot study, T cell abnormalities associated with response to equine anti-lymphocyte globulin (eATG, lymphoglobulin, Pfizer, Inc) and/or CyA was studied in 12 younger MDS patients composed of 6 responders and 6 non-responders. RESULTS: CD4+ T-cells are normally present in the peripheral blood lymphocyte pool at 2 to 4 times greater than that of CD8+ T-cells, and diminished CD4:CD8 ratio has been previously shown to correlate with poor survival outcome in MDS. Similar to previous reports, we found that the age-adjusted CD4:CD8 ratio was reduced in MDS patients compared to healthy controls (p-value <0.0001) Interestingly, our analysis revealed that inadequate CD4+ rather than expansion of CD8+ T-cells was associated with a lower ratio in this group of MDS patients that included both lower and higher risk MDS patients defined by the International Prognostic Scoring System (IPSS). Analysis of the percentage of T-cells with naïve and memory phenoytpes using CD45RA and CD62L display, demonstrated positive correlations between age and both % CD62L positive naïve cells and central memory CD4+ T-cells (naïve: slope=0.39, p=0.12; central memory: slope=1.26, p=0.005). Furthermore, the proportions of CD62L- CD4+ T-cell populations, including effector memory and terminal effector memory T-cells, were greater in younger MDS patients (slope=−0.82, p=0.08 and slope=−0.83, p=0.015, respectively) suggesting a possible relationship to IST responsiveness. Specific characteristics associated with response to eATG in the pilot study of 12 younger patients included altered distribution of T cell populations (i.e., lower CD4/CD8 ratio, p<0.001) and higher constitutive proliferative index of the T cell populations (p=0.03 CD4+ and p=0.02 CD8+ T-cells, respectively). We also found that hematological response was associated with blockade of homeostatic proliferation of T cells associated with reconstitution of the naïve T cell pool. Reduction in CD4+ T-cells and expansion of autoreactive CD8+ T-cells suggests that apoptotic conditions may drive the expansion of cells through homeostatic cytokines such as IL-7, IL-15, and/or IL-21, which are all cytokines of the IL-2Rγc family that control homeostatic proliferation. Comparisons of the IL-7Ra, IL-15Ra, IL-2Ra, and IL-21Ra subunit demonstrated overexpression of IL-21Ra in patients 35.4% ± 3.4 in CD4+ T-cells and 31.8% ± 4.3 in CD8+ T-cells compared to healthy donors 0.9% ± 0.5 and 0.5% ± 0.5 (p<0.0001). CONCLUSIONS: Association between the T-cell abnormalities reported in this study and response to IST strongly suggests that aberrant T-cell homeostasis may represent a critical determinant of autoimmunity in MDS that may have positive predictive power for response to IST.

Universal CD137 Expression upon Activation Allows Efficient Isolation of a Broad Repertoire of Virus-Specific CD8+ and CD4+ T Cells for Adoptive Immunotherapy.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2222-2222
Author(s):  
Maarten L. Zandvliet ◽  
J.H. Frederik Falkenburg ◽  
Inge Jedema ◽  
Roelof Willemze ◽  
Henk-Jan Guchelaar ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cd8 T Cell ◽  
Cell Populations ◽  
T Cell Lines ◽  
Kinetics Of ◽  
Ifng Production

Abstract Reactivation of adenovirus (ADV), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) can cause serious morbidity and mortality during the prolonged period of immune deficiency following allogeneic stem cell transplantation. It has been shown that adoptive transfer of donor-derived virus-specific T cells can be a successful strategy to control viral reactivation. To provide safe and effective anti-viral immunotherapy, we aimed to generate combined CD8+ and CD4+ T cell lines with high specificity for a broad range of viral epitopes. Isolation by the IFNg capture assay of virus-specific T cells that produce IFNg upon activation allows the generation of highly specific T cell lines without the need for extensive culture. However, it has been recently shown that specific upregulation of the co-stimulatory molecule CD137 upon antigen-specific activation of CD8+ and CD4+ T cells can also be used for isolation. We therefore analyzed IFNg production and CD137 expression by CD8+ and CD4+ T cells upon incubation of peripheral blood mononuclear cells (PBMC) from seropositive donors with peptides corresponding to 17 defined MHC class I restricted minimal epitopes from 10 different ADV, CMV, EBV and influenza (FLU) proteins, and 15-mer or 30-mer peptides containing MHC class II restricted epitopes from CMV pp65 or ADV hexon. Using tetramer and intracellular IFNg staining we first determined the fraction of CD8+ T cells that produced IFNg upon activation with the minimal epitopes. Specific IFNg production was observed for 58–100% of tetramer+ CD8+ T cells specific for CMV pp65 (n=6), and 83% for FLU (n=1), but only 18–58% for CMV pp50 (n=3) or IE-1 (n=3), 4–91% for EBV latent (n=3) and lytic (n=3) epitopes, and 41–63% for ADV hexon (n=2). In contrast to the variation in the fraction of IFNg-producing cells, we observed homogeneous upregulation of CD137 by the virus-specific tetramer+ T cell populations upon activation. In 2 cases where no CD137 expression by tetramer+ T cells could be detected, no IFNg production was observed either. These data suggest that the majority of CD8+ T cells specific for CMV pp65 or FLU can be isolated on basis of IFNg production, but only part of CD8+ T cell populations specific for other viral proteins, while complete virus-specific CD8+ T cell populations may be isolated on basis of CD137 expression. Activation of CD4+ T cells specific for CMV pp65 or ADV hexon with 15-mer or 30-mer peptides induced both specific IFNg production and CD137 expression. To investigate whether multiple virus-specific T cell populations could be isolated simultaneously, we next determined the kinetics of IFNg production after activation with defined MHC class I epitopes or peptides containing MHC class II epitopes. CMV- and EBV-specific CD8+ T cells and CMV-specific CD4+ T cells showed a rapid induction of IFNg production, which peaked after 4 hours and decreased thereafter. In contrast, ADV- and FLU-specific CD8+ T cells and ADV-specific CD4+ T cells, predominantly having a more early differentiation phenotype (CD27+CD28+) compared to CMV- and EBV-specific T cells, showed peak IFNg production after 8 hours that continued for more than 48 hours. This difference in phenotype and IFNg kinetics may suggest that the persistent and frequent presentation of CMV and EBV epitopes in vivo, in contrast to an intermittent exposure to ADV and FLU epitopes, drives differentiation and shapes the kinetics of the IFNg response of specific T cells. Kinetic analysis of CD137 expression showed uniform upregulation by virus-specific CD8+ T cell populations from day 1 to day 4 after activation, which peaked at day 2, suggesting that this may be the optimal time point for CD137-based isolation. In a limited number of experiments, virus-specific CD8+ and CD4+ T cells could be isolated based on CD137 expression within the same timeframe. These data indicate that virus-specific T cell populations can be more efficiently isolated at one time point on basis of CD137 expression than on basis of IFNg production, due to differences in IFNg kinetics. In conclusion, this study shows that T cell lines generated by CD137 isolation may comprise a significant number of virus-specific T cells which do not produce IFNg, but may have other effector functions. Furthermore, CD137-based enrichment may be more robust and allows the efficient simultaneous isolation of multiple virus-specific T cell populations due to uniform kinetics of CD137 expression.

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