Bim/Bcl-2 balance is critical for maintaining naive and memory T cell homeostasis

We examined the role of the antiapoptotic molecule Bcl-2 in combating the proapoptotic molecule Bim in control of naive and memory T cell homeostasis using Bcl-2−/− mice that were additionally deficient in one or both alleles of Bim. Naive T cells were significantly decreased in Bim+/−Bcl-2−/− mice, but were largely restored in Bim−/−Bcl-2−/− mice. Similarly, a synthetic Bcl-2 inhibitor killed wild-type, but not Bim−/−, T cells. Further, T cells from Bim+/−Bcl-2−/− mice died rapidly ex vivo and were refractory to cytokine-driven survival in vitro. In vivo, naive CD8+ T cells required Bcl-2 to combat Bim to maintain peripheral survival, whereas naive CD4+ T cells did not. In contrast, Bim+/−Bcl-2−/− mice generated relatively normal numbers of memory T cells after lymphocytic choriomeningitis virus infection. Accumulation of memory T cells in Bim+/−Bcl-2−/− mice was likely caused by their increased proliferative renewal because of the lymphopenic environment of the mice. Collectively, these data demonstrate a critical role for a balance between Bim and Bcl-2 in controlling homeostasis of naive and memory T cells.

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Analysis of Apoptosis of Memory T Cells and Dendritic Cells during the Early Stages of Viral Infection or Exposure to Toll-Like Receptor Agonists

Journal of Virology ◽

10.1128/jvi.02571-09 ◽

2010 ◽

Vol 84 (10) ◽

pp. 4866-4877 ◽

Cited By ~ 29

Author(s):

Kapil Bahl ◽

Anette Hüebner ◽

Roger J. Davis ◽

Raymond M. Welsh

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

Ex Vivo ◽

Annexin V ◽

Poly I:C ◽

Type I ◽

Memory T Cell ◽

Lcmv Infection

ABSTRACT Profound type I interferon (IFN-I)-dependent attrition of memory CD8 and CD4 T cells occurs early during many infections. It is dramatic at 2 to 4 days following lymphocytic choriomeningitis virus (LCMV) infection of mice and can be elicited by the IFN-inducing Toll receptor agonist poly(I:C). We show that this attrition occurs in many organs, indicating that it is due to T cell loss rather than redistribution. This loss correlated with elevated intracellular staining of T cells ex vivo for activated caspases but with only low levels of ex vivo staining with annexin V, probably due to the rapid clearance of apoptotic cells in vivo. Instead, a high frequency of annexin V-reactive CD8α+ dendritic cells (DCs), which are known to be highly phagocytic, accumulated in the spleen as the memory T cell populations disappeared. After short in vitro incubation, memory phenotype T cells isolated from LCMV-infected mice (day 3) or mice treated with poly(I:C) (12 h) displayed substantial DNA fragmentation, as detected by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, compared to T cells isolated from uninfected mice, indicating a role for apoptosis in the memory T cell attrition. This apoptosis of memory CD8 T cells early during LCMV infection was reduced in mice lacking the proapoptotic molecule Bim. Evidence is presented showing that high levels of T cell attrition, as found in young mice, correlate with reduced immunodomination by cross-reactive memory cells.

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Multimodal memory T cell profiling identifies a reduction in a polyfunctional Th17 state associated with tuberculosis progression

10.1101/2020.04.23.057828 ◽

2020 ◽

Cited By ~ 3

Author(s):

Aparna Nathan ◽

Jessica I. Beynor ◽

Yuriy Baglaenko ◽

Sara Suliman ◽

Kazuyoshi Ishigaki ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Memory T Cells ◽

Ex Vivo ◽

Surface Proteins ◽

Effector Memory ◽

Specific Cell ◽

Memory State ◽

Memory T Cell ◽

Cell State

AbstractMycobacterium tuberculosis (M.tb) results in 10 million active tuberculosis (TB) cases and 1.5 million deaths each year1, making it the world’s leading infectious cause of death2. Infection leads to either an asymptomatic latent state or TB disease. Memory T cells have been implicated in TB disease progression, but the specific cell states involved have not yet been delineated because of the limited scope of traditional profiling strategies. Furthermore, immune activation during infection confounds underlying differences in T cell state distributions that influence risk of progression. Here, we used a multimodal single-cell approach to integrate measurements of transcripts and 30 functionally relevant surface proteins to comprehensively define the memory T cell landscape at steady state (i.e., outside of active infection). We profiled 500,000 memory T cells from 259 Peruvians > 4.7 years after they had either latent M.tb infection or active disease and defined 31 distinct memory T cell states, including a CD4+CD26+CD161+CCR6+ effector memory state that was significantly reduced in patients who had developed active TB (OR = 0.80, 95% CI: 0.73–0.87, p = 1.21 × 10−6). This state was also polyfunctional; in ex vivo stimulation, it was enriched for IL-17 and IL-22 production, consistent with a Th17-skewed phenotype, but also had more capacity to produce IFNγ than other CD161+CCR6+ Th17 cells. Additionally, in progressors, IL-17 and IL-22 production in this cell state was significantly lower than in non-progressors. Reduced abundance and function of this state may be an important factor in failure to control M.tb infection.

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Akt Signalling Inhibition Promotes The Ex Vivo generation Of Minor Histocompatibility Antigen-Specific CD8+ Memory Stem T Cells

Blood ◽

10.1182/blood.v122.21.3269.3269 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3269-3269

Author(s):

Anniek B. van der Waart ◽

Noortje van der Weem ◽

Luca Gattinoni ◽

Nicolaas PM Schaap ◽

Robbert van der Voort ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Cd8 T Cells ◽

Memory T Cells ◽

Ex Vivo ◽

Akt Inhibitor ◽

Memory Subset

Abstract Allogeneic hematopoietic stem cell transplantation (allo-SCT) followed by donor lymphocyte infusion (DLI) is a potential curative treatment for patients suffering from a hematological malignancy. Efficacy is attributed to the graft-versus-tumor (GVT) response, during which engrafted donor T cells become activated by recipient minor histocompatibility antigens (MiHA) presented on dendritic cells (DC). Subsequently, these activated T cells expand, acquire effector functions and kill MiHA-positive tumor cells. However, persistence and recurrence of malignant disease is often observed, indicating that insufficient GVT immunity is induced. This imperfect alloreactive response is probably due to insufficient numbers of MiHA-specific effector T cells and/or defective antigen-presentation and costimulation. Therefore, adoptive transfer of potent ex vivo-generated MiHA-specific T cells, restricted to the hematopoietic system, would boost the GVT-effect without increasing the risk for GVHD. Although successful in vitro induction of MiHA-specific CD8+ T cells from naive precursors has been reported, the resulting antigen-experienced T cell population consist of fully differentiated effector-memory T cells (TEM). Over the past years it has been described that this T cell subset is not the most potent memory subset in anti-tumor responses in vivo following T cell transfer. In this regard, the less-differentiated memory subset called stem cell memory T cells (TSCM) with superior in vivo expansion, self-renewal capacity and plasticity to differentiate in potent effectors would generate a stronger GVT response. In this study, we aimed to investigate the in vivo availability and ex vivo generation of TSCM-like MiHA-specific T cells as additive treatment option for allo-SCT patients. First, we investigated whether in allo-SCT patients MiHA-specific T cells could be detected with a TSCM phenotype defined by the expression of CD45RO, CCR7, CD27 and CD95. Though TSCM cells could be clearly detected within CMV-specific CD8+ T cells in allo-SCT patients, similar to healthy controls, no MiHA-specific TSCM cells could be detected. This emphasises the need for more potent adoptive MiHA-specific T cell therapy following allo-SCT. Therefore, we next explored the possibility of generating TSCM-like CD8+ T cells by interfering with the Akt signalling pathway. Emerging findings indicate that the differentiation program of CD8+ T cells is dictated by the strength and duration of AKT activity. Therefore, we explored whether the pharmacological inhibition of this signaling pathway could results in the generation of TSCM-like CD8+ T cells. We stimulated CCR7+CD45RA+ naive CD8+ T cells with CD3/CD28 beads plus IL-2, IL-7 and/or IL-15 in the presence an Akt inhibitor. Interestingly, CD8+ T cells in these Akt-cultures were inhibited in their differentiation stage, expressing higher levels of CD45RA and CCR7 compared to controls. In addition, expression of CD95, IL2Rβ, and IL7Rα was also elevated confirming the TSCM-like phenotype. Although proliferation of the Akt-inhibited CD8+ T cells was decreased as shown by less PBSE dilution, expansion could be significantly preserved. Next, we investigated whether the established culture conditions could be used to generate MiHA-specific TSCM-like cells. Therefore, CD8+ T cells from MiHA-negative donors were primed using autologous MiHA peptide-loaded moDCs in the presence of the Akt-inhibitor. Interestingly, MiHA-specific T cell priming could be induced, consisting of mainly TCM and TSCM-like cells compared to almost entirely TEM cells in the control setting. Akt-inhibited MiHA-specific T cells showed higher expression of CCR7, CD45RA, CD62L, CD28, CD95, and IL7Rα. Importantly, for the Akt-inhibited MiHA-specific T cells, proliferation was reserved, resulting in robust proliferation capacity during restimulation after removal of the Akt-inhibitor. The resulting TEFF cells were highly functional, showing capacity to degranulate and produce IFNγ upon peptide restimulation. In conclusion, by inhibiting the Akt-pathway, in vitro CD8+ T cell differentiation can be reduced. Therefore, Akt signalling inhibition can be exploited for generating TSCM-like MiHA-specific T cells in adoptive immunotherapy after allo-SCT. Disclosures: No relevant conflicts of interest to declare.

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Normal Numbers of Stem Cell Memory T Cells Despite Strongly Reduced Naive T Cells Support Intact Memory T Cell Compartment in Ataxia Telangiectasia

Frontiers in Immunology ◽

10.3389/fimmu.2021.686333 ◽

2021 ◽

Vol 12 ◽

Author(s):

Thomas J. Weitering ◽

Janine E. Melsen ◽

Monique M. van Ostaijen-ten Dam ◽

Corry M. R. Weemaes ◽

Marco W. Schilham ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Ataxia Telangiectasia ◽

Memory T Cells ◽

Spectral Flow ◽

Normal Numbers ◽

Cell Compartment ◽

Cell Memory ◽

Memory T Cell

Ataxia Telangiectasia (AT) is a rare inherited disorder characterized by progressive cerebellar ataxia, chromosomal instability, cancer susceptibility and immunodeficiency. AT is caused by mutations in the ATM gene, which is involved in multiple processes linked to DNA double strand break repair. Immunologically, ATM mutations lead to hampered V(D)J recombination and consequently reduced numbers of naive B and T cells. In addition, class switch recombination is disturbed resulting in antibody deficiency causing common, mostly sinopulmonary, bacterial infections. Yet, AT patients in general have no clinical T cell associated infections and numbers of memory T cells are usually normal. In this study we investigated the naive and memory T cell compartment in five patients with classical AT and compared them with five healthy controls using a 24-color antibody panel and spectral flow cytometry. Multidimensional analysis of CD4 and CD8 TCRαβ+ cells revealed that early naive T cell populations, i.e. CD4+CD31+ recent thymic emigrants and CD8+CCR7++CD45RA++ T cells, were strongly reduced in AT patients. However, we identified normal numbers of stem cell memory T cells expressing CD95, which are antigen-experienced T cells that can persist for decades because of their self-renewal capacity. We hypothesize that the presence of stem cell memory T cells explains why AT patients have an intact memory T cell compartment. In line with this novel finding, memory T cells of AT patients were normal in number and expressed chemokine receptors, activating and inhibitory receptors in comparable percentages as controls. Comparing memory T cell phenotypes by Boolean gating revealed similar diversity indices in AT compared to controls. We conclude that AT patients have a fully developed memory T cell compartment despite strongly reduced naive T cells. This could be explained by the presence of normal numbers of stem cell memory T cells in the naive T cell compartment, which support the maintenance of the memory T cells. The identification of stem cell memory T cells via our spectral flow cytometric approach is highly relevant for better understanding of T cell immunity in AT. Moreover, it provides possibilities for further research on this recently identified T cell population in other inborn errors of immunity.

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Creating space: an antigen-independent, CpG-induced peripheral expansion of naive and memory T lymphocytes in a full T-cell compartment

Blood ◽

10.1182/blood-2002-02-0401 ◽

2002 ◽

Vol 100 (7) ◽

pp. 2537-2545 ◽

Cited By ~ 42

Author(s):

Eduardo Davila ◽

Maria G. Velez ◽

Carrie J. Heppelmann ◽

Esteban Celis

Keyword(s):

T Cells ◽

T Cell ◽

Memory T Cells ◽

Repeated Administration ◽

T Cell Subsets ◽

Cpg Odn ◽

T Cell Homeostasis ◽

Cell Compartment ◽

Cell Homeostasis ◽

Steady State Levels

Many of the mechanisms that govern T-cell homeostasis remain obscure. Here we report that repeated administration of synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG-ODN) into mice induces a systemic antigen-independent expansion of naive and memory T cells in a full T-cell compartment. Expansion of T cells was observed on both CD4+ and CD8+ T-cell subsets and was produced not by inducing the proliferation of the cells but by preventing their death. The antiapoptotic effects of CpG-ODN on T cells were observed against activation-induced death and growth factor withdrawal–mediated death. The ability of CpG-ODN to protect T cells from these forms of death was associated with the up-regulation of antiapoptotic gene products including c-FLIP, bcl-xL, and, to some extent, bcl-2. The effect of CpG-ODN on naive and memory T cells required the expression of CD28 and was not dependent on the presence of B lymphocytes, suggesting that other antigen-presenting cells that respond to CpG-ODN, such as dendritic cells, may provide antiapoptotic signals to T cells in an antigen-independent but CD28/B7-dependent fashion. The present findings suggest that CpG-ODN can disrupt normal T-cell homeostasis not by acting as a mitogen but by preventing T-cell death that normally takes place as a mechanism to maintain steady-state levels of T cells. These findings support a potential means to expeditiously replenish and maintain the peripheral lymphocyte population after severe immunodepletion such as that which occurs in HIV-infected individuals and individuals undergoing cytoablative therapies.

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p65/RelA Modulates BECN1 Transcription and Autophagy

Molecular and Cellular Biology ◽

10.1128/mcb.01396-08 ◽

2009 ◽

Vol 29 (10) ◽

pp. 2594-2608 ◽

Cited By ~ 156

Author(s):

Tamara Copetti ◽

Cosetta Bertoli ◽

Emiliano Dalla ◽

Francesca Demarchi ◽

Claudio Schneider

Keyword(s):

T Cells ◽

T Cell ◽

Cell Receptor ◽

Cellular Systems ◽

Jurkat Cells ◽

T Cell Homeostasis ◽

Cell Homeostasis ◽

Protein Levels ◽

Autophagy Induction

ABSTRACT Recently, autophagy has emerged as a critical process in the control of T-cell homeostasis. Given the pivotal role of NF-κB in the signaling events of T cells, we have analyzed and unveiled a conserved NF-κB binding site in the promoter of the murine and human BECN1 autophagic gene (Atg6). Accordingly, we demonstrate that the NF-κB family member p65/RelA upregulates BECN1 mRNA and protein levels in different cellular systems. Moreover, p65-mediated upregulation of BECN1 is coupled to increased autophagy. The newly identified κB site in the BECN1 promoter specifically interacts with p65 both in vitro and in living Jurkat cells upon phorbol myristate acetate (PMA)-ionomycin stimulation, where p65 induction is coupled to BECN1 upregulation and autophagy induction. Finally, anti-CD3- and PMA-ionomycin-mediated activation of T-cell receptor signaling in peripheral T cells from lymph nodes of healthy mice results in an upregulation of BECN1 expression that can be blocked by the NF-κB inhibitor BAY 11-7082. Altogether, these data suggest that autophagy could represent a novel route modulated by p65 to regulate cell survival and control T-cell homeostasis.

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The BCL-2-Selective Inhibitor Venetoclax Spares Activated T-Cells during Anti-Tumor Immunity

Blood ◽

10.1182/blood-2018-99-113134 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3704-3704 ◽

Cited By ~ 3

Author(s):

Rebecca Mathew ◽

Dipica Haribhai ◽

Fred Kohlhapp ◽

Ryan Duggan ◽

Paul Ellis ◽

...

Keyword(s):

T Cells ◽

Immune System ◽

T Cell ◽

Immune Checkpoint ◽

Memory T Cells ◽

Checkpoint Inhibitors ◽

Critical Role ◽

Tumor Model

Abstract Introduction and objectives: During an adaptive immune response antigen-specific T cells rapidly proliferate and differentiate into cytotoxic T lymphocytes. Most of these cells undergo apoptosis but some develop into high-affinity memory CD8+ T cells. The BCL-2 family of proteins regulates apoptosis and has a critical role in development and maintenance of the immune system. Venetoclax (Venclexta™, ABT-199) is a selective BCL-2 inhibitor that increases tumor cell apoptosis, and is approved by the FDA for patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), with or without 17p deletion, who have received at least one prior therapy. Given the critical role of BCL-2 in the regulation of the immune system, we hypothesized that venetoclax may affect the anti-tumor activity of immune checkpoint inhibitors. Results: To interrogate the effects of venetoclax on T cells we initially performed a series of in vitro studies using human lymphocytes treated with clinically relevant doses of the drug. As previously reported (Khaw et al., Leukemia; 28(6):1207-1215, 2014), human peripheral blood mononuclear cells (PBMCs) treated with venetoclax exhibited a dose-dependent decrease in the number of B-cells and T-cells (CD4+ and CD8+ T-cells). Upon further characterization of the surviving T cells, we found that while the proportion of naïve T-cells decreased with increasing venetoclax concentrations, the proportion of memory T-cells increased, specifically CD8+ and CD4+ T effector memory cells (Figure 1). We next examined the effects of venetoclax on T-cell function in vitro in response to immune stimulation with or without immune checkpoint blockade. To address this we performed a mixed lymphocyte reaction (MLR) assay, in which primary monocyte-derived dendritic cells from one donor were cultured with CD4+ T-cells from another donor. In the MLR reaction we observed that venetoclax reduced CD4+ T-cell viability in a dose-dependent manner, but it did not limit T-cell proliferation of surviving cells. Venetoclax did not affect IFNγ secretion within these surviving cells and, more importantly, did not reduce the effects of the checkpoint inhibitor nivolumab (Figure 2). To test the effects of venetoclax on antigen-specific T cells, we performed a cytomegalovirus (CMV) recall assay where PBMCs from CMV-positive human subjects were incubated with CMV antigen and the activity of T cells was measured by IFNg secretion. Although venetoclax treatment reduced the total number of cells, IFNg production from antigen-specific CMV+ T cells remained comparable to DMSO control and combining venetoclax with nivolumab did not affect the anti-PD-1 response (Figure 3). Finally, to investigate the effects of venetoclax in combination with anti-PD-1 therapy in vivo we used the murine syngeneic tumor model MC38. Venetoclax did not impair the efficacy of anti-PD-1, and in some studies increased efficacy relative to either anti-PD-1 or venetoclax monotherapy alone. To determine whether the efficacy of the venetoclax-anti-PD-1 combination is immune-mediated, we transplanted immunodeficient mice with MC38 cells and repeated the same treatment regimens. The lack of efficacy in any of the treatment arms indicates that the contribution of venetoclax to efficacy in this solid tumor model is immune-mediated (Figure 4). Conclusions: These data suggest that venetoclax treatment results in loss of naïve but not memory T cells. Venetoclax did not affect the viability, the induction or frequency of memory T cells. In human in vitro experiments and in an in vivo syngeneic tumor model venetoclax did not antagonize the therapeutic effect of anti-PD-1. Contrary to our initial hypothesis, we find that modulation of the immune system by venetoclax may support its potential use for immune-based cancer therapy, as memory T-cells can rapidly acquire effector and cytotoxic function to eliminate cancer cells. Taken together, we provide evidence that venetoclax in combination with immune checkpoint inhibitors should be further explored as a therapy for cancer patients. All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie and Genentech participated in the interpretation of data, review, and approval of the publication. Disclosures Mathew: AbbVie Inc.: Employment. Haribhai:AbbVie Inc.: Employment. Kohlhapp:AbbVie Inc.: Employment. Duggan:AbbVie Inc.: Employment. Ellis:AbbVie Inc.: Employment. Riehm:AbbVie Inc.: Employment. Robinson:AbbVie Inc.: Employment. Shi:AbbVie Inc.: Employment. Bhathena:AbbVie Inc.: Employment. Leverson:AbbVie Inc: Employment, Equity Ownership, Patents & Royalties. Pappano:AbbVie Inc.: Employment. Donawho:AbbVie Inc.: Employment. Uziel:AbbVie Inc.: Employment.

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T Cell Lymphopenia in Rhoh−/− Mice Results from Combined Defects of T Cell Migration and IL-7-Regulated Naïve T Cell Homeostasis.

Blood ◽

10.1182/blood.v108.11.872.872 ◽

2006 ◽

Vol 108 (11) ◽

pp. 872-872

Author(s):

ShuShun Li ◽

David A. Hildeman ◽

H. Leighton Grimes ◽

David A. Williams ◽

Yi Gu

Keyword(s):

T Cells ◽

Cell Migration ◽

T Cell ◽

Cell Survival ◽

T Cell Homeostasis ◽

Cell Homeostasis ◽

T Cell Migration ◽

T Cell Lymphopenia ◽

T Cell Survival

Abstract The Rho family GTPases are increasingly implicated for their important roles in T cell development and function. We have found that RhoH, a hematopoietic-specific member of this family is essential for thymocyte development (Gu et al, Nat Immunol, in press). Further, Rhoh−/− mice showed T cell lymphopenia. In particular, naïve T cells were reduced in secondary lymphoid organs and blood both in unchallenged and LCMV-challenged Rhoh−/− mice compared to WT controls. These findings suggest a possible defect in T cell emigration from thymus and peripheral T cell homeostasis in Rhoh−/− mice. To study the role(s) of RhoH in T cell migration and homeostasis, purified splenic T cells were adoptively transferred into common γ−/−; Rag2−/− mice. T cells were then recovered from spleens 3d and 8d post-transplantation. The recovery of Rhoh−/− T cells was decreased by 60% compared with WT cells. In vitro migration of Rhoh−/− T cells towards SDF-1α, a homeostatic chemokine for T cells, in a transwell migration assay was significantly reduced compared to WT cells. Flow analysis showed decreased number of CXCR4 expressing and reduced expression levels of CXCR4 on Rhoh−/− T cells. Furthermore, apoptotic T cells were increased twofold in Rhoh−/− mice compared to controls. CFSE staining of adoptively transferred T cells demonstrated a comparable proliferation rate between Rhoh−/− and WT cells in the recipient mice. Our data suggest that RhoH plays an important role in T cell homeostasis via regulating cell survival and SDF-1α-mediated migration. To further investigate how RhoH regulates T cell survival, we focused on IL-7, an essential factor for prolonged survival of naïve T cells. One way IL-7 exerts its effect is through upregulating the Bcl-2 family of antiapoptotic proteins. Our data showed that in vitro survival of Rhoh−/− T cells in response to IL-7 was impaired, and expression of IL-7Rα and Bcl-2 were both decreased in Rhoh−/− T cells. To further study a potential role of RhoH in regulation of IL-7R expression, FACsvantage sorted naïve T cells (CD4+CD44low, or CD8+CD44low) were cytokine starved overnight, then cultured with or without the addition of IL-7 for 6 hrs, and analyzed for IL-7Rα expression by flow cytometry. In WT cells, during cytokine starvation CD4 and a subset of CD8 naïve cells upregulated IL-7Rα expression, but this upregulation was reduced followed IL-7 stimulation. In contrast, Rhoh−/− T cells failed to show either up- or subsequent down-regulation of IL-7Rα in response to cytokine starvation and IL-7 exposure. These data may indicate a role for RhoH in regulating IL-7R expression in naïve CD4 T cells. Taken together, these findings suggest that RhoH is required for IL-7-mediated T cell survival and SDF-1α-mediated homing and/or emigration from thymus. Thus, deficiency of naïve T cells in Rhoh−/− mice likely results from combined defects in T cell migration and homeostasis.

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Interleukin-2 enhances CD4+ T cell memory by promoting the generation of IL-7Rα–expressing cells

Journal of Experimental Medicine ◽

10.1084/jem.20062381 ◽

2007 ◽

Vol 204 (3) ◽

pp. 547-557 ◽

Cited By ~ 121

Author(s):

Hans Dooms ◽

Kristen Wolslegel ◽

Patricia Lin ◽

Abul K. Abbas

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Interleukin 2 ◽

T Cell Response ◽

T Cell Homeostasis ◽

Activation Markers ◽

Term Survival ◽

Cell Homeostasis ◽

Memory T Cell

The common γ chain cytokines interleukin (IL)-2 and IL-7 are important regulators of T cell homeostasis. Although IL-2 is implicated in the acute phase of the T cell response, IL-7 is important for memory T cell survival. We asked whether regulated responsiveness to these growth factors is determined by temporal expression of the cytokine-specific IL-2 receptor (R) α and IL-7Rα chains. We demonstrate that IL-2Rα is expressed early after priming in T cell receptor–transgenic CD4+ T cells, whereas IL-7Rα expression is lost. In the later stage of the response, IL-7Rα is reexpressed while IL-2Rα expression is silenced. This reciprocal pattern of IL-2Rα/IL-7Rα expression is disturbed when CD4+ T cells are primed in the absence of IL-2 signals. Primed IL-2−/− or CD25−/− (IL-2Rα−/−) CD4+ T cells, despite showing normal induction of activation markers and cell division, fail to reexpress IL-7Rα late in the response. Because the generation of CD4+ memory T cells is dependent on IL-7–IL-7Rα interactions, primed IL-2−/− or CD25−/− CD4+ T cells develop poorly into long-lived memory cells. Retrovirus-mediated expression of IL-7Rα in IL-2−/− T cells restores their capacity for long-term survival. These results identify IL-2 as a factor regulating IL-7Rα expression and, consequently, memory T cell homeostasis in vivo.

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