CD8+CD122+CD49dlow regulatory T cells maintain T-cell homeostasis by killing activated T cells via Fas/FasL-mediated cytotoxicity

The Fas/FasL (CD95/CD178) system is required for immune regulation; however, it is unclear in which cells, when, and where Fas/FasL molecules act in the immune system. We found that CD8+CD122+ cells, which are mostly composed of memory T cells in comparison with naïve cells in the CD8+CD122− population, were previously shown to include cells with regulatory activity and could be separated into CD49dlow cells and CD49dhigh cells. We established in vitro and in vivo experimental systems to evaluate the regulatory activity of CD122+ cells. Regulatory activity was observed in CD8+CD122+CD49dlow but not in CD8+CD122+CD49dhigh cells, indicating that the regulatory cells in the CD8+CD122+ population could be narrowed down to CD49dlow cells. CD8+CD122− cells taken from lymphoproliferation (lpr) mice were resistant to regulation by normal CD122+ Tregs. CD122+ Tregs taken from generalized lymphoproliferative disease (gld) mice did not regulate wild-type CD8+CD122− cells, indicating that the regulation by CD122+ Tregs is Fas/FasL-dependent. CD122+ Tregs taken from IL-10–deficient mice could regulate CD8+CD122− cells as equally as wild-type CD122+ Tregs both in vitro and in vivo. MHC class I-missing T cells were not regulated by CD122+ Tregs in vitro. CD122+ Tregs also regulated CD4+ cells in a Fas/FasL-dependent manner in vitro. These results suggest an essential role of Fas/FasL as a terminal effector of the CD122+ Tregs that kill activated T cells to maintain immune homeostasis.

Download Full-text

Essential Roles of CD8+CD122+ Regulatory T Cells in the Maintenance of T Cell Homeostasis

Journal of Experimental Medicine ◽

10.1084/jem.20040395 ◽

2004 ◽

Vol 200 (9) ◽

pp. 1123-1134 ◽

Cited By ~ 196

Author(s):

Muhaimin Rifa'i ◽

Yoshiyuki Kawamoto ◽

Izumi Nakashima ◽

Haruhiko Suzuki

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Wild Type ◽

T Cell Homeostasis ◽

Activated T Cells ◽

Naturally Occurring ◽

Recombination Activating Gene ◽

Β Chain

Regulation of immune system is of paramount importance to prevent immune attacks against self-components. Mice deficient in the interleukin (IL)-2/IL-15 receptor β chain, CD122, are model animals of such immune attacks and characteristically have a high number of abnormally activated T cells. Here, we show that the transfer of CD8+CD122+ cells into CD122-deficient neonates totally prevented the development of abnormal T cells. Furthermore, recombination activating gene–2−/− mice that received wild-type mice–derived CD8+CD122− cells died within 10 wk after cell transfer, indicating that normal CD8+CD122− cells become dangerously activated T cells in the absence of CD8+CD122+ T cells. CD8+CD122+ cells could control activated CD8+ or CD4+ T cells both in vivo and in vitro. Our results indicate that the CD8+CD122+ population includes naturally occurring CD8+ regulatory T cells that control potentially dangerous T cells.

Download Full-text

Human Endothelial Cells Enhance Human Immunodeficiency Virus Type 1 Replication in CD4+ T Cells in a Nef-Dependent Manner In Vitro and In Vivo

Journal of Virology ◽

10.1128/jvi.79.1.264-276.2005 ◽

2005 ◽

Vol 79 (1) ◽

pp. 264-276 ◽

Cited By ~ 20

Author(s):

Jaehyuk Choi ◽

Jason Walker ◽

Sergei Boichuk ◽

Nancy Kirkiles-Smith ◽

Nicholas Torpey ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Dependent Manner ◽

Wild Type ◽

Mhc Ii ◽

Hiv 1

ABSTRACT Infected CD4+ T cells are the primary sites of human immunodeficiency virus type 1 (HIV-1) replication in vivo. However, signals from professional antigen-presenting cells (APCs), such as dendritic cells and macrophages, greatly enhance HIV-1 replication in T cells. Here, we report that in cocultures, vascular endothelial cells (ECs), which in humans can also serve as APCs, can enhance HIV-1 production of both CCR5- and CXCR4-utilizing strains approximately 50,000-fold. The observed HIV-1 replication enhancement conferred by ECs occurred only in memory CD4+ T cells, required expression of major histocompatibility complex class II (MHC-II) molecules by the ECs, and could not be conferred by fixed ECs, all of which are consistent with a requirement for EC-mediated T-cell activation via T-cell receptor (TCR) signaling. Deletion of nef (Nef−) decreased HIV-1 production by approximately 100-fold in T cells cocultured with ECs but had no effect on virus production in T cells cocultured with professional APCs or fibroblasts induced to express MHC-II. Human ECs do not express B7 costimulators, but Nef− replication in CD4+-T-cell and EC cocultures could not be rescued by anti-CD28 antibody. ECs act in trans to enhance wild-type but not Nef− replication and facilitate enhanced wild-type replication in naïve T cells when added to T-cell or B-lymphoblastoid cell cocultures, suggesting that ECs also provide a TCR-independent signal to infected T cells. Consistent with these in vitro observations, wild-type HIV-1 replicated 30- to 50-fold more than Nef− in human T cells infiltrating allogeneic human skin grafts on human huPBL-SCID/bg mice, an in vivo model of T-cell activation by ECs. Our studies suggest that ECs, which line the entire cardiovascular system and are, per force, in frequent contact with memory CD4+ T cells, provide signals to HIV-1-infected CD4+ T cells to greatly enhance HIV-1 production in a Nef-dependent manner, a mechanism that could contribute to the development of AIDS.

Download Full-text

Critical Role for CCR1:CCL5 (RANTES) Receptor Ligand Interactions in Modulating Allogeneic T Cell Responses Following Bone Marrow Transplantation.

Blood ◽

10.1182/blood.v106.11.3107.3107 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3107-3107

Author(s):

Sung Won Choi ◽

Gerhard C. Hildebrandt ◽

Ines Silva ◽

Krystyna M. Olkiewicz ◽

Stephen W. Chensue ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Critical Role ◽

T Cell Responses ◽

Dependent Manner ◽

Activated T Cells ◽

Cell Responses

Abstract Acute graft versus host disease (GVHD) and leukemic relapse are the most serious complications of allogeneic (allo) stem cell transplantation (SCT), and separating desirable graft-versus-leukemia (GVL) effects from GVHD remains the ultimate challenge to successful outcomes. The recruitment of activated T cells to host target tissues (GVHD) or sites of leukemic infiltration (GVL) is likely mediated by chemokine receptor:ligand interactions. CCR1 is a chemokine receptor that binds to CC chemokines including RANTES (CCL5), and is expressed on a variety of cells including activated T cells, monocytes, and macrophages. We have previously shown that mRNA expression of both CCR1 and RANTES is increased in GVHD target tissues following allo-SCT. Using a well established murine SCT model (B6->B6D2F1) and mice deficient in CCR1, we examined the contribution of CCR1 expression to allo T cell responses in vitro and to GVH and GVL effects in vivo. Lethally (1100cGy) irradiated B6D2F1 mice received SCT either from syngeneic (B6D2F1) or allogeneic (B6) CCR1+/+ or CCR1−/− donors. The severity of GVHD was assessed by survival and a well described clinical scoring system. Syngeneic SCT recipients all survived and were indistinguishable from naïve, untransplanted controls, whereas animals receiving allo-SCT from CCR1+/+ donors developed significant GVHD. By contrast, allo-SCT with CCR1−/− donor cells resulted in significantly improved survival (92% vs. 50%) and less severe clinical GVHD (p<0.01) by day 35 compared to allo-CCR1+/+ controls. GVL effects were next assessed by adding 500 P815 tumor cells (H-2d and syngeneic to host) to the bone marrow inoculum on day 0. F1 recipients of syngeneic BMT all died from tumor infiltration by day +15. Although all allo-SCT recipients effectively rejected their tumor, mice receiving CCR1-/− SCT had significantly improved leukemia free survival (45% vs. 5%) by day 60 compared to allo controls. At higher tumor doses, significant GVL activity remained in CCR1−/− SCT recipients, but the survival advantage was lost. Further examination of allo T cell responses in vivo revealed that day 7 splenic T cell expansion and serum IFNγ levels were significantly lower following CCR1−/− SCT (p < 0.01). Surprisingly, proliferation and IFNγ secretion were also reduced by ~70% when CCR1−/− T cells were stimulated with host antigens in vitro, whereas CTL activity remained equivalent to CCR1+/+ controls. The reduction in proliferation was not secondary to a migration defect, but was dependent on interactions between CCR1 and RANTES; neutralization of RANTES with a monoclonal antibody significantly reduced proliferation of CCR1+/+ T cells in a dose dependent manner. Finally, we found that GVHD mortality was also less when RANTES−/− mice were used as recipients in a second, MHC-disparate, SCT model (p = 0.03). Collectively these data demonstrate a critical role for CCR1 in donor T cell alloreactivity following SCT. These responses contribute to both GVHD and GVL effects in vivo and are likely dependent upon interactions between CCR1 and the chemokine ligand RANTES.

Download Full-text

Estrogen Up-Regulates Hepatic Expression of Suppressors of Cytokine Signaling-2 and -3 in Vivo and in Vitro

Endocrinology ◽

10.1210/en.2004-0061 ◽

2004 ◽

Vol 145 (12) ◽

pp. 5525-5531 ◽

Cited By ~ 50

Author(s):

Gary M. Leong ◽

Sofia Moverare ◽

Jesena Brce ◽

Nathan Doyle ◽

Klara Sjögren ◽

...

Keyword(s):

Promoter Activity ◽

Hepatoma Cells ◽

Cytokine Signaling ◽

Mrna Levels ◽

Dependent Manner ◽

Wild Type ◽

Hepatic Expression ◽

Suppressors Of Cytokine Signaling

Abstract Suppressors of cytokine signaling (SOCS) are important negative regulators of cytokine action. We recently reported that estrogen stimulates SOCS-2 expression and inhibits GH signaling in kidney cells. The effects of estrogen on SOCS expression in other tissues are unclear. The aim of this study was to investigate in vivo and in vitro whether estrogen affected SOCS expression in the liver, a major target organ of GH. The in vivo hepatic effects of estrogen on ovariectomized mice lacking estrogen receptor (ER)-α, ERβ, or both and their wild-type littermates were examined by DNA microarray analysis. In vitro, the effects of estrogen on SOCS expression in human hepatoma cells were examined by reverse transcription quantitative PCR. Long-term (3 wk) estrogen treatment induced a 2- to 3-fold increase in hepatic expression of SOCS-2 and -3 in wild-type and ERβ knockout mice but not in those lacking ERα or both ER subtypes. Short-term treatment (at 24 h) increased the mRNA level of SOCS-3 but not SOCS-2. In cultured hepatoma cells, estrogen increased SOCS-2 and -3 mRNA levels by 2-fold in a time- and dose-dependent manner (P < 0.05). Estrogen induced murine SOCS-3 promoter activity by 2-fold (P < 0.05) in constructs containing a region between nucleotides −1862 and −855. Moreover, estrogen and GH had additive effects on the SOCS-3 promoter activity. In summary, estrogen, via ERα, up-regulated hepatic expression of SOCS-2 and -3, probably through transcriptional activation. This indicates a novel mechanism of estrogen regulation of cytokine action.

Download Full-text

Cytokine-induced survival of activated T cells in vitro and in vivo

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.95.7.3810 ◽

1998 ◽

Vol 95 (7) ◽

pp. 3810-3815 ◽

Cited By ~ 284

Author(s):

A. T. Vella ◽

S. Dow ◽

T. A. Potter ◽

J. Kappler ◽

P. Marrack

Keyword(s):

T Cells ◽

Activated T Cells

Download Full-text

Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

10.1101/2021.04.05.438547 ◽

2021 ◽

Author(s):

Fatima Amanat ◽

Shirin Strohmeier ◽

Wen-Hsin Lee ◽

Sandhya Bangaru ◽

Andrew B Ward ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Severe Acute Respiratory Syndrome ◽

Mouse Model ◽

Neutralizing Antibodies ◽

Dependent Manner ◽

Receptor Binding Domain ◽

Wild Type ◽

Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

Download Full-text

Venetoclax enhances T cell-mediated anti-leukemic activity by increasing ROS production

Blood ◽

10.1182/blood.2020009081 ◽

2021 ◽

Author(s):

JongBok Lee ◽

Dilshad H. Khan ◽

Rose Hurren ◽

Mingjing Xu ◽

Yoosu Na ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mechanism Of Action ◽

Adoptive Cell Therapy ◽

Complete Response ◽

Ros Generation ◽

Activated T Cells ◽

Treatment Naïve

Venetoclax, a Bcl-2 inhibitor, in combination with the hypomethylating agent, Azacytidine, achieves complete response with or without count recovery in approximately 70% of treatment-naïve elderly patients unfit for conventional intensive chemotherapy. However, the mechanism of action of this drug combination is not fully understood. We discovered that Venetoclax directly activated T cells to increase their cytotoxicity against AML in vitro and in vivo. Venetoclax enhanced T cell effector function by increasing ROS generation through inhibition of respiratory chain supercomplexes formation. In addition, Azacytidine induced a viral-mimicry response in AML cells by activating the STING/cGAS pathway, thereby rendering the AML cells more susceptible to T-cell mediated cytotoxicity. Similar findings were seen in patients treated with Venetoclax as this treatment increased ROS generation and activated T cells. Collectively, this study demonstrates a new immune mediated mechanism of action for Venetoclax and Azacytidine in the treatment of AML and highlights a potential combination of Venetoclax and adoptive cell therapy for patients with AML.

Download Full-text

IMMUNOLOGIC REACTIONS TO HAPTENS ON AUTOLOGOUS CARRIERS

Journal of Experimental Medicine ◽

10.1084/jem.137.2.411 ◽

1973 ◽

Vol 137 (2) ◽

pp. 411-423 ◽

Cited By ~ 27

Author(s):

John W. Moorhead ◽

Curla S. Walters ◽

Henry N. Claman

Keyword(s):

T Cells ◽

B Cells ◽

Aminocaproic Acid ◽

Single Amino Acid ◽

Secondary Response ◽

Spleen Cells ◽

Activated T Cells ◽

Thymus Cells

Both thymus-derived (T) and bone marrow-derived (B) lymphocytes participate in the response to a hapten 4-hydroxy-3-iodo-5-nitrophenylacetic acid (NIP), coupled to a nonimmunogenic isologous carrier, mouse gamma globulin (MGG). Spleen cells from mice immunized with NIP-MGG show increased DNA synthesis in vitro when cultured with NIP-MGG. The participation of and requirement for T cells in the response was demonstrated by treating the spleen cells with anti-θ serum. This treatment resulted in a 77% inhibition of the antigen response. Furthermore, adoptively transferred normal thymus cells could be specifically "activated" by NIP-MGG in vivo and they responded secondarily to the antigen in vitro. The active participation of B cells in the secondary response was demonstrated by passing the immune spleen cells through a column coated with polyvalent anti-MGG serum. Column filtration reduced the number of NIP-specific plaque-forming cells and NIP-specific rosette-forming cells (both functions of B cells) and produced a 47% inhibition of the NIP-MGG response. The ability of the cells to respond to phytohemagglutinin (PHA) was not affected by column filtration showing that T cells were not being selectively removed. The participation of B cells in the in vitro NIP-MGG response was also shown by treatment of the spleen cells with antiserum specific for MGG and MGG determinants. B cells were removed by treatment with anti-IgM or polyvalent anti-MGG serum plus complement, resulting in a respective 46 and 49% inhibition of the response to NIP-MGG. (Treatment with anti-IgM serum had no effect on T cells.) The contribution of the hapten NIP to stimulation of T cells was investigated using NIP-MGG-activated thymus cells. These activated T cells responded in vitro very well to the NIP-MGG complex but not to the MGG carrier alone demonstrating the requirement of the hapten for T cell stimulation. The response was also partially inhibited (41%) by incubating the activated cells with NIP coupled to a single amino acid (epsilon-aminocaproic acid) before addition of NIP-MGG. These results demonstrated that T cells recognize the hapten NIP when it is coupled to the isologous carrier MGG.

Download Full-text

Abstract 14366: T-lymphocytes May Contribute to Thrombus Formation in Patients With Acute Coronary Syndrome via Expression of Tissue Factor

Circulation ◽

10.1161/circ.132.suppl_3.14366 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Giovanni Cimmino ◽

Giovanni Ciccarelli ◽

Stefano Conte ◽

Grazia Pellegrino ◽

Luigi Insabato ◽

...

Keyword(s):

T Cells ◽

T Lymphocytes ◽

Tissue Factor ◽

Thrombus Formation ◽

Specific Antigen ◽

Activated T Cells ◽

Coronary Syndrome ◽

Stable Cad

Background: Activation of T-cells plays an important role in the pathophysiology of acute coronary syndromes (ACS). We have previously shown that plaques from ACS patients are characterized by a selective oligoclonal expansion of T-cells, indicating a specific, antigen-mediated recruitment of T-cells within the unstable lesions. We have also previously reported that activated T-cells in vitro express functional Tissue Factor (TF) on their surface. At the moment, however it is not known whether expression of TF by T-cells may contribute to thrombus formation in vivo. Methods: Blood was collected from the aorta and the coronary sinus of 13 NSTEMI and 10 stable CAD patients. CD3+ cells were selectively isolated and TF gene expression (real time PCR)and protein levels (western blot) were evaluated. In additional 7 STEMI patients, thrombotic formation material was obtained from the occluded coronary artery by catheter aspiration during primary PCI. TF expression in CD3+ cells was evaluated by immunohistochemistry and confocal microscopy. Results: Transcardiac TF expression in CD3+ cells was significantly higher in NSTEMI patients as compared to CD3+ cells obtained from stable CAD patients. Interestingly, thrombi aspirated from STEMI patients resulted enriched in CD3+cells, which expressed TF on their surface as shown in the figure. Conclusions: Our data demonstrate that in patients with ACS, T-lymphocytes may express surface TF, thus contributing to the process of thrombus formation. This finding may shed new light into the pathophysiologyof ACS.

Download Full-text

Abstract 5566: Recovery of Erk Signaling Restores Defective Angiogenesis and Arteriogenesis in Synectin-Deficient Animals

Circulation ◽

10.1161/circ.118.suppl_18.s_576-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Bin Ren ◽

Arpita Mukhopadhyay* ◽

Anthony A Lanahan ◽

Zhen W Zhuang ◽

Karen L Moodie ◽

...

Keyword(s):

Endothelial Cells ◽

Branching Morphogenesis ◽

Erk Signaling ◽

Dependent Manner ◽

Wild Type ◽

Erk Activation ◽

Arterial Development ◽

Constitutively Active

Background : Arterial morphogenesis is an important and poorly understood process. We have previously demonstrated that disruption of synectin gene expression in mice and zebrafish results in impaired arterial development and branching morphogenesis. Synectin null endothelial cells demonstrate reduced VEGF responsiveness in terms of migration, proliferation and differentiation and ERK-1/2 activation (Chittenden et al, Dev Cell 2006). Since ERK has been established as major participants in the regulation of cell growth and differentiation and Erk activation has been previously linked to arterial morphogenesis, we evaluated whether activation of Erk signaling in synectin disrupted mice and zebrafish as well as synectin KO arterial endothelial cells (ECs) would restore defective migration, arterial differentiation, angiogenesis and arteriogenesis. To stimulate ERK signaling we used partial inhibition of PI3-K activity to reduce Akt-dependent suppression of Raf1 activation or introduction of constitutively active ERK construct. Methods : In vitro studies were conducted with primary arterial ECs isolated from synectin wild type (WT) and knock out (KO) mice. In vivo studies were carried out in WT and synectin deficient mice and synectin knockdown zebrafish embryos. Results: Exposure of synectin −/− arterial EC to two selective PI3K inhibitors GS4898 or LY294002 in vitro restored ERK activation in a dose-dependent manner and returned cell migration and in vitro branching morphogenesis to wild type levels. Transduction of a constitutively active ERK construct in vitro or in a Matrigel model in vivo had similar effect. Systemic treatment of synectin −/− mice with GS4898 fully restored impaired angiogenesis and arterial morphogenesis in adult animals in the setting of hindlimb ischemia. Similar treatment nearly completely restored arterial development defects in zebrafish treated with a synectin morpholino. Conclusions: ERK activation plays a key role in arteriogenesis both in adult tissues and during embryonic development. Activation of compromised ERK-1/2 signaling may be a novel therapeutic intervention to stimulate arteriogenesis.

Download Full-text