scholarly journals The Rho regulator Myosin IXb enables nonlymphoid tissue seeding of protective CD8+ T cells

2018 ◽  
Vol 215 (7) ◽  
pp. 1869-1890 ◽  
Author(s):  
Federica Moalli ◽  
Xenia Ficht ◽  
Philipp Germann ◽  
Mykhailo Vladymyrov ◽  
Bettina Stolp ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Small Gtpase ◽  
Basement Membranes ◽  
Negative Regulator ◽  
Skin Infections ◽  
Impaired Control ◽  
Nonlymphoid Tissue ◽  
Actomyosin Cytoskeleton

T cells are actively scanning pMHC-presenting cells in lymphoid organs and nonlymphoid tissues (NLTs) with divergent topologies and confinement. How the T cell actomyosin cytoskeleton facilitates this task in distinct environments is incompletely understood. Here, we show that lack of Myosin IXb (Myo9b), a negative regulator of the small GTPase Rho, led to increased Rho-GTP levels and cell surface stiffness in primary T cells. Nonetheless, intravital imaging revealed robust motility of Myo9b−/− CD8+ T cells in lymphoid tissue and similar expansion and differentiation during immune responses. In contrast, accumulation of Myo9b−/− CD8+ T cells in NLTs was strongly impaired. Specifically, Myo9b was required for T cell crossing of basement membranes, such as those which are present between dermis and epidermis. As consequence, Myo9b−/− CD8+ T cells showed impaired control of skin infections. In sum, we show that Myo9b is critical for the CD8+ T cell adaptation from lymphoid to NLT surveillance and the establishment of protective tissue–resident T cell populations.

Histone Deacetylase 11 (HDAC11) Regulates Cytotoxic T-Cell Function and Memory Phenotype

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 840-840
Author(s):  
David M Woods ◽  
Karrune V. Woan ◽  
Eva Sahakian ◽  
John Powers ◽  
Fengdong Cheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Central Memory ◽  
Negative Regulator ◽  
Wild Type ◽  
Potential Target ◽  
T Cell Function

Abstract Abstract 840 T-cells are an essential component of immune mediated tumor rejection. Adoptive transfer of T-cells results in a durable anti-tumor response in some patients with hematological malignancies. To further improve the efficacy of T-cell adoptive transfers, a better understanding of the regulatory checkpoints of these cells is needed. Here we show that HDAC11 is a negative regulator of CD8+ T-cell function, thus representing a potential target in adoptive immunotherapy. HDACs are a group of enzymes initially known for their role in deacetylating histones, thereby condensing chromatin structure and repressing gene expression. The known roles of HDACs as epigenetic regulators have recently expanded to include more complex regulatory functions including interactions with non-histone targets. HDAC11 is the most recently identified member of the HDAC family, and is highly expressed in brain, testis and T-cells. Recently, our group reported HDAC11 as a regulator of IL-10 production in antigen presenting cells. To determine the role of HDAC11 in T-cell biology, T-cells from HDAC11 knock out (HDAC11KO) mice were compared to wild-type T-cells in number, function and phenotype. HDAC11KO T-cells had no differences in absolute number or percentages of CD4+ or CD8+ lymphocytes. However CD8+ T-cells were hyper-proliferative upon CD3/CD28 stimulation and produced significantly higher levels of the pro-inflammatory, Tc1 cytokines IL-2, INF-γ, and TNF-α. However, no significant increases in the production of the Tc2 cytokines IL-4, IL-6 or IL-10 were seen. Further investigation of phenotypic differences also revealed that HDAC11KO mice have a larger percentage of central memory CD8+ T-cells. Additionally, HDAC11KO CD8+ T-cells express higher levels of the transcription factor Eomes, a known contributor to central memory cell formation as well as a controller of granzyme B and perforin production in CD8+ T-cells. This Tc1 and central memory-like phenotype translated to delayed tumor progression and survival in vivo in C1498 AML bearing mice treated with adoptively transferred HDAC11KO T-cells, as compared with wild type T-cells. Collectively, we have demonstrated HDAC11 as a negative regulator of CD8+ T-cell function, and a novel potential target to augment the efficacy of adoptive T-cell tumor immunotherapy. Disclosures: No relevant conflicts of interest to declare.

scholarly journals N-ras couples antigen receptor signaling to Eomesodermin and to functional CD8+ T cell memory but not to effector differentiation

2013 ◽  
Vol 210 (7) ◽  
pp. 1463-1479 ◽  
Author(s):  
Salvador Iborra ◽  
Manuel Ramos ◽  
David M. Arana ◽  
Silvia Lázaro ◽  
Francisco Aguilar ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Small Gtpase ◽  
T Cell Memory ◽  
Cell Memory ◽  
Cd8 T Cell Memory

Signals from the TCR that specifically contribute to effector versus memory CD8+ T cell differentiation are poorly understood. Using mice and adoptively transferred T lymphocytes lacking the small GTPase N-ras, we found that N-ras–deficient CD8+ T cells differentiate efficiently into antiviral primary effectors but have a severe defect in generating protective memory cells. This defect was rescued, although only partly, by rapamycin-mediated inhibition of mammalian target of rapamycin (mTOR) in vivo. The memory defect correlated with a marked impairment in vitro and in vivo of the antigen-mediated early induction of T-box transcription factor Eomesodermin (Eomes), whereas T-bet was unaffected. Besides N-ras, early Eomes induction in vitro required phosphoinositide 3-kinase (PI3K)–AKT but not extracellular signal-regulated kinase (ERK) activation, and it was largely insensitive to rapamycin. Consistent with N-ras coupling Eomes to T cell memory, retrovirally enforced expression of Eomes in N-ras–deficient CD8+ T cells effectively rescued their memory differentiation. Thus, our study identifies a critical role for N-ras as a TCR-proximal regulator of Eomes for early determination of the CD8+ T cell memory fate.

scholarly journals T Cell-Intrinsic CDK6 Is Dispensable for Anti-Viral and Anti-Tumor Responses In Vivo

2021 ◽  
Vol 12 ◽  
Author(s):  
Klara Klein ◽  
Agnieszka Witalisz-Siepracka ◽  
Dagmar Gotthardt ◽  
Benedikt Agerer ◽  
Felix Locker ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Type I ◽  
Cell Functions ◽  
Intrinsic Loss

The cyclin-dependent kinase 6 (CDK6) regulates the transition through the G1-phase of the cell cycle, but also acts as a transcriptional regulator. As such CDK6 regulates cell survival or cytokine secretion together with STATs, AP-1 or NF-κB. In the hematopoietic system, CDK6 regulates T cell development and promotes leukemia and lymphoma. CDK4/6 kinase inhibitors are FDA approved for treatment of breast cancer patients and have been reported to enhance T cell-mediated anti-tumor immunity. The involvement of CDK6 in T cell functions remains enigmatic. We here investigated the role of CDK6 in CD8+ T cells, using previously generated CDK6 knockout (Cdk6-/-) and kinase-dead mutant CDK6 (Cdk6K43M) knock-in mice. RNA-seq analysis indicated a role of CDK6 in T cell metabolism and interferon (IFN) signaling. To investigate whether these CDK6 functions are T cell-intrinsic, we generated a T cell-specific CDK6 knockout mouse model (Cdk6fl/fl CD4-Cre). T cell-intrinsic loss of CDK6 enhanced mitochondrial respiration in CD8+ T cells, but did not impact on cytotoxicity and production of the effector cytokines IFN-γ and TNF-α by CD8+ T cells in vitro. Loss of CDK6 in peripheral T cells did not affect tumor surveillance of MC38 tumors in vivo. Similarly, while we observed an impaired induction of early responses to type I IFN in CDK6-deficient CD8+ T cells, we failed to observe any differences in the response to LCMV infection upon T cell-intrinsic loss of CDK6 in vivo. This apparent contradiction might at least partially be explained by the reduced expression of Socs1, a negative regulator of IFN signaling, in CDK6-deficient CD8+ T cells. Therefore, our data are in line with a dual role of CDK6 in IFN signaling; while CDK6 promotes early IFN responses, it is also involved in the induction of a negative feedback loop. These data assign CDK6 a role in the fine-tuning of cytokine responses.

Abstract 585: E3 ubiquitin-protein Ligase Casitas B Lineage Lymphoma b Deficiency Aggravates Atherosclerosis

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Esther Smeets ◽  
Tom Seijkens ◽  
Myrthe den Toom ◽  
Svenja Meiler ◽  
Esther Lutgens
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Negative Regulator ◽  
Lymphoid Tissues ◽  
Cell Counts ◽  
Macrophage Apoptosis ◽  
Aortic Arches ◽  
B Lineage

E3 ubiquitin ligase Casitas B lineage Lymphoma b (Cbl-b) is a negative regulator in peripheral T cell activation. Cbl-b deficient T cells are hyper-reactive due to CD28-independent activation. Here we studied the effect of Cbl-b deficiency on T cell homeostasis in hypercholesterolemia and on atherogenesis in 20 wk old Cbl-b-/-/ApoE-/- mice. Flow cytometric analysis of lymphoid tissues and aortic arches showed decreased CD4+:CD8+ T cell ratios in Cbl-b-/-/ApoE-/- mice. Cbl-b deficiency induced central memory CD8+ T cells expansion, whereas the proportion of naïve T cells decreased. We found that Cbl-b deficient CD8+ T cells are less apoptotic as indicated by decreased AnnexinV positivity and elevated expression of anti-apoptosis markers, such as Bcl-2. Pro-inflammatory, TNFa and IFNy, and cytotoxicity markers, granzyme B, are increased in Cbl-b deficient CD8+ T cells. As expected from the increase of CD8+ T-cells in the aortic arch, Cbl-b-/-/ApoE-/- mice showed significantly more plaque development in the aortic root. The plaques contained higher leukocyte and T cell counts, but contained surprisingly less macrophages. The latter is caused by decreased monocyte recruitment resulting from lower MCP-1 levels. Moreover, the excess of CD8+ T cells induced enhanced cell death of macrophages. In vitro co-culture of Cbl-b deficient and wildtype CD8+ T cells with bone marrow derived macrophages revealed enhanced macrophage apoptosis in increased CD8+:macrophage ratios, irrespective of the CD8+ T cell genotype. Expression of the M1 macrophage markers, CD115 and CD64 was upregulated in Cbl-b deficient aortic arches, whereas M2 markers, CD206 and Arg-1, were decreased. In conclusion, we show that Cbl-b deficiency decreases CD4+:CD8+ T cell ratio during hypercholesterolemia, through reduced apoptosis and possibly less susceptibility of CD8+ T cells to regulatory T cell suppression. This contributes to exacerbated atherosclerosis in Cbl-b deficient mice. Although plaques contained an excess of lymphocytes and T-cells, and macrophages where of an M1 phenotype, macrophage counts were decreased. This was caused by low MCP-1 levels due to CD8+ T cell induced macrophage apoptosis. These results reveal that Cbl-b balances immune reactions in atherosclerosis.

scholarly journals 639 PIK3IP1/TrIP immune regulation on CD8+ T cells restricts anti-tumor immunity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A668-A668
Author(s):  
Benjamin Murter ◽  
Hridesh Banerjee ◽  
Andrea Szymczak-Workman ◽  
Lawrence Kane
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Immunity ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Knockout Mice ◽  
Cell Activation ◽  
Cd8 T Cell ◽  
Negative Regulator ◽  
Pi3k Signaling

BackgroundThe signaling pathways involving phosphoinositide-3-kinases (PI3Ks) are highly conserved and tightly regulated to influence the activation, proliferation, and survival of all cell types. PI3K signaling plays a major role in T cell responses to antigen due to its position directly downstream of T cell receptor (TCR)/CD28 ligation.1 2 Our lab has recently shown that the cell surface protein TrIP (Transmembrane Inhibitor of PI3K, gene name: Pik3ip1) has a distinctly high expression on T cells and is capable of downregulating PI3K signaling in CD4+ T cells, acting as a negative regulator of T cell immune responses.3 4 These studies revealed that CD4+ T cells lacking TrIP expression exhibit a more Th1 inflammatory phenotype compared to WT T cells, both in vivo and in vitro.3 These data have led us to propose that TrIP restricts the inflammatory activity of T cells more generally, including CD8+ T cells, and that targeting/knockout of this negative regulator may promote anti-tumor immunity.MethodsUsing a conditional TrIP knockout mouse model developed in our lab, we have performed syngeneic tumor challenges in CD8+ T cell-specific TrIP knockout mice (TrIPfl/flE8icre). We have also characterized the tumor immune infiltrate of these mice to understand the impact of T cell-specific TrIP deficiency on the immune landscape.ResultsOur data thus far show that CD8+ T cell-specific TrIP knockout mice (TrIPfl/flE8icre) are resistant to growth of syngeneic tumors. In addition to increased tumor resistance, we have also found that tumors harvested from our TrIPfl/flE8icre knockout mice contain twice as many infiltrating T cells compared to their WT counterparts. We also found that CD8+ T cells appeared to be the main drivers of this increased T cell infiltration, as their frequency was double that of the CD4+ population in tumors transplanted into TrIP KO mice.ConclusionsWe describe data demonstrating that TrIP, a relatively novel PI3K inhibitor, plays a significant role in the antitumor immune activity of CD8+ T cells. Our that CD8+ T cell-specific TrIP knockout mice are resistant to tumor challenge and show more robust tumor CD8+ T cell infiltrate. With these data, we are excited to propose TrIP as a potential future immunotherapeutic target worthy of continued investigation.ReferencesOkkenhaug K, Turner M, Gold MR. PI3K signaling in B cell and T cell biology. Front Immunol 2014;5:557. doi:10.3389/fimmu.2014.00557Kane LP, Weiss A. The PI-3 kinase/Akt pathway and T cell activation: pleiotropic pathways downstream of PIP3. Immunol Rev 2003;192:7–20. doi:10.1034/j.1600-065X.2003.00008.xUche UU, Piccirillo AR, Kataoka S, et al. PIK3IP1/TrIP restricts activation of T cells through inhibition of PI3K/Akt. J Exp Med 2018;215:3165–3179. doi:10.1084/jem.20172018DeFrances MC, Debelius DR, Cheng J, Kane LP. Inhibition of T-cell activation by PIK3IP1. Eur J Immunol 2012;42:2754–2759. doi:10.1002/eji.201141653

scholarly journals B7H4 expression in tumor cells impairs CD8 T cell responses and tumor immunity

2019 ◽  
Vol 69 (2) ◽  
pp. 163-174 ◽  
Author(s):  
Linlin Zhou ◽  
Mei Ruan ◽  
Ying Liu ◽  
Yanyang Zhu ◽  
Deqiang Fu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Cd8 T Cell ◽  
Negative Regulator ◽  
Cell Immune Response

AbstractB7 homolog 4 (B7H4) is considered a negative regulator of immune responses, but the immunoregulatory role of B7H4 in the tumor microenvironment is not clear. Here, we assessed B7H4 expression cell types in human breast cancer tissues and addressed its potential mechanisms in the CD8 T cell immune response. The results from flow cytometry and immunohistochemistry demonstrated that B7H4 was highly expressed in 26 out of 30 (86.7%) breast invasive ductal carcinomas, and B7H4 surface expression on tumor cells was inversely correlated with CD8 T lymphocytes infiltration (p < 0.0001). In vivo, B7H4-overexpressing tumor cells showed enhanced tumor growth in immunocompetent mice with impaired CD8 T cell infiltration of the tumor. Further investigation showed that activation and expansion of CD8 T cells within the lymph nodes were suppressed in B7H4-overexpessing tumor-bearing mice. An in vitro killing assay showed that the cytotoxicity of CD8 T cells was inhibited in B7H4-overexpressing tumor cells. These findings suggest that B7H4 in tumor cells is a negative regulator of CD8 T cell activation, expansion and cytotoxicity, indicating that tumor cell-associated B7H4 might be a target for T cell-based cancer immunotherapy.

Rap1-GTP Promotes the Generation and Effector Function of Cytotoxic CD8+ T Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3325-3325
Author(s):  
Lequn Li ◽  
Thomas Fehr ◽  
Vassiliki A. Boussiotis
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Granzyme B ◽  
Critical Role ◽  
Cytolytic Activity ◽  
Small Gtpase ◽  
Effector Function ◽  
Negative Regulator ◽  
Time Interval

Abstract Rap1, a member of the Ras superfamily, is currently emerging as a small GTPase with a critical role in cell adhesion, junction formation and spreading. In T lymphocytes, transient activation of Rap1 and accumulation of Rap1-GTP at the T cell:APCs interface is one of the physiologic consequences of TCR ligation and regulates b2 integrin activation and LFA-1:ICAM-1 mediated adhesion. To understand the role of Rap1 in the immune responses of the intact host, we generated transgenic (Tg) mice, which express the active, GTP-bound Rap1 mutant Rap1E63 in T cells. Using these mice we observed that Rap1-GTP is a negative regulator of T helper cell function and promotes the generation of CD4+CD103+ Treg cells in vivo. Here we investigated the role of Rap1 in the generation and function of cytotoxic T cells (CTL). First, we examined allogeneic responses of CD8+ T cells. Purified CD8+ T cells from either Rap1E63-Tg or normal littermate control (NLC) mice were cultured with allogeneic Balb/c splenocytes as stimulators. Proliferation of Rap1E63-Tg CD8+ T cells were reduced compared to those of NLC CD8+ cells, but reached the peak within a shorter time interval of culture. Importantly, Rap1E63 transgenic CD8+ T cells produced significantly increased levels of IFN-g compared to NLC cells. Next we examined effector function. CTL differentiation was carried out by a five-day culture of purified Rap1E63-Tg or NLC CD8+ T cells with allogeneic Balb/c splenocytes. Subsequently, effector CTL were isolated and tested for their ability to kill 51Cr-labeled P815 cells. Rap1E63-Tg effector CTL showed a 3 to 4-fold increased cytolytic activity as compared to NLC effector CTL, at all E:T cell ratios tested. Because Rap1E63 induced high levels of LFA1 activation, we examined whether LFA-1-mediated signals might be responsible for the enhanced cytolytic activity of Rap1E63-Tg CTL and whether such signals affected CTL generation or effector function. Addition of LFA-1 blocking mAb during the effector phase, abrogated CTL function in both Rap1E63 and NLC cells. Addition of LFA-1 mAb during the generation phase, did not alter CTL efficiency of NLC effectors as compared to control cultures without LFA-1. In contrast, addition of LFA1 mAb during the generation phase, dramatically reduced the enhanced killing efficiency of Rap1E63 CTL to levels comparable to NLC CTL, suggesting that Rap1-GTP predominantly regulated the generation phase of CTL effectors. Cell killing by CTL effectors requires the combined actions of the membranolytic protein perforin, and the granule-associated serine proteases, granzymes. After co-release from CTL, perforin mediates transport of granzymes, which initiate the molecular events that culminate cell death. Granzyme B, which cleaves target proteins after aspartate residues is the most efficient mediator of CTL-induced killing. Detailed analysis revealed that Rap1E63-Tg CTL effectors had significantly increased levels of perforin as determined by western blot. Granzyme B enzymatic activity was also higher in Rap1E63-Tg as compared to NLC CTL. These results indicate that Rap1-GTP promotes the generation of highly efficient CTL effectors, and at least one mechanism responsible for this effect involves the enhanced LFA-1-mediated signaling.

scholarly journals SIV-specific CD8+ T cells express high levels of PD1 and cytokines but have impaired proliferative capacity in acute and chronic SIVmac251 infection

Blood ◽  
2007 ◽  
Vol 110 (3) ◽  
pp. 928-936 ◽  
Author(s):  
Constantinos Petrovas ◽  
David A. Price ◽  
Joseph Mattapallil ◽  
David R. Ambrozak ◽  
Christof Geldmacher ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Negative Regulator ◽  
Proliferative Capacity ◽  
Primary Determinant ◽  
Differentiation Status

AbstractProgrammed death-1 (PD-1) is a critical mediator of virus-specific CD8+ T-cell exhaustion. Here, we examined the expression of PD-1 on simian immunodeficiency virus (SIV)-specific CD8+ T cells and its possible involvement in regulation of cytokine production, proliferation, and survival of these cells. The majority of SIV-specific CD8+ T cells expressed a PD-1high phenotype, independent of their differentiation status, in all tissues tested. PD-1 expression gradually declined on CD8+ T cells specific for SIV-derived epitopes that had undergone mutational escape, indicating that antigen-specific TCR stimulation is the primary determinant of PD-1 expression. SIV-specific PD-1highCD8+ T cells produced IFN-γ, TNF-α, and IL-2 under cognate peptide stimulation. While CD8+ T cells that proliferated in response to antigen had a PD-1high phenotype, it was determined that there was a reduced proliferative capacity of PD-1high compared with PD-1low SIV-specific CD8+ T cells. PD-1high SIV-specific CD8+ T cells were highly susceptible to cell death leading to loss of such cells after in vitro stimulation. Thus, PD-1 is a negative regulator of SIV-specific CD8+ T cells, operating predominantly through the induction of cell death. Manipulation of the interaction of PD-1 with its ligands could thus potentially restore the CD8+ T-cell responses in SIV infection.

scholarly journals Local antigen in nonlymphoid tissue promotes resident memory CD8+ T cell formation during viral infection

2016 ◽  
Vol 213 (6) ◽  
pp. 951-966 ◽  
Author(s):  
Tahsin N. Khan ◽  
Jana L. Mooster ◽  
Augustus M. Kilgore ◽  
Jossef F. Osborn ◽  
Jeffrey C. Nolz
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Inflammatory Responses ◽  
Critical Role ◽  
Cd8 T Cell ◽  
Dependent Manner ◽  
Independent Manner ◽  
Tissue Microenvironment ◽  
Nonlymphoid Tissue

Tissue-resident memory (Trm) CD8+ T cells are functionally distinct from their circulating counterparts and are potent mediators of host protection against reinfection. Whether local recognition of antigen in nonlymphoid tissues during infection can impact the formation of Trm populations remains unresolved. Using skin infections with vaccinia virus (VacV)–expressing model antigens, we found that local antigen recognition had a profound impact on Trm formation. Activated CD8+ T cells trafficked to VacV-infected skin in an inflammation-dependent, but antigen-independent, manner. However, after viral clearance, there was a subsequent ∼50-fold increase in Trm formation when antigen was present in the tissue microenvironment. Secondary antigen stimulation in nonlymphoid tissue caused CD8+ T cells to rapidly express CD69 and be retained at the site of infection. Finally, Trm CD8+ T cells that formed during VacV infection in an antigen-dependent manner became potent stimulators of localized antigen-specific inflammatory responses in the skin. Thus, our studies indicate that the presence of antigen in the nonlymphoid tissue microenvironment plays a critical role in the formation of functional Trm CD8+ T cell populations, a finding with relevance for both vaccine design and prevention of inflammatory disorders.

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