Lack of IL-21 Signal Attenuates Graft-Versus-Leukemia Effect In the Absence of CD8 T-Cells.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3739-3739
Author(s):  
Katsutoshi Ozaki ◽  
Akiko Meguro ◽  
Keiko Hatanaka ◽  
Iekuni Oh ◽  
Haruko Matsu ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Line ◽  
Dose Reduction ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Luciferase Activity ◽  
Critical Role ◽  
Leukemic Cells ◽  
Dose Titration ◽  
Wild Type

Abstract Abstract 3739 Introduction: IL-21 is a pleiotropic cytokine belongs to a common cytokine receptor g chain family of cytokines. IL-21 is mainly produced by activated CD4+ T cells and acts on T-, B-, NK-cells, and other lineages. IL-21 can drive Th17 differentiation and contributes to the development of autoimmune disease. Previously, we have shown that IL-21R−/− (KO) splenocytes ameliorate GVHD as compared to wild type (WT) splenocytes (BMT 2010), indicating a critical role of IL-21 in GVHD. Bucher et al. reported that IL-21 neutralization resulted in the same results as ours and it did not attenuate GVL effect (Blood 2009). However, they did not titrate the required T-cells for GVL effect, making it impossible to determine if the GVL strength was similar in the normal and the IL-21 neutralized conditions. Here, we sought to quantify and compare the strength of GVL effect between WT and KO splenocytes (SP), and moreover, analyze the contributions of CD4 and CD8 cells to GVL effect. Methods: GVL experiments were performed by co-transplantation of P815 leukemic cell line, T-cell depleted wild type bone marrow cells (TCD-BM), and either KO-SP vs. WT-SP. C57BL/6-DBA F1 strain mice were used as recipients. To make the leukemia visible in alive mice, we used luciferase transduced P815 cell line and IVIS® imaging system. Results: Previously (ASH 2008), we have shown that IL-21R−/− splenocytes (KO-SP) retained GVL effect and that IL-21 decoy receptor treatment retained GVL effect. To confirm previous results, here we decided to perform dose-reduction experiment to determined the number of splenocytes required to eliminate leukemic cells after transplantation, as otherwise it is impossible to compare the strength of GVL effect between the WT and KO cells. We first started with 1 × 107 splenocytes. Without co-infusion of splenocytes, control mice died around 30–40 days after transplantation with a marked increase of luciferase activity, whereas recipients of both WT-SP and KO-SP demonstrated an eradication of P815 leukemic cells. In addition, more mice died in recipients of WT because of more severe GVHD. Secondly, we used 5 ×106 splenocytes; with this number, almost no mice died due to GVHD anymore, but still graft eradicated leukemic cells completely. Thirdly, we used 5 × 105 and 5 × 104; with these numbers, graft could not eliminate leukemic cells anymore and mice died due to leukemia. Taken together, the threshold to eradicate P815 cells in our experimental conditions was between 5 × 105 and 5 × 106 of splenocytes, regardless of genotype, WT or KO. In the experiments above with bulk splenocyte, GVL effect with KO-SP was almost comparable to that with WT-SP even throughout in the titration. However, our previous experiments demonstrated that IL-21R−/− CD4+ T-cells are defective in GVH reaction after transplantation (J Immunol. 2010). It was therefore of great interest to determine whether IL-21R−/− CD4+ T-cells are also defective in GVL effect. To evaluate the contribution of CD4+ T-cells to GVL effect, we performed transplantation with CD8-depleted splenocytes with dose-reduction as above. Because CD8 T-cells compose of only ≂f10% of splenocyte, we chose CD8-depletion rather than CD4 purification, so we could use the same dose of CD8-depleted splenocytes as in the case of bulk splenocytes. CD8-depleted KO-SP at the dose of 5 × 107 demonstrated attenuated GVHD and prolonged survival, consistent with our previous results. However, interestingly, CD8-depleted KO-SP at the dose of 5 × 106 demonstrated diminished GVL effect. Higher luciferase activity and more deaths in the KO-SP group indicated leukemic deaths. According to luciferase activity, with CD8-depleted KO-SP at the dose of 5 × 106 cells, 10 out of 21 recipients showed leukemic growth at day 21, whereas for CD8-depleted WT-SP, only 3 out of 21 mice showed leukemic growth at day 21; only 7 out of 21 mice survived in recipients of KO-SP but 13 out of 21 mice survived in recipients of WT-SP at day 100 after transplantation. Conclusion: Here we demonstrated that IL-21R−/− splenocytes (KO-SP), which ameliorate GVHD, do not attenuate GVL effect even in the splenocyte-dose-titration. In the further detailed analysis with CD8-depleted splenocytes, GVL effect with IL-21R−/− CD8-depleted splenocytes was significantly diminished compared to that with wild type, suggesting that IL-21R−/− CD4 cells have lower GVL activity than wild type cells. Disclosures: Ozawa: Nippon Shinyaku Co., Ltd.: Research Funding.

The ICOS:ICOSL Costimulatory Pathway Plays an Important Role in GVHD and Bone Marrow (BM) Graft Rejection.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 591-591 ◽  
Author(s):  
Patricia Taylor ◽  
Angela Panoskaltsis-Mortari ◽  
Gordon Freeman ◽  
Arlene Sharpe ◽  
Randolph Noelle ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Family Member ◽  
Cd8 T Cells ◽  
Graft Rejection ◽  
Cd4 T Cells ◽  
Fluorescent Protein ◽  
Wild Type ◽  
Activated T Cells ◽  
Effector Cells

Abstract ICOS, a CD28/CTLA-4 family member, is expressed on activated T cells. ICOS Ligand, a B7 family member, is constitutively expressed on B cells, monocytes and some T cells. Through the use of blocking anti-ICOS mAb and ICOS deficient (−/−) mice, we found that ICOS:ICOSL interactions play an important role in GVHD and BM graft rejection. Anti-ICOS mAb (given d-1 to d28 post BMT) significantly delayed or reduced mortality at 2 different T cell doses in a full MHC-disparate GVHD model. ICOS−/− T cells led to delayed or reduced mortality at 3 different cell doses compared to wild-type T cells. ICOS−/− CD4+ or CD8+ T cells infused into class II- or class I-disparate recipients, respectively, revealed that ICOS:ICOSL interactions regulate both CD4+ and CD8+ T cell alloresponses. Anti-ICOS inhibited GVHD in a CD28-independent fashion. Anti-ICOS inhibited GVHD mediated by either stat 4−/− or stat 6−/− T cells indicating that the ICOS pathway regulates both Th2 and Th1-mediated GVHD. In contrast to blockade of the B7:CD28/CTLA-4, CD40L:CD40 or the OX40:OX40L pathway, anti-ICOS mAb inhibited GVHD even when delayed until d5 post BMT, a time when substantial T cell expansion has occurred. A TCR transgenic model of GVHD was used to further study effects of ICOS:ICOSL blockade. All CB6 F1 recipients of anti-host alloreactive 2C CD8+ and TEa CD4+ T cells succumbed to GVHD mortality by d18 after transfer of cells. In contrast, 88% of anti-ICOS-treated mice survived long-term. Evaluation of spleens early after transplant revealed that anti-ICOS mAb reduced the number of TEa CD4+ cells by 44% and 2C CD8+ cells by 83%. Green fluorescent protein (GFP) 2C CD8+ and GFP TEa CD4+ T cells were infused into irradiated CB6 F1 mice and irrelevant or anti-ICOS mAb was administered. Mice were imaged on d4, 7 and 12 after T cell transfer. By d7, pronounced infiltration of GFP+ cells was noted in the peripheral and mesenteric LN, spleen, Peyer’s patches (PP), skin, gingiva, liver, kidney, lung, ileum, and colon of GVHD control mice. In contrast, there were fewer GFP+ cells in the spleen, ileum, colon, kidney, lung, skin and gingiva of anti-ICOS-treated mice, although there was no decrease in GFP+ cells in LNs or PP. To study the role of host ICOS expression in BM graft rejection, wild-type or ICOS−/− mice were sublethally irradiated and given allogeneic BM and evaluated for donor chimerism at 6 weeks post BMT. Five of 10 wild type mice engrafted (ave − 26% donor) in contrast to all 10 of ICOS−/− mice (ave − 71% donor). Collectively, these data indicate that ICOS:ICOSL interactions play an important role in GVHD, whether mediated by CD4+ Th1 or Th2 T cells or CD8+ T cells. Importantly, blockade of ICOS:ICOSL after initiation of alloresponses inhibited GVHD, in contrast to blockade of other costimulatory pathways, suggesting that the ICOS pathway may be a novel therapeutic target in primed transplantation situations. Anti-ICOS interfered with expansion of donor T cells in the spleen early after transplant and reduced the number of effector cells in several GVHD target tissues. These data suggest this pathway may be indicated for therapeutic targeting for the inhibition of GVHD and BM graft rejection.

WT1-Specific T Cells Exhibiting a Non-Exhausted, Functional Phenotype Can Be Generated From The Natural Repertoire Of Healthy Donors For Clinical Use

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4504-4504 ◽  
Author(s):  
Sabine Schmied ◽  
Anne Richter ◽  
Mario Assenmacher ◽  
Juergen Schmitz
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Ex Vivo ◽  
Leukemic Cells ◽  
Target Cells ◽  
Clinical Use ◽  
Healthy Donors ◽  
Effector Cytokines

Background The Wilms tumor antigen 1 (WT1) is a self-antigen expressed at high levels in leukemic cells, but not in healthy tissue. As WT1 expression in leukemic cells drives leukemogenesis, it is a favorable target antigen for immunotherapy, e.g. adoptive transfer of allogeneic T cells, to prevent or treat leukemic relapse after stem cell transplantation (Cheever et al., Clin Cancer Res 2009;15(17)). WT1-specific CD8+ T cells have been detected in healthy individuals at low frequencies (Rezvani et al., Blood 2003;102). However, a comprehensive characterization of CD4+ and CD8+WT1-specific T cells is missing and the efficient expansion of a polyclonal WT1-reactive T cell population for clinical use has remained a major challenge. In this study we aim to directly ex vivo characterize WT1-specific T cells present in the blood of healthy donors at high-resolution and to develop a rapid method for the generation of functionally potent, polyclonal CD4+ and CD8+WT1-specific T cells for clinical use. Methods For direct ex vivo analysis of CD4+ WT1-specific T cells peripheral blood mononuclear cells (PBMC) of healthy blood donors were in vitro stimulated with a pool of overlapping peptides spanning the WT1 protein for 7 hours. Subsequently CD154 (CD40L)-expressing cells were magnetically enriched and flow cytometrically examined for expression of effector cytokines and their differentiation status. Presence and phenotype of CD8+ WT1-specific T cells have been studied after stimulation of presorted naïve and memory T cell populations with WT-1 peptide pool for 30 hours, magnetic enrichment of CD137+ (4-1BB) cells and subsequent staining using pMHCI-Tetramers. For the generation of polyclonal WT1-specific CD4+ and CD8+ T cells PBMC were in vitro activated with WT-1 peptide pool for 30 hours. CD137+cells were magnetically selected and expanded for 9 days in the presence of the cytokines IL-7, IL-15 and IL-21 at low doses. Expanded T cells were analyzed for their phenotype, the expression of co-stimulatory and exhaustion markers and were tested for their functionality and cytotoxicity by restimulation experiments with antigen-loaded target cells. Results Ex vivo frequencies of WT1-specific T cells are low, 1 to 10 WT1-specific CD154+ CD4+ T cells can be detected within 1x106 CD4+ T cells. In about 80% of healthy donors (n=15) a CD4+ memory response, accompanied by production of effector cytokines like IFNγ, TNFα and IL-2, against WT1 peptides is present. Additionally, in all donors naïve WT1-specific CD4+ T cells can be detected. In contrast, detected CD137+CD8+ WT1-reactive T cells exhibit a naïve phenotype (CD45RA+CCR7+) in all donors (n=5), no WT1-reactive CD8+T cells could be enriched from presorted memory T cells. To evaluate the usefulness of our improved short-term expansion protocol to generate potent WT1-specific T cell cultures for clinical use, we characterized CD137 enriched and expanded T cells. Notably, a high frequency of CD4+ and CD8+ T cells show specific reactivity against WT1-presenting autologous cells as detected by production of effector cytokines like IFNγ, TNFα and IL-2 after antigen-specific restimulation. Cytotoxic activity against antigen-loaded target cells could be shown by direct flow-cytometry-based cytotoxicity assays and antigen-specific upregulation of the degranulation marker CD107a. Stainings using multiple WT1-MHCI-tetramers furthermore confirmed antigen-specificity and suggested polyclonality within the CD8+T cell population. In contrast to previous expansion protocols our polyclonally expanded T cells exhibit a favourable, unexhausted memory phenotype, express co-stimulatory markers CD27 and CD28 and the IL7R-a chain (CD127) which has been shown to mark cells with stem T cell like properties. Furthermore exhaustion markers like CD279 (PD-1), CD178 (FasL) and CD57 are scarcely expressed. Conclusions Functional, polyclonal, CD4+ and CD8+ WT1-specific, reactive T cells can be efficiently enriched directly ex vivo from the natural repertoire by magnetic separation of T cells after antigen-specific stimulation. Phenotypic and functional characterization revealed a non-exhausted phenotype of expanded WT1-specific T cells, thereby suggesting good persistence and functionality of the obtained T cell product in vivo. Thus, our approach holds great potential for the GMP-compliant generation of WT1-specific T cells for future clinical use. Disclosures: Schmied: Miltenyi Biotec GmbH: Employment. Richter:Miltenyi Biotec GmbH: Employment. Assenmacher:Miltenyi Biotec GmbH: Employment. Schmitz:Miltenyi Biotec: Employment.

scholarly journals CD4+ T cells sustain aggressive chronic lymphocytic leukemia in Eμ-TCL1 mice through a CD40L-independent mechanism

2021 ◽  
Vol 5 (14) ◽  
pp. 2817-2828
Author(s):  
Matteo Grioni ◽  
Arianna Brevi ◽  
Elena Cattaneo ◽  
Alessandra Rovida ◽  
Jessica Bordini ◽  
...  
Keyword(s):  
T Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Antigen Specificity

Abstract Chronic lymphocytic leukemia (CLL) is caused by the progressive accumulation of mature CD5+ B cells in secondary lymphoid organs. In vitro data suggest that CD4+ T lymphocytes also sustain survival and proliferation of CLL clones through CD40L/CD40 interactions. In vivo data in animal models are conflicting. To clarify this clinically relevant biological issue, we generated genetically modified Eμ-TCL1 mice lacking CD4+ T cells (TCL1+/+AB0), CD40 (TCL1+/+CD40−/−), or CD8+ T cells (TCL1+/+TAP−/−), and we monitored the appearance and progression of a disease that mimics aggressive human CLL by flow cytometry and immunohistochemical analyses. Findings were confirmed by adoptive transfer of leukemic cells into mice lacking CD4+ T cells or CD40L or mice treated with antibodies depleting CD4 T cells or blocking CD40L/CD40 interactions. CLL clones did not proliferate in mice lacking or depleted of CD4+ T cells, thus confirming that CD4+ T cells are essential for CLL development. By contrast, CD8+ T cells exerted an antitumor activity, as indicated by the accelerated disease progression in TCL1+/+TAP−/− mice. Antigen specificity of CD4+ T cells was marginal for CLL development, because CLL clones efficiently proliferated in transgenic mice whose CD4 T cells had a T-cell receptor with CLL-unrelated specificities. Leukemic clones also proliferated when transferred into wild-type mice treated with monoclonal antibodies blocking CD40 or into CD40L−/− mice, and TCL1+/+CD40−/− mice developed frank CLL. Our data demonstrate that CD8+ T cells restrain CLL progression, whereas CD4+ T cells support the growth of leukemic clones in TCL1 mice through CD40-independent and apparently noncognate mechanisms.

Characterization of pathogenic CD8 + T cells in Chlamydia - infected OT1 mice

2021 ◽  
Author(s):  
Zengzi Zhou ◽  
Qi Tian ◽  
Luying Wang ◽  
Xin Sun ◽  
Nu Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
Chlamydia Trachomatis ◽  
Cd8 T Cells ◽  
Chlamydial Infection ◽  
Critical Role ◽  
Wild Type ◽  
Chlamydia Muridarum ◽  
Time Of Infection

Chlamydia trachomatis is a leading infectious cause of infertility in women due to its induction of lasting pathology such as hydrosalpinx. Chlamydia muridarum induces mouse hydrosalpinx because C. muridarum can both invade tubal epithelia directly (as a 1 st hit) and induce lymphocytes to promote hydrosalpinx indirectly (as a 2 nd hit). In the current study, a critical role of CD8 + T cells in chlamydial induction of hydrosalpinx was validated in both wild type C57BL/6J and OT1 transgenic mice. OT1 mice failed to develop hydrosalpinx partially due to the failure of their lymphocytes to recognize chlamydial antigens. CD8 + T cells from naïve C57BL/6J rescued the recipient OT1 mice to develop hydrosalpinx when naïve CD8 + T cells were transferred at the time of infection with Chlamydia . However, when the transfer was delayed for 2 weeks or longer after the chlamydial infection, naïve CD8 + T cells no longer promoted hydrosalpinx. Nevertheless, Chlamydia -immunized CD8 + T cells still promoted significant hydrosalpinx in the recipient OT1 mice even when the transfer was delayed for 3 weeks. Thus, CD8 + T cells must be primed within 2 weeks after chlamydial infection to be pathogenic but once primed, they can promote hydrosalpinx for >3 weeks. However, Chlamydia -primed CD4 + T cells failed to promote chlamydial induction of pathology in OT1 mice. This study has optimized an OT1 mouse-based model for revealing the pathogenic mechanisms of Chlamydia -specific CD8 + T cells.

CD4+ Regulatory T Cells Specific for the WT1 Antigen Are Present in Acute Myeloid Leukemia Patients: Implication for Immunotherapy.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1933-1933
Author(s):  
Said Dermime ◽  
Cynthia Lehe ◽  
Hazem Ghebeh ◽  
Abdullah Al-Sulaiman ◽  
Ghofran Al Qudaihi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cytotoxic Activity ◽  
Cd8 T Cells ◽  
Ex Vivo ◽  
Granzyme B ◽  
Critical Role ◽  
Leukemic Cells ◽  
Cell Contact

Abstract Compelling evidences indicate a key role for regulatory T cells (Tregs) on the host response to cancer and recent studies indicated that the generation of effective WT1-specific cytotoxic T cells can be largely affected by the presence of Tregs. This is the first study to describe human Tregs generated specifically against the WT1 antigen which is overexpressed in several human leukemias and provide the mechanism by which these anti-WT1 Tregs inhibit the immune response in leukemia patients. We have generated T cell lines and clones that specifically recognized a WT1-84 peptide in an HLA DRB1*0402/TCR-Vb8-restricted manner. Importantly, they recognized HLADRB1* 04-matched fresh leukemic cells expressing the WT1 antigen. These clones exerted a Th2 cytokine profile, had a CD4+CD25+Foxp3+GITR+CD127− Tregs phenotype, and significantly inhibited the proliferative activity of allogeneic T cells independently of cell-contact. Priming of allo-reactive T cells in the presence of Tregs strongly inhibited the expansion of NK; NK-T and CD8+ T cells, had an inhibitory effect on NK/NK-T cytotoxic activity but not on CD8+ T cells. Furthermore, priming of T cells with the WT1- 126 HLA-A0201-restricted peptide in the presence of Tregs strongly inhibited the induction of anti-WT1-126 CD8+ CTL responses as evidenced by both very low cytotoxic activity and IFN-g production. Moreover, these Tregs clones specifically produced Granzyme-B and selectively induced apoptosis in WT1-84 pulsed-autologous APCs but not in apoptoticresistant DR4-matched leukemic cells. Importantly, we have also detected anti-WT1-84 IL-5+/Granzyme-B+/Foxp3+ CD4+ Tregs in 5 out of 8 HLA-DR4+ AML patients. These findings suggest a critical role for anti-WT1 Tregs in the inhibition of T cell responses against leukemia. This study may have important implications for the clinical manipulation of Tregs such as immuno-targeting of TCR-Vb-8 with mAbs to eliminate anti-WT1 Tregs in leukemia patients in order to enhance GVL before vaccination with the WT1 antigen. On the other hand, leukemia patients with GVHD should be clinically-tried for vaccination with the current WT1-84 peptide or adoptively-treated with ex-vivo anti-WT1 Treg cells to specifically enhance their frequency, which is known to be very low in these patients.

Abrogation of Donor T Cell IL-21 Signaling Leads to Tissue-Specific Modulation of Immunity and Separation of Gvhd From GVL

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 729-729
Author(s):  
Alan M. Hanash ◽  
Lucy W. Kappel ◽  
Nury L. Yim ◽  
Rebecca A. Nejat ◽  
Gabrielle L. Goldberg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Inflammatory Cytokine ◽  
Wild Type ◽  
Mesenteric Lymph Nodes ◽  
Mesenteric Lymph ◽  
Donor T Cells

Abstract Abstract 729 Allogeneic hematopoietic transplantation is frequently the only curative therapy available to patients with hematopoietic malignancies, however transplant success continues to be limited by complications including graft vs. host disease (GVHD) and disease relapse. Separation of GVHD from graft vs. leukemia/lymphoma (GVL) responses continues to be a major goal of experimental and clinical transplantation, and better understanding of T cell immunobiology may lead to novel strategies to accomplish this goal. Interleukin 21 (IL-21) is a pro-inflammatory cytokine produced by Th17 helper T cells, and abrogation of IL-21 signaling has recently been demonstrated to reduce GVHD while retaining GVL. However, the mechanisms by which IL-21 may lead to a separation of GVHD and GVL are incompletely understood. In order to characterize the effect of IL-21 on GVH and GVL T cell responses, we compared wild type and IL-21 receptor knockout (IL-21R KO) donor T cells in a C57BL/6 into BALB/c murine MHC-mismatched bone marrow transplant (BMT) model. Lethally irradiated BMT recipients of IL-21R KO T cells demonstrated decreased GVHD-related morbidity (p<.05) and mortality (p<.01), and decreased histopathologic evidence of GVHD within the small intestine (p<.05). While this reduction in IL-21R KO T cell-mediated GVHD was associated with increased donor regulatory T cells two to three weeks post-BMT (p<.001), IL-21 signaling in both donor CD4 and donor CD8 T cells was found to contribute to GVHD mortality (p<.01 for CD4, p<.05 for CD8). Analysis of IL-21R expression by wild type T cells demonstrated receptor upregulation upon polyclonal activation in vitro and upon alloactivation in vivo (p<.01). However, this IL-21R upregulation was not required for in vivo alloactivation, as IL-21R KO and wild type donor T cells demonstrated equivalently greater proliferation in allogeneic vs. syngeneic recipients (p<.001), equivalent upregulation of CD25 (p<.001), and equivalent downregulation of CD62L (p<.01 for CD8 T cells). Despite this equivalent alloactivation, IL-21R KO T cells demonstrated decreased infiltration within the small intestine (p<.05), decreased infiltration in mesenteric lymph nodes (p<.05 for CD8 T cells, p<.001 for CD4 T cells), and decreased inflammatory cytokine-producing CD4 T cells within mesenteric lymph nodes (p<.01 for IFN-g, p<.001 for TNF-a, Figure 1A). Consistent with this, transplanted IL-21R KO donor T cells demonstrated decreased expression of a4b7 integrin (LPAM, p<.05), a molecule known to be involved in homing of GVHD-mediating donor T cells to the gut. However, in contrast to the reduced inflammatory cytokine-producing CD4 T cells observed in mesenteric lymph nodes, IL-21R KO helper T cell cytokine production was maintained in spleen (Figure 1B) and peripheral lymph nodes, and IL-21R KO T cells were able to protect recipient mice from lethality due to A20 lymphoma (p<.001). In summary, abrogation of IL-21 signaling in donor T cells leads to tissue-specific modulation of immunity, such that gastrointestinal GVHD is reduced, but peripheral T cell function and GVL capacity are retained. Targeting IL-21 for therapeutic intervention is an exciting strategy to separate GVHD from GVL, and this novel approach should be considered for clinical investigation to improve transplant outcomes and prevent malignant relapse. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Identification of a distant T-bet enhancer responsive to IL-12/Stat4 and IFNγ/Stat1 signals

Blood ◽  
2007 ◽  
Vol 110 (7) ◽  
pp. 2494-2500 ◽  
Author(s):  
Yu Yang ◽  
Jordi C. Ochando ◽  
Jonathan S. Bromberg ◽  
Yaozhong Ding
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Reporter Gene ◽  
Cd8 T Cells ◽  
Critical Role ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Wild Type ◽  
Th1 Polarization

T-bet plays a critical role in controlling IFNγ expression, Th1 polarization, and CD8 cytolytic development. Its regulation has been demonstrated to be mostly IFNγ/Stat1 dependent while IL-12/Stat4 independent. Here we show that IL-12/Stat4 binds to a distant highly conserved STAT-responsive T-bet enhancer, and induces IFNγ/Stat1-independent T-bet expression in CD8 T cells. Luciferase reporter assay showed that both Stat4 and Stat1 activate reporter gene expression from constructs containing a wild-type but not mutated T-bet enhancer. Studies in virus-infected mice demonstrated that the IL-12/Stat4/T-bet cascade operates in vivo and regulates IFNγ in CD8 T cells. Together, we provide a novel mechanism for T-bet regulation, and suggest that IL-12/Stat4/T-bet play an important role in CD8 effector responses.

Histone Deacetylase 6 (HDAC6) Influences T-Cell Activation and Survival: Implications For Cancer Immunotherapy

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1050-1050
Author(s):  
Andressa Sodre Laino ◽  
David M Woods ◽  
Fengdong Cheng ◽  
Hongwei Wang ◽  
Eduardo M. Sotomayor
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Survival ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Wild Type ◽  
T Cell Survival

Abstract The role of histone deacetylases (HDACs) as epigenetic regulators of immune function is becoming increasingly clear. Recently, the role of specific HDACs in orchestrating T-cell maturation, survival and function has begun to emerge, giving rationale to selective therapy to direct immune responses in different disease settings, including cancer. In particular, HDAC6 has recently been characterized as a negative regulator of regulatory T-cell suppressive activity (de Zoeten, Molecular and Cellular Biology, 2011). Here we report an expanded, novel role of HDAC6 in regulating T-cell survival and activation. First, the relative expression of the eleven classic HDACs was evaluated in resting and activated T-cells from mouse and human samples. It was found that the majority of HDACs decrease in expression following activation, including HDAC6. Next, in a HDAC6KO mouse model, it was found that T-cells lacking HDAC6 had skewed survival when compared to wild-type murine T-cells. This difference seems to be the result of an increased CD4+ T-cells population in the lymph nodes, with a concomitant decrease in viable CD8+ T-cells. To determine whether this population skewing was the consequence of defects in HDAC6KO mice T-cell development, wild-type murine T-cells were treated with an isotype-selective HDAC6 inhibitor. The results seen in HDAC6KO T-cells were recapitulated when wild-type T-cells were activated and treated with HDAC6 specific inhibitors, indicating a role of HDAC6 outside of thymic development in promoting CD4+ T-cell survival at the expense of CD8+ T-cells. Interestingly, it was found that activated CD4+ T-cells displayed decreased expression of the apoptosis signaling receptor FAS after HDAC6 inhibition while no differences were observed in CD8+ T-cells under the same conditions. In addition to these results implicating HDAC6 in regulating T-cell survival, expression of surface markers was altered in both CD8+ and CD4+ T-cells, including enhanced expression of the activation molecule CD69 in stimulated T-cells treated with an isotype-selective HDAC6 inhibitor. Finally, in vivo studies in tumor-bearing HDAC6KO mice revealed a significantly delayed in tumor progression. Similar results were observed in lymphoma-bearing mice treated with HDAC6 specific inhibitors. Taken together, this data shows that HDACs are dynamic in expression with regards to T-cell activation state. More specifically, we have unveiled hereto-unexplored roles of HDAC6 in regulating T-cell survival and function, pointing at this specific HDAC as an appealing target to harness T-cell immunity in hematologic malignancies. Disclosures: No relevant conflicts of interest to declare.

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