scholarly journals Generation of Potent Tumor-Specific CTLs from High-Dose IL-2 Activated naïve CD8 T Cells with Overcoming the Tumor-Derived Immune Suppression

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4973-4973
Author(s):  
Hong-Hanh Nguyen ◽  
Dong-hwan Kim ◽  
Hyun-Ju Lee ◽  
Sung-Hoon Jung ◽  
Hyeoung-Joon Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Telomere Length ◽  
Cd8 T Cells ◽  
Immune Suppression ◽  
Memory T Cells ◽  
High Dose ◽  
Effector Cells ◽  
Specific Ctls ◽  
Potent Tumor

Abstract (Background) Adoptive T cell therapy using tumor-infiltrating lymphocytes (TILs) is a promising treatment for cancer patients unresponsive to conventional therapies. However, clonal expansion of T cells easily faced with T cell exhaustion or terminal differentiation which related to suppression of the tumor-killing function in tumor microenvironment. Naïve CD8+T cells have an astounding capacity to react to antigens by massive expansion and differentiation into cytotoxic effector cells. However, it is the main key factor that how can increase the limited number of tumor-specific naïve CD8 T cells due to the negative selection during T cell thymic development. (Methods) In human, naïve, memory T cells and TILs were activated with CD3/CD28 dynabeads and culture on CD2-coated plate to generate various effector T cell populations (Teff N, Teff M and activated TILs). Those different effectors were analyzed the expression of surface exhaustion phenotypes, intracellular transcription factors (T-bet/Eomes) and granzyme/perforin secretions using FACS and western blot assay. Telomere length of three kinds of effector cells was analyzed. High-dose IL-2 (1ug/mL) activated naïve CD8 T cells were stimulated with tumor antigen-loaded dendritic cells (DCs) and then, ELISPOT/cytokine ELISA assay was performed to evaluate tumor-specific (TA) CTL function. In murine model, we also checked the functional difference of each effector cells as like the same methods. In addition, tumor challenging test using EG7-EL4 cell line (OVAp expression) was performed in C57BL/6 mice which adoptively transferred with OT-I thy1.1 Teff N, Teff M and activated TILs. (Results) In vitro expansion of all human naïve, memory and TIL CD8+ T cells was induced successfully. After 3-5 days of expansion, effectors from different progenitors were assessed for the several activation markers CD44, OX40 and CD27 and were considered as the CD62LlowCD44highOX40highCD27high populations. Population frequency of Teff N was significantly higher than Teff M (p < 0.05) or activated TILs (p < 0.005). Telomere length, which correlates with replicative capacity, was greatest in TeffN, shorter in TeffM and shortest in aTILs. When compared the T cell exhaustion phenotypes in three different effector cells, TeffN showed the very low expression of inhibitory markers including PD-1, CTLA-4, and KLRG-1.aTILs expressed most high exhaustion phenotypes with shorter telomere length. Moreover, the secretion of cytotoxic granules such as granzyme B and perforin gradually increased in all effector cells but, among the fully effector cells status, TeffN possess the highest expression level compared to TeffM and aTILs wheras similar level of IFN-r. To further confirm expression profile of T-box transcription factors, the expression of both T-bet and Eomes in TeffN increased at relatively early time point (D+3) and sustained high expression levels during effector status (D+5 and D+8). High expression of T-bet in TeffN promoted the full effector generation and Eomes expression linked to formation of long-term tumor-specific memory population. In CTL function, high-dose IL2-activated naïve T cells were successfully increased and generated the tumor-specific CTLs co-cultured with TA DCs, which inducing the outstanding CTL function compared to those from memory CD8 T cells or aTILs. (Discussion) High-dose IL-2 could increase the tumor-specific naïve CD8 T cells without resulting in clonal exhaustion and could generate the potent tumor-specific CTLs with overcoming the tumor-derived immune suppression compared with CD8+ TILs or secondary effectors from memory T cells. Disclosures No relevant conflicts of interest to declare.

scholarly journals Latent Membrane Protein 1 Contributes to Deficient Cellular Immunity in NKTCL Patients

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3969-3969
Author(s):  
Xiaoyan Feng ◽  
Yue Song ◽  
Zhaoming Li ◽  
Xudong Zhang ◽  
Lugui Qiu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cellular Immunity ◽  
Cd8 T Cells ◽  
T Cell Exhaustion ◽  
Immune Effector ◽  
Effector Cells ◽  
Cell Exhaustion ◽  
Specific Ctls ◽  
Immune Effector Cells

Introduction Extranodal NK/T cell lymphoma (NKTCL) is an aggressive malignance that is correlated closely with persistent Epstein-Barr virus (EBV) infection and belongs to a latency II EBV disease. Chronic persistent viral infection is known to result in T cell exhaustion, which will dramatically impede anti-tumor immunity. Delineating mechanisms of immunosuppression contributes to the development of novel immuno-therapeutically strategies. Herein, we described the immune status and possible role of latent membrane protein 1(LMP1) in NKTCL. Methods Peripheral blood mononuclear cells (PBMCs) from newly diagnosed NKTCL patients and age-matched healthy donors (HDs) were isolated and stained with surface marker or intracellular marker after permeabilization. The frequency of EBV-specific cytotoxic T cells (CTLs) was analyzed by staining with HLA-A2 tetramers assembled with synthetic peptides from LMP1. T cell proliferation was detected by dilution of stained CFSE, and apoptosis of T cells was performed via annexinV and 7-AAD dual-staining. Cytotoxicity assay of natural killer cells (NK) was measured by detecting apoptosis of CFSE-labeled K562 cells after co-culturing with PBMCs. All flow cytometry was performed by BD FACS CantoII, and analyzed with FlowJo software. Results PBMCs from 19 NKTCL patients and 18 HDs were analyzed, which showed that the patients had higher ratio of CD4+/CD8+ cells and lower frequency of CD3-CD56+NK cells, higher percentage of immunosuppressive CD4+CD25hiCD127low T regulatory cells (Tregs) and HLA-DR-CD11b+CD33+ myeloid derived suppressor cells (MDSCs). Notably, the ratio of CD8+/Tregs, a parameter representing immune effector cells status, was obviously decreased in NKTCL patients (Figure-a). Given the potential association of T cell exhaustion and NKTCL, we detected expression of T cell exhaustion markers on T cells from NKTCL patients, and found that both CD4+ and CD8+ T cells expressed much higher level of inhibitory molecules PD1, CTLA4, TIGIT and TIM3 in NKTCL patients than that of HDs (Figure-b). To further explore cellular immunity in NKTCL, T cells were divided into four subsets: CD45RA-CCR7+ central memory T cells (Tcm), CD45RA+CCR7+ terminally differentiated effector T cells (Temra), CD45RA+CCR7- naïve T cells (Tn), CD45RA-CCR7- effector memory T cells (Tem) (Figure-c). It showed that CD4+ T cells had lower Tcm, Temra and Tn but much higher proportion of Tem compared with HDs (Figure-d). Moreover, we found that expression of PD1 and CTLA4 were upregulated on all lymphocyte subsets in NKTCL patients than HDs (Figure-e). We collected additional 13 NKTCL patients and 10 HDs with positive HLA-A2 phenotype to measure percentages of EBV-specific CTLs, which showed that frequency of EBV-specific CTLs was remarkably decreased in NKTCL patients (Figure-f). In addition, EBV-specific CTLs from NKTCL patients were more likely to express higher levels of exhaustion markers but produced much less IFN-γ (Figure g-h). To explore the potent mechanism of immunosuppression in NKTCL, LMP1 attracted our attention, which had been proven capable of activating multiple signaling pathways to exert its oncogenesis function. To elucidate effect of LMP1 on immune cells, we constructed two LMP1-derived peptides and found that LMP1-derived peptides suppressed the proliferation of CD4+ and CD8+ T cells and inhibited IFN-γ production of CD8+ T cells and NK cells (Figure i-j). Meanwhile, LMP1 promoted apoptosis of both CD4+ and CD8+ T cells (Figure-k). Subsequently regulation of LMP1 on exhaustion markers of T cells were detected, which showed that PD1, CTLA4, TIGIT and TIM3 were significantly upregulated on both CD4+ and CD8+ T cells after treatment with LMP1 derived peptides (Figure-m). Furthermore, LMP1 impaired NK cytotoxicity ability, evidenced by decrease apoptosis of target cells (Figure-n). Besides its effect on immune effector cells, we also found that LMP1-expressing NKTCL cell lines obviously induced both Tregs and MDSCs after co-culture. Interestingly, the extent of induction by LMP1 of Tregs and MDSCs were in line with the expression level of LMP1 on NKTCL cells (Figure o-p). Conclusion Our study showed that LMP1 contributes to deficient cellular immunity in NKTCL patients, providing us with more insight into immunosuppressive in this entity of disease, which would lead to identification of novel treatment strategies. Figure Disclosures No relevant conflicts of interest to declare.

Role of NKG2D signaling in the cytotoxicity of activated and expanded CD8+ T cells

Blood ◽  
2004 ◽  
Vol 103 (8) ◽  
pp. 3065-3072 ◽  
Author(s):  
Michael R. Verneris ◽  
Mobin Karami ◽  
Jeanette Baker ◽  
Anishka Jayaswal ◽  
Robert S. Negrin
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Malignant Cell ◽  
Leukemic Cells ◽  
Target Cells ◽  
High Dose ◽  
Effector Cells ◽  
Nkg2d Expression

Abstract Activating and expanding T cells using T-cell receptor (TCR) cross-linking antibodies and interleukin 2 (IL-2) results in potent cytotoxic effector cells capable of recognizing a broad range of malignant cell targets, including autologous leukemic cells. The mechanism of target cell recognition has previously been unknown. Recent studies show that ligation of NKG2D on natural killer (NK) cells directly induces cytotoxicity, whereas on T cells it costimulates TCR signaling. Here we demonstrate that NKG2D expression is up-regulated upon activation and expansion of human CD8+ T cells. Antibody blocking, redirected cytolysis, and small interfering RNA (siRNA) studies using purified CD8+ T cells demonstrate that cytotoxicity against malignant target cells occurs through NKG2D-mediated recognition and signaling and not through the TCR. Activated and expanded CD8+ T cells develop cytotoxicity after 10 to 14 days of culture, coincident with the expression of the adapter protein DAP10. T cells activated and expanded in low (30 U/mL) and high (300 U/mL) concentrations of IL-2 both up-regulated NKG2D expression equally, but only cells cultured in high-dose IL-2 expressed DAP10 and were cytotoxic. Collectively these results establish that NKG2D triggering accounts for the majority of major histocompatibility complex (MHC)–unrestricted cytotoxicity of activated and expanded CD8+ T cells, likely through DAP10-mediated signaling. (Blood. 2004;103: 3065-3072)

Increases in T Cell Telomere Length in HIV Infection after Antiretroviral Combination Therapy for HIV-1 Infection Implicate Distinct Population Dynamics in CD4+ and CD8+ T Cells

1999 ◽  
Vol 92 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Sumesh Kaushal ◽  
Alan L. Landay ◽  
Michael M. Lederman ◽  
Elizabeth Connick ◽  
John Spritzler ◽  
...  
Keyword(s):  
T Cells ◽  
Population Dynamics ◽  
T Cell ◽  
Combination Therapy ◽  
Hiv Infection ◽  
Telomere Length ◽  
Cd8 T Cells ◽  
Distinct Population ◽  
Hiv 1

scholarly journals Phase 2 Study of Combination of Cytarabine, Idarubicin, and Nivolumab for Initial Therapy of Patients with Newly Diagnosed Acute Myeloid Leukemia

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 815-815
Author(s):  
Farhad Ravandi ◽  
Naval Daver ◽  
Guillermo Garcia-Manero ◽  
Christopher B Benton ◽  
Philip A Thompson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
T Cell Subsets ◽  
Newly Diagnosed ◽  
Effector Cells ◽  
T Effector Cells ◽  
Grade 3

Abstract Background: Blocking PD-1/PD-L1 pathways enhances anti-leukemia responses by enabling T-cells in murine models of AML (Zhang et al, Blood 2009). PD-1 positive CD8 T-cells are increased in bone marrow (BM) of pts with AML (Daver et al, AACR 2016). PD1 inhibition has shown activity in AML (Berger et al, Clin Cancer Res 2008). We hypothesized that addition of nivolumab to an induction regimen of ara-C and idarubicin may prolong relapse-free survival (RFS) and overall survival (OS); this study was designed to determine the feasibility of this combination. Methods: Pts with newly diagnosed acute myeloid leukemia (by WHO criteria; ≥20% blasts) and high risk MDS (≥10% blasts) were eligible to participate if they were 18-65 yrs of age and had adequate performance status (ECOG ≤3) and organ function (LVEF ≥ 50%; creatinine ≤ 1.5 g mg/dL, bilirubin ≤ 1.5 mg/dL and transaminases ≤ 2.5 times upper limit of normal). Treatment included 1 or 2 induction cycles of ara-C 1.5 g/m2 over 24 hours (days 1-4) and Idarubicin 12 mg/m2 (days 1-3). Nivolumab 3 mg/kg was started on day 24 ± 2 days and was continued every 2 weeks for up to a year. For pts achieving complete response (CR) or CR with incomplete count recovery (CRi) up to 5 consolidation cycles of attenuated dose ara-C and idarubicin was administered at approximately monthly intervals. Eligible pts received an allogeneic stem cell transplant (alloSCT) at any time during the consolidation or thereafter. Results: 3 pts with relapsed AML were treated at a run-in phase with a dose of nivolumab 1 mg/kg without specific drug-related toxicity. Subsequently, 32 pts (median age 53 yrs; range, 26-65) were treated as above including 30 with AML (24 de novo AML, 2 therapy-related AML, 3 secondary AML and 1 therapy-related secondary AML) and 2 high risk MDS. Pre-treatment genetic risk by ELN criteria was 11 adverse, 16 intermediate, and 5 favorable, including 2 FLT3 -ITD mutated, 5 NPM1 mutated, and 7 TP53 mutated. All 32 pts were evaluable for response and 23 (72%) achieved CR/CRi (19 CR, 4 CRi). The 4-week and 8 week mortality was 6% and 6%. The median number of doses of nivolumab received was 6 (range, 0-13); one pt did not receive nivolumab due to insurance issues. 9 pts underwent an alloSCT. After a median follow-up of 8.3 mths (range, 1.5-17.0) the median RFS among the responding pts has not been reached (range, 0.1 - 15.8 mths) and the median OS has not been reached (range 0.5-17.0 mths). Grade 3/4 immune mediated toxicities have been observed in 5 pts and include rash, pancreatitis, and colitis. Other grade 3/4 toxicities thought to be potentially related to nivolumab include cholecystitis in one pt. 9 pts proceeded to an alloSCT. Donor source was matched related in 2, matched unrelated in 6 and haplo-identical in 1 pt. Conditioning regimen was Fludarabine plus busulfan-based in 8, and fludarabine plus melphalan in 1 pt. 4 pts developed graft versus host disease (GVHD)(grade I/II in 3, grade III/IV in 1), which responded to treatment in 3. Multicolor flow-cytometry studies are conducted by the Immunotherapy Platform on baseline (prior to first dose of nivolumab) and on-treatment BM aspirate and peripheral blood to assess the T-cell repertoire and expression of co-stimulatory receptors and ligands on T-cell subsets and leukemic blasts, respectively. The baseline BM was evaluated on 23 of the 32 evaluable pts, including 18 responders and 5 non-responders. Pts who achieved a CR/CRi had a trend of higher frequency of live CD3+ total T cell infiltrate as compared to non-responders in the baseline BM aspirates (Fig 1A). We evaluated expression of immune markers on T cell subsets: CD4 T effector cells [Teff]: CD3+CD4+CD127lo/+Foxp3-, CD4 T regulatory cells [Treg]: CD3+CD4+CD127-Foxp3+, and CD8 T cells. At baseline, BM of non-responders had significantly higher percentage of CD4 T effector cells co-expressing the inhibitory markers PD1 and TIM3 (p&lt;0.05) and a trend towards higher percentage of CD4 T effector cells co-expressing PD1 and LAG3 compared to responders (Fig 1B). Co-expression of TIM3 or LAG3 on PD1+ T cells have been shown to be associated with an exhausted immune phenotype in AML (Zhou et al., Blood 2011). Conclusion: Addition of nivolumab to ara-C and anthracycline induction chemotherapy is feasible and safe in younger pts with AML. Among the pts proceeding to alloSCT the risk of GVHD is not significantly increased. Figure 1 Figure 1. Disclosures Daver: Pfizer Inc.: Consultancy, Research Funding; Otsuka America Pharmaceutical, Inc.: Consultancy; Sunesis Pharmaceuticals, Inc.: Consultancy, Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; Kiromic: Research Funding; Karyopharm: Consultancy, Research Funding; Jazz: Consultancy; Immunogen: Research Funding; Daiichi-Sankyo: Research Funding; Incyte Corporation: Honoraria, Research Funding. Thompson: Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jabbour: Bristol-Myers Squibb: Consultancy. Takahashi: Symbio Pharmaceuticals: Consultancy. DiNardo: Novartis: Honoraria, Research Funding; Daiichi-Sankyo: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Sharma: Jounce: Consultancy, Other: stock, Patents & Royalties: Patent licensed to Jounce; Astellas: Consultancy; EMD Serono: Consultancy; Amgen: Consultancy; Astra Zeneca: Consultancy; GSK: Consultancy; Consetellation: Other: stock; Evelo: Consultancy, Other: stock; Neon: Consultancy, Other: stock; Kite Pharma: Consultancy, Other: stock; BMS: Consultancy. Cortes: BMS: Consultancy, Research Funding; Sun Pharma: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Research Funding; ImmunoGen: Consultancy, Research Funding; ARIAD: Consultancy, Research Funding. Kantarjian: Delta-Fly Pharma: Research Funding; Amgen: Research Funding; ARIAD: Research Funding; Novartis: Research Funding; Bristol-Meyers Squibb: Research Funding; Pfizer: Research Funding.

scholarly journals CD4 T cell-intrinsic role for the T helper 17 signature cytokine IL-17: Effector resistance to immune suppression

2020 ◽  
Vol 117 (32) ◽  
pp. 19408-19414 ◽  
Author(s):  
Michael P. Crawford ◽  
Sushmita Sinha ◽  
Pranav S. Renavikar ◽  
Nicholas Borcherding ◽  
Nitin J. Karandikar
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Suppression ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
T Helper ◽  
T Helper 17 ◽  
Immune Resistance ◽  
Inflammatory Bowel

Untoward effector CD4+ T cell responses are kept in check by immune regulatory mechanisms mediated by CD4+ and CD8+ T cells. CD4+ T helper 17 (Th17) cells, characterized by IL-17 production, play important roles in the pathogenesis of autoimmune diseases (such as arthritis, multiple sclerosis, psoriasis, inflammatory bowel disease, among others) and in the host response to infection and cancer. Here, we demonstrate that human CD4+ T cells cells exposed to a Th17-differentiating milieu are significantly more resistant to immune suppression by CD8+ T cells compared to control Th0 cells. This resistance is mediated, in part, through the action of IL-17A, IL-17F, and IL-17AF heterodimer through their receptors (IL-17RA and IL-17RC) on CD4+ T cells themselves, but not through their action on CD8+ T cells or APC. We further show that IL-17 can directly act on non-Th17 effector CD4+ T cells to induce suppressive resistance, and this resistance can be reversed by blockade of IL-1β, IL-6, or STAT3. These studies reveal a role for IL-17 cytokines in mediating CD4-intrinsic immune resistance. The pathways induced in this process may serve as a critical target for future investigation and immunotherapeutic intervention.

scholarly journals Human T-cell receptor (TCR) alpha/beta + CD4-CD8- T cells express oligoclonal TCRs, share junctional motifs across TCR V beta-gene families, and phenotypically resemble memory T cells.

1993 ◽  
Vol 90 (24) ◽  
pp. 11787-11791 ◽  
Author(s):  
E. G. Brooks ◽  
S. P. Balk ◽  
K. Aupeix ◽  
M. Colonna ◽  
J. L. Strominger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd8 T Cells ◽  
Memory T Cells ◽  
Gene Families ◽  
Cell Receptor ◽  
Human T Cell ◽  
Alpha Beta ◽  
Beta Gene

scholarly journals CD40L expression permits CD8+ T cells to execute immunologic helper functions

Blood ◽  
2013 ◽  
Vol 122 (3) ◽  
pp. 405-412 ◽  
Author(s):  
Marco Frentsch ◽  
Regina Stark ◽  
Nadine Matzmohr ◽  
Sarah Meier ◽  
Sibel Durlanik ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Major Part ◽  
Memory T Cells ◽  
Helper T Cells ◽  
Key Points ◽  
Cd40l Expression ◽  
Cd8 Memory T Cells

Key Points A major part of CD8+ memory T cells expresses CD40L, the key molecule for T-cell–dependent help. CD40L-expressing CD8+ T cells resemble functional CD4+ helper T cells.

scholarly journals Impact of multiple hits with cognate antigen on memory CD8+ T-cell fate

2020 ◽  
Vol 32 (9) ◽  
pp. 571-581 ◽  
Author(s):  
Shiki Takamura
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Memory T Cells ◽  
Cd8 T Cell ◽  
T Cell Subsets ◽  
Primary Immune Response ◽  
Memory T Cell ◽  
Cognate Antigen ◽  
Memory Cd8 T Cell

Abstract Antigen-driven activation of CD8+ T cells results in the development of a robust anti-pathogen response and ultimately leads to the establishment of long-lived memory T cells. During the primary response, CD8+ T cells interact multiple times with cognate antigen on distinct types of antigen-presenting cells. The timing, location and context of these antigen encounters significantly impact the differentiation programs initiated in the cells. Moderate re-activation in the periphery promotes the establishment of the tissue-resident memory T cells that serve as sentinels at the portal of pathogen entry. Under some circumstances, moderate re-activation of T cells in the periphery can result in the excessive expansion and accumulation of circulatory memory T cells, a process called memory inflation. In contrast, excessive re-activation stimuli generally impede conventional T-cell differentiation programs and can result in T-cell exhaustion. However, these conditions can also elicit a small population of exhausted T cells with a memory-like signature and self-renewal capability that are capable of responding to immunotherapy, and restoration of functional activity. Although it is clear that antigen re-encounter during the primary immune response has a significant impact on memory T-cell development, we still do not understand the molecular details that drive these fate decisions. Here, we review our understanding of how antigen encounters and re-activation events impact the array of memory CD8+ T-cell subsets subsequently generated. Identification of the molecular programs that drive memory T-cell generation will advance the development of new vaccine strategies that elicit high-quality CD8+ T-cell memory.

Effective Deletion of Anti-Donor Host Memory Effector Cells by Anti-3rd Party Veto CTLs: Implications to Tolerance Induction in Presensitized Bone Marrow Recipients.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 44-44 ◽  
Author(s):  
Shlomit Reich-Zeliger ◽  
Esther Bachar-Lustig ◽  
Yair Reisner
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Memory T Cells ◽  
Tolerance Induction ◽  
Annexin V ◽  
Memory Cells ◽  
Spleen Cells ◽  
Memory Cd8 T Cells ◽  
Effector Cells ◽  
Veto Cells

Abstract Recently we demonstrated that veto CTLs enhance engraftment of mismatched T cell depleted BM in recipient mice following reduced intensity conditioning. This desirable tolerance induction can be further enhanced by combining veto CTLs with CD4+CD25+ cells and Rapamycin. While these results are encouraging, they were largely based on models in which the resistant effector T cells mediating the allorejection are naive CTLp. However, considering that many patients undergoing BMT are presensitized by transfusions of different blood products, memory T cells could play an important role in graft rejection and, therefore, their sensitivity to veto cells could be critical to the implementation of the latter cells in BMT. Clearly, memory T cells respond under less stringent conditions to foreign antigens, compared to their naïve counterparts. In particular, they are programmed to be activated promptly, with a reduced requirement for costimulatory signals and therefore they might be more resistant to veto cells. To address this question we used the 2C mouse model, the CD8 T cells of which express a transgenic TCR against H-2d. The CD8 T cells bearing the TCR transgene can be followed by FACS using staining with a clontypic antibody (1B2) against the transgene. In this model, addition of veto CTLs was shown to inhibit expansion of CD8+1B2+ effector cells by induction of apoptosis which can be monitored by annexin V staining. Thus, in a total of 10 experiments the addition of 5% veto cells to 3 day MLR culture of naive 2C effector cells in the presence of H-2d stimulator cells, led to 76%±9% inhibition of expansion. In order to compare the sensitivity of memory cells in the same model, memory cells were established by immunizing 2C transgenic mice with 1x106 irradiated splenocytes from Balb/c donors (H-2d origin). Six weeks later, splenocytes were harvested and after Ficoll separation were shown to be enriched with memory CD8 T cells(CD44+high CD45Rb+ CD62L+, average in 16 different experiments was 73%±11). Upon addition of 5% veto cells to MLR culture of memory 2C spleen cells in the presence of stimulator cells, 78%±7% inhibition of 2C expansion was found. This veto activity was associated with increased apoptosis of allospecific memory CD8 T cells. Thus, in the absence of veto cells the CD8+1B2+ memory cells exhibited a low level of Annexin V (6%±3%) while in the presence of 5% veto cells, a high level of Annexin V (25%±9%) was detected. The deletion of the 2C memory effectors, as previously shown for naive 2C cells, is largely dependent on the presence of Fas-FasL interaction, as indicated by using memory cells from 2C- lpr mice that lack Fas receptor on the cell surface. Upon addition of veto cells to MLR culture with 2C memory spleen cells from lpr mice, only a minor reduction of expansion (5.5%±6% in the presence of 10% veto CTLs) was detected. In conclusion, these results suggest that veto cells can delete memory effector cells as efficiently as exhibited on naive effector cells and by a similar Fas-FasL dependent mechanism. This finding might have significant implications not only for BMT, but also for the treatment of autoimmune diseases in which memory T cells play a major role.

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.

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