In CLL, Myeloid-Derived Suppressor Cells and Their Monocytic and Granulocytic Varieties Differ in T-Cell Subset Association and Polarization Induction

Abstract In chronic lymphocytic leukemia (CLL) monoclonal B cells expand and progressively accumulate in the bone marrow, eventually migrating to secondary lymphoid organs for even greater proliferation. At both sites, CLL cells engage in complex, incompletely defined cellular and molecular interactions involving multiple cell types such as T cells, myeloid cells, mesenchymal stromal cells, and matrix, collectively referred to as the "tumor microenvironment". This microenvironment is critical for the survival and proliferation of CLL cells, and data indicate that T cells and myeloid cells have an important role in these processes. In this study, we focus on two cells types: CD4+ T lymphocytes and myeloid-derived suppressor cells (MDSCs). In CLL patients, these populations are altered and impact on clinical outcome. CD4+ T cells comprise several subtypes, and CLL patients often have expanded Th2 and Tregs populations, consistent with the immunosuppressive status of these patients. Moreover, patients with higher numbers of another CD4+ subset, Th17 cells that produce IL-17 and other pro-inflammatory cytokines, can have longer survival times. Although studied minimally in CLL, MDSCs are known suppressors of T cell proliferation in vitro, and expand along with malignant cells in several cancers. However, no information is available about their effects on CD4+ T cell differentiation or on B-cell biology in CLL. In a cohort of 56 untreated CLL patients, we first explored correlation of the numbers of MDSCs and autologous T cells, using flow cytometry. CD3+ cell numbers significantly paralleled total MDSCs and monocyte-like MDSCs (mMDSCs) (P = 0.002, Spearman r = 0.44; P = 0.004, Spearman r = 0.41, respectively). Interestingly, MDSCs correlated with CD4+ and CD8+ T-cells (P < 0.001, Spearman r = 0.646; P < 0.001, Spearman r = 0.61, respectively). However, the correlation of MDSC subpopulations with CD4+ and CD8+ cells differed: mMDSCs associated significantly with CD4+ cells (P < 0.001, Spearman r = 0.73) and granulocyte-like MDSCs (gMDSCs) with CD8+ cells (P= 0.008; Spearman r = 0.45). Furthermore, although gMDSCs did not correlate with the numbers of CD4+ T-cells, we observed that they positively paralleled Tregs defined as CD3+/CD4+/CD25+/CD127-/FoxP3+ cells (P = 0.020, Spearman r = 0.44). Other subpopulations are currently under study. To address the effect of MDSCs on CD4+ cell differentiation, we FACS sorted CD3+/CD45RO- naïve CD4+ lymphocytes and stimulated them in vitro with anti-CD3/CD28 beads and IL2 in the presence or absence of mMDSCs (HLA-DRlo/CD11b+/CD33+/CD14+), gMDSCs (HLA-DRlo/CD11b+/CD33+/CD15+) or monocytes (HLA-DRhi/CD11b+/CD14+); these studies involved samples from 3 CLLs and 3 healthy controls (HCs). On day 7, cells were harvested and cytokine production was quantified by intracellular flow cytometry as the percentages of the following populations: Th1 (INFγ), Th2 (IL-4), Tregs (FoxP3), Th17 (IL-17A and IL-17F), Th9 (IL-9) and Th22 (IL-22). Culturing CLL or HC T cells in the absence of MDSCs revealed a lower percentage of cytokine-producing cells (24% vs. 55%; P = 0.017) in CLL, which was mainly due to a reduction in IL-4+ cells (P = 0.066). However, when analyzing the effects of MDSC subsets on the polarization of CLL or HC T cell, gMDSCs promoted significantly more FoxP3+ and less IL-22+ cells in CLL than in HC (P = 0.025 and P = 0.048, respectively). When analyzing only CLL T cells, supplementation with mMDSCs induced a reduction in IL-22+ cells (P = 0.027) and an insignificant increase of IL-4+ and IL-17+ cells. Conversely monocytes supported an expansion of INFγ+ T-cells (P=0.066), and gMDSCS promoted an increase of IL-9+ cells (P = 0.046) and a reduction of FoxP3+ cells (P = 0.019). In summary, in CLL the absolute numbers of total MDSCs and T cells are tightly linked. There is a significant correlation between CD4+ T cells and mMDSCs, and between CD8+ T cells and gMDSCs. Additionally, in CLL naïve CD4+ differentiation appears reduced compared to HC, in concordance with lower T-cell responses previously reported. Moreover, the preliminary aspects of the study suggest that CLL mMDSCs promote an expansion of Th2, Th17 cells and a reduction of Th22 cells, and monocytes enhance Th1s. Unexpectedly, since we observed a significant positive correlation in the PBMCs, gMDSCs may reduce Tregs and augment Th9. These findings depict differential consequences of CLL T cell - MDSC / mMDSC / gMDSC interactions. Disclosures Stamatopoulos: Abbvie: Honoraria, Other: Travel expenses; Gilead: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Other: Travel expenses, Research Funding.

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Critical and Opposing Effects of T Cell-Derived TNFα and Interferon-γ on IL-17 Induction Assessed in Vitro and in Vivo Following Allogeneic Bone Marrow Transplantation

Blood ◽

10.1182/blood.v112.11.3482.3482 ◽

2008 ◽

Vol 112 (11) ◽

pp. 3482-3482

Author(s):

Minghui Li ◽

Kai Sun ◽

Mark Hubbard ◽

Doug Redelman ◽

Angela Panoskaltsis-Mortari ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Th17 Cells ◽

Allogeneic Bone Marrow Transplantation ◽

Allogeneic Bone ◽

Allogeneic Bmt

Abstract IL-17-producing CD4 T cells (Th17) are a recently identified T helper subset that plays a role in mediating host defense to extracellular bacteria infections and is involved in the pathogenesis of many autoimmune diseases. In vitro induction of IL-17 in murine CD4+ T cells has been shown to be dependent on the presence of the proinflammatory cytokines TGF-β and IL-6 whereas IFNγ can suppress the development of Th17 cells. In the current study, we examined the roles of TNFα and IFNγ on IL-17 production by purified T cells in vitro and in vivo after allogeneic bone marrow transplantation (BMT). We present findings that expression of TNFα by the T cell itself is necessary for optimal development of Th17 under in vitro polarizing conditions. A novel role for T cell-derived TNFα in Th17 induction was observed when in vitro polarization of Tnf−/−CD4+ T cells resulted in marked reductions in IL-17+CD4+ T cells compared to Tnf+/+CD4+ T cells. In marked contrast, T cell-derived IFNγ markedly inhibited Th17 development as more IL-17+CD4+ T cells were found in Ifnγ−/−CD4+ T cells than in Ifnγ+/+CD4+ T cells, and of particular interest was the dramatic increase in IL-17+CD8+ cells from Ifnγ−/− mice. To determine if T cell-derived TNFα or IFNγ can regulate Th17 development in vivo we examined the differentiation of alloreactive donor T cells following allogeneic BMT. We have found that donor-derived Th17 cells can be found in lymphoid tissues and GVHD-affected organs after allogeneic BMT. However, transfer of Tnf−/− CD4+ T cells after allogeneic BMT resulted in marked reductions in Th17 cells in the spleen (18×103 vs 7×103, P<0.05). In agreement with the in vitro data and in contrast to what was observed with transfer of Tnf−/− CD4+ T cells, transfer of donor Ifnγ−/− T cells resulted in marked increases in not only IL-17+CD4+ but also IL-17+CD8+ T cells infiltrating the liver (7×103 vs 14×103, P<0.05; 4×104 vs 12.5×104, P<0.05). These results suggest that the donor T cell-derived TNFα and IFNγ opposingly regulate IL-17 induction of both CD4+ and CD8+ T cells in vitro and after allogeneic BMT which correlates with GVHD pathology.

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Dasatinib-Induced Reduction of Tumor Growth Is Accompanied By the Changes in the Immune Profile in a Melanoma B16.OVA Mouse Model

Blood ◽

10.1182/blood.v124.21.1408.1408 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1408-1408

Author(s):

Mette Matilda Ilander ◽

Can Hekim ◽

Markus Vähä-Koskela ◽

Paula Savola ◽

Siri Tähtinen ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Growth ◽

Cd8 T Cells ◽

Research Funding ◽

K562 Cells ◽

Cell Cytotoxicity ◽

Cd8 Cells

Abstract Background: Dasatinib is a 2nd generation tyrosine kinase inhibitor (TKI) used in the treatment of chronic myeloid leukemia (CML). Its kinase inhibition profile is broad and includes several kinases important in the immune cell function such as SRC kinases. Furthermore, it is known that dasatinib has immunomodulatory effects in vivo. Recently, we observed that dasatinib induces a rapid and marked mobilization of lymphocytes, which closely follows the drug plasma concentration. The phenomenon is accompanied by an increase of NK-cell cytotoxicity. In addition, we have shown that dasatinib alters T-cell responses long-term favoring Th1 type of responses. Interestingly, the dasatinib induced immune effects have been associated with better treatment responses. We now aimed to characterize the dasatinib-induced antitumor immune responses in a syngeneic murine melanoma model to address whether dasatinib-induced immunoactivation affects tumor growth. Methods: Direct cytotoxic effect of dasatinib on B16.OVA melanoma cells in vitro was assessed with an MTS cell viability assay. T-cell cytotoxicity was assessed by preincubating splenocytes isolated from naïve and OT-I mouse spleen with 100 nM dasatinib and measured their cytotoxic capacity against B16.OVA cells. To further evaluate the dasatinib induced antitumor immune effects in vivo, B16.OVA cells were implanted subcutaneously in C57BL/6J mice. The mice (n=6/group) were treated daily i.g. either with 30 mg/kg dasatinib or vehicle only. Blood was collected before tumor transplantation, before treatment, and on treatment days 4, 7 and 11. Tumor volumes were measured manually and specific growth rate was calculated based on the first and the last day of the treatment. In addition to white blood cell differential counts, immunophenotyping of blood and tumor homogenate was performed by flow cytometry using antibodies against CD45.1, CD3, CD4, CD8b, NK1.1, CTLA4, PD-1 and CD107. Immunohistochemical staining of CD8+ T-cells was performed from the paraffin embedded tumor samples. Results: In vitro incubation of B16.OVA cells with dasatinib showed only a moderate unspecific cytotoxicity with the two highest concentrations of dasatinib (1- and 10 µM), whereas in K562 cells (a CML blast crisis cell line) almost complete killing was observed already with the 100nM concentration. The cell viability of B16.OVA cells was 90% with at 100 nM of dasatinib concentration (as compared to 21% of K562 cells) suggesting that there was no direct dasatinib sensitive target oncokinase in this cell line. In contrast, a significant enhancement in the cytotoxic capacity of splenocytes was observed when they were pretreated with 100nM dasatinib (60% of target cells were alive when incubated with dasatinib pretreated naïve splenocytes compared to 100% with control treated splenocytes, p=0.004). The in vivo tumor experiments demonstrated that the tumor volumes were smaller in dasatinib group, and there was a significant decrease in the specific tumor growth rate (0.06 vs. 0.18, p=0.01) on the 11th day of treatment. Interestingly, dasatinib treated mice had increased proportion of CD8+cells in the circulation (17.9% vs. 14.4%, p=0.005) and the CD4/CD8 ratio was significantly decreased (1.39 vs. 1.52, p= 0.04). During the tumor growth the mean CTLA-4 expression on CD8+ cells in PB increased from 1.2% to 9% in the control group, whereas, in dasatinib group the increase was more modest (1.2% to 5.7%). When the tumor content was analyzed, dasatinib treated mice had significantly more tumor infiltrated CD8+ T-cells (median 17 vs. 4/counted fields, p=0.03). In dasatinib group 80% of the tumor infiltrating CD8+ cells expressed PD-1 antigen compared to <5% of PD1 positive CD8+ cells in the peripheral blood suggesting either tumor induced CD8 T-cell exhaustion or the presence of tumor-reactive effector cells. Lastly, when CD4 and CD8 cells were depleted before tumor inoculation, dasatinib was no longer able to slow down the tumor growth. Conclusions: Dasatinib treatment slowed the tumor growth in a B16.OVA mouse model. The growth retardation was due to immunomodulatory properties of dasatinib as the drug was not directly cytotoxic and depletion of T-cells abolished the effect. Dasatinib may be a therapeutically useful immunomodulatory agent for targeting tumor-associated anergy, particularly in combination with novel checkpoint inhibitors and tumor-targeting drugs. Disclosures Hemminki: Oncos Therapeutics Ltd: Shareholder Other; TILT BioTherapeutics Ltd: Employment, Shareholder, Shareholder Other. Porkka:BMS and Novartis: Honoraria, Research Funding; Pfizer: Research Funding. Mustjoki:Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.

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Pparα Ablation Suppresses T Cell Responses and Anti-Tumor Immunity By Compromising the Antigen-Presenting Properties of Tumor-Associated Macrophages

Blood ◽

10.1182/blood-2021-149071 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 438-438

Author(s):

Anthos Christofides ◽

Carol Cao ◽

Qi Wang ◽

Natalia M Tijaro-Ovalle ◽

Eirini Konstantinidou ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Suppressor Cells ◽

T Cell Responses ◽

Innate Immune ◽

Myeloid Derived Suppressor Cells ◽

Cell Responses

Abstract Peroxisome proliferator activated receptors (PPARs) are transcription factors that belong to nuclear hormone superfamily, with three distinct types identified: PPARapha (PPARα), PPARgamma (PPARγ), and PPARbeta/delta (PPARβ/δ). PPARs possess a critical role in the regulation of lipid metabolism, and thus play critical roles in the differentiation and fate of immune cells. PPARα is involved in lipid and carbohydrate metabolism and PPARα agonists, such as fibrates, have been used for the treatment of hypertriglyceridemia and cardiovascular diseases. PPARα has an anti-inflammatory role during infection, and similar to PPARγ, affects the polarization of macrophages. In acute myelogenous leukemia (AML), PPARα mutations correlate with chemoresistance, poor treatment outcomes and unfavorable prognosis. In experimental tumor models, it has been proposed that PPARα agonists might enhance anti-tumor T cell responses during PD-1 blocking immunotherapy. To dissect the mechanistic role of PPARα in tumor immunity, we used mice with global deletion of PPARα and examined tumor growth and profile of the immunological landscape, using various syngeneic tumor models. Significantly larger B16-F10 melanoma and MC-17 fibrosarcoma tumors were observed in PPARα KO mice compared with wild-type control, suggesting that PPARα deletion attenuated the immunological response against cancer. To dissect the role of PPARα in key populations of the innate and adaptive immune system involved in anti-tumor responses, we analyzed the immunological landscape of tumor, tumor draining lymph nodes (TDLN) and spleen, 14-16 days after tumor implantation. Assessment of CD4 + and CD8 + T cells, CD11b +F4/80 + tumor-associated macrophages (TAMs), CD11b +Ly6C hiLy6G - monocytic myeloid derived suppressor cells (M-MDSC), and CD11b +Ly6C loLy6G + polymorphonuclear myeloid derived suppressor cells (PMN-MDSC), by using flow cytometry, showed no quantitative differences between the two experimental groups. Functionally, MDSC from PPARα KO and WT mice showed comparable immunosuppressive properties as determined by suppression assay using splenocytes from OTI transgenic mice. However, PPARα KO TAMs demonstrated a less activated state, as determined by the lower expression levels of MHC-II that is critical for antigen presentation, and CD86 that is critical for T cell costimulation and prevention of T cell anergy and exhaustion. In agreement with these properties of TAMs, CD4 + T cells from TDLN of PPARα KO mice had diminished expression of activation markers, including PD-1, PD-L1 and ICOS, and numerically decreased central memory-like CD4 + T cells (T CM), compared to control tumor bearing mice. Furthermore, CD69, an emerging marker of T cell exhaustion, was significantly upregulated in CD4 + and CD8 + T cells from the TDLN of PPARα KO mice. To determine whether PPARα ablation altered the cell intrinsic properties of myeloid cells and/or T cells resulting in impaired anti-tumor function, we examined in vitro responses of isolated populations. In response to activation via TCR/CD3 and CD28, PPARα deficient T cells had no significant differences in expansion and cytokine production compared to control. In contrast, PPARα deficient Ly6C + monocytes isolated from the bone marrow displayed diminished responses to TLR-mediated signaling as determined by production of IL-6 and TNFα. Our in vitro and in vivo findings reveal a dominant role of PPARα in regulating the fate of innate immune cells thereby altering T cell responses and anti-tumor function. Our findings have implications for the development of new therapeutic approaches to enhance innate immune cell function for the improvement of cancer immunotherapy. Disclosures No relevant conflicts of interest to declare.

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T Cells from Chronic Lymphocytic Leukemia (CLL) Patients Display Dysregulated Expression of Immune Checkpoint Molecules and Activation Markers Mainly Restricted to CD4+ Cells and Correlated with Disease Activity

Blood ◽

10.1182/blood.v126.23.4132.4132 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4132-4132

Author(s):

Marzia Palma ◽

Giusy Gentilcore ◽

Fariba Mozaffari ◽

Kia Heimersson ◽

Barbro Näsman-Glaser ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Immune Checkpoint ◽

Cd4 T Cells ◽

Research Funding ◽

Immune Checkpoints ◽

Activated T Cells ◽

Activation Markers ◽

Cd8 Cells

Abstract Background CLL patients (pts) have impaired humoral and cellular immune functions, which is largely due to profound defects of T-cells. Regulation and activation of T lymphocytes depend not only on T cell receptor signaling but also on co-signaling receptors delivering either inhibitory or stimulatory signals, known as immune checkpoints. CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) is transiently expressed on activated T cells, binding the same ligands as CD28, inhibiting T-cell activation. Similarly, programmed cell death protein 1 (PD-1) is expressed on activated CD4+ and CD8+ T cells inhibiting T-cell functions upon binding to the ligands B7-H1 (PD-L1, CD274) and B7-DC (PD-L2, CD273). CD137 is an inducible costimulatory receptor expressed by activated T cells. Dysregulated expression of immune checkpoint receptors on T cells of CLL pts may have an impact on T-cell responsiveness and might be a mechanism for the immune deficiency in the disease. Aim To evaluate the expression of the immune checkpoint molecules CTLA-4, PD-1 and CD137 as well as of the cell proliferation marker Ki67, the activation marker CD69 and of CD103, a marker expressed on regulatory T cells, in T cells from CLL pts in different disease phases. Methods Peripheral blood samples were obtained from 69 CLL pts and 13 healthy control donors (HD). Pts were sub-grouped according to disease phase: indolent vs progressive (i.e. fulfilling criteria for active disease). The expression of CTLA-4, PD-1, PD-L1, CD69, CD103, CD137 and Ki-67 was assessed by flow-cytometry on CD4+ and CD8+ T cells. We also analysed the change in expression of these markers on T cells after 72 hours of PHA stimulation. Results CLL pts (n=17) had a significanty higher percentage of proliferating (Ki67+) CD3+ cells compared to HD (n=7) (median 3.7% in progressive vs 1.7% in indolent CLL vs 0.9% in HD, p=0.004 and p=0.04, respectively) (Fig.1). Progressive CLL pts had a significantly higher percentage Ki67+ CD4+ compared to indolent pts as well as HD (p=0.007 and p=0.001, respectively). Both indolent and progressive pts had higher percentage of Ki67+ CD8+ T cells compared to HD (p=0.01 and p=0.03, respectively). The percentage of CTLA-4+ CD4+ and CTLA-4+ CD8+ cells was low in CLL pts as well as in HD. However, the percentage of PD-1+ CD4+ T cells was significantly higher in progressive (n=32) as compared to indolent (n=35) CLL pts (median 40.3% vs 23.3%, p<0.0001) and HD (n=13) (median 21.5%, p<0.0001) (Fig.2) and correlated positively to the white blood cell counts (WBC) at the time of testing (r=0.29, p=0.03), while no difference was found with regard to the percentage of PD-1+ CD8+ T cells. No difference was observed between CLL pts and HD regarding the expression of PD-L1 on T cells. Both the percentage of CD69+ CD4+ and CD137+ CD4+ T cells were significantly higher in progressive as compared to indolent disease and correlated positively to WBC while no difference was found seen in CD8+ T cells. The percentage of CD103+ T cells was significantly lower in progressive compared to and HD within both the CD4+ (p=0.02) and the CD8+ subpopulations (p=0.02). After 72-hrs of PHA stimulation, PD-1 and CTLA-4 expression increased in CD4+ and CD8+ cells to a similar extent in CLL pts and HD, while PD-L1 increased in HD but not in progressive CLL pts (p=0.03 and p=0.007 for CD4+ and CD8+ cells, respectively). CD69 expression increased to a similar extent in CLL pts and HD, while CD137 expression increased more in T cells from progressive pts compared to HD (p=0.03 and 0.01 for the CD4+ and CD8+ cells, respectively). No increase in CD103 on CD8+ T-cells was observed in CLL pts compared to HD (p=0.04 and p=0.01 for the indolent and progressive pts, respectively). Conclusions Progressive CLL pts have more proliferating (Ki67+) T cells in both the CD4+ and CD8+ compartments compared to HD. CD4+ T-cells in progressive CLL pts display an activated phenotype (CD69+) and express the immune co-stimulatory molecule CD137 at a significantly higher level compared to indolent pts and HD. Nevertheless, the expression of the inhibitory immune checkpoint molecule PD-1 is so high that it is reasonable to assume that these cells are heavily impaired in their immune functions. The differences observed in the expression of immune checkpoints and activation markers between CLL pts in different phases of the disease suggest that major changes occur in the CD4+ T-cell compartment during disease progression. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Hansson: Jansse Cilag: Research Funding. Österborg:Janssen, Pharmacyclics, Gilead: Consultancy, Research Funding; Novartis: Research Funding.

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The Absence of NLRP6 in Donor T Cells Exacerbates Gvhd

Blood ◽

10.1182/blood-2021-152089 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2766-2766

Author(s):

Masahiro Suto ◽

Eri Matsuki ◽

Masahiro Miyata ◽

Erika Sekiguchi ◽

Hiroya Tamaki ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Research Funding ◽

Cell Responses ◽

Donor T Cells ◽

Induced Apoptosis

Abstract The Nlrp6 (NOD-like receptor family pyrin domain containing 6) inflammasome is important for intestinal epithelial cell innate immune responses and for maintaining gut homeostasis by preventing microbial dysbiosis. Contrary to its role in epithelial cell inflammasome-mediated responses, we recently showed that Nlrp6 in gut epithelial cells exacerbates GVHD in a manner independent of the inflammasome or gut microbiota. However, donor allogeneic T cells are also critical for GVHD development, yet, the function of Nlrp6 in allogeneic T cells is unknown. We hypothesized that Nlrp6 deficient donor T cells would ameliorate experimental GVHD. To test our hypothesis, WT-BALB/crecipients were lethally irradiated and transplanted on day 0 with 5x10 6 bone marrow and 1.0x10 6 splenic CD90 +T cells from either syngeneic WT-BALB/c, allogeneic MHC-mismatched WT-B6 or Nlrp6 -/- donors. Contrary to our hypothesis, the survival of allogeneic recipients of Nlrp6 -/- donor T cells was significantly worse than those receiving WT-B6 T cells (p<0.05). Nlrp6 -/- donor T cells also caused greater GVHD mortality and morbidity in an MHC mismatched haploidentical B6 into B6D2F1 model (p<0.05) and an MHC mismatched B10.BR into B6 model. Similar results were obtained using B6 into BALB/c and B6 into B6D2F1 models performed at the University of Michigan, suggesting our results were not unique to local environmental factors. By contrast, GVHD severity and mortality were similar in an MHC matched multiple minor antigen mismatched B6 into C3H.sw model. Because the B6 into C3H.sw model is largely driven by CD8+ T cells whereas the previous models are mediated by both CD4+ and CD8+ T cells, we examined whether Nlrp6 separately regulates CD4+ and CD8+ T cell-mediated GVHD. In order to test this, we transplanted C3H.sw recipients as above except we infused either 1x10 6 CD4+ or CD8+ T cells from B6-WT or Nlrp6 -/- animals. GVHD severity and mortality (P<0.05) were enhanced only when Nlrp6 -/- CD4+ T cells were transplanted. These data suggested that Nlrp6 regulates allogeneic T cell responses in a subset-specific manner. To explore how Nlrp6 regulates intrinsic responses in donor T cell subsets, we tested naïve T cell proliferation in vitro after allogeneic or non-specific TCR stimulation. Consistent with the lack of increased GVHD induced by CD8+ Nlrp6 -/- donor T cells in the B6 into C3H.sw model, Nlrp6 -/- CD4+ but not CD8+ T cells proliferated more than WT-B6 CD4+ or CD8+ T cells, respectively, when stimulated with either anti-CD3/CD28 antibodies or lethally irradiated allogeneic antigen presenting cells in a mixed lymphocyte reaction. In addition, activation-induced apoptosis was decreased in Nlrp6 -/- CD4+ T cells compared to WT T cells. Importantly, Treg suppressive function was not altered in Nlrp6 -/- T cells. Therefore, increased proliferative responses and resistance to activation-induced apoptosis may have contributed to the enhanced GVHD caused by Nlrp6 -/- donor T cells. Increased Th1 and Th17 polarization is associated with worse GVHD. Because only CD4+ Nlrp6 -/- T cells enhanced GVHD, we tested whether Nlrp6 influenced T helper cell differentiation into Th1, Th17, and Th2 subsets. Consistent with our in vivo data, Th1 in vitro differentiation was enhanced in Nlrp6 -/- CD4+ T cells. To determine the molecular signaling events altered by Nlrp6 deficiency, we tested various T cell activation signaling pathways and found that phosphorylation of ZAP-70 was increased in Nlrp6 -/- T cells. These data suggested that Nlrp6 in donor T cells may regulate allo-immune responses via ZAP-70 pathway. GVH and graft-versus-tumor (GVT) responses are intricately linked. Because CD8+ responses were not affected by Nlrp6 deficiency, we hypothesized that GVT responses would be unaltered in Nlrp6 -/- donor T cells. Indeed, Nlrp6 -/- T cells showed equivalent in vivo GVL responses to MLL-AF4 leukemia cells as WT-T cells. Hence Nlrp6in donor T cells is not required for GVT responses. Altogether our data suggested that Nlrp6 negatively-regulates allogeneic donor CD4+ T cell responses, possibly via negative regulation of ZAP-70 signaling, resulting in mitigation of GVHD and maintenance of robust GVT responses. Disclosures Ishizawa: AbbVie: Research Funding; Eisai: Honoraria; Chugai: Honoraria; Ono: Honoraria; Celgene: Honoraria; Takeda: Honoraria; Bayer: Research Funding; Bristol Myers Squibb: Speakers Bureau; Pfizer: Research Funding; Kyowa Kirin: Consultancy; SymBio: Honoraria, Research Funding; Otsuka: Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Sanofi: Research Funding; IQVIA: Research Funding.

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CD28 Costimulation Is Required for In Vivo Induction of Peripheral Tolerance in CD8 T Cells

Journal of Experimental Medicine ◽

10.1084/jem.20021429 ◽

2002 ◽

Vol 197 (1) ◽

pp. 19-26 ◽

Cited By ~ 27

Author(s):

Melanie S. Vacchio ◽

Richard J. Hodes

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Tolerance Induction ◽

Peripheral Tolerance ◽

Cd8 Cells ◽

Costimulatory Signal ◽

Cd28 Costimulation

Whereas ligation of CD28 is known to provide a critical costimulatory signal for activation of CD4 T cells, the requirement for CD28 as a costimulatory signal during activation of CD8 cells is less well defined. Even less is known about the involvement of CD28 signals during peripheral tolerance induction in CD8 T cells. In this study, comparison of T cell responses from CD28-deficient and CD28 wild-type H-Y–specific T cell receptor transgenic mice reveals that CD8 cells can proliferate, secrete cytokines, and generate cytotoxic T lymphocytes efficiently in the absence of CD28 costimulation in vitro. Surprisingly, using pregnancy as a model to study the H-Y–specific response of maternal T cells in the presence or absence of CD28 costimulation in vivo, it was found that peripheral tolerance does not occur in CD28KO pregnants in contrast to the partial clonal deletion and hyporesponsiveness of remaining T cells observed in CD28WT pregnants. These data demonstrate for the first time that CD28 is critical for tolerance induction of CD8 T cells, contrasting markedly with CD28 independence of in vitro activation, and suggest that the role of CD28/B7 interactions in peripheral tolerance of CD8 T cells may differ significantly from that of CD4 T cells.

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BK Polyomavirus–Specific CD8 T-Cell Expansion In Vitro Using 27mer Peptide Antigens for Developing Adoptive T-Cell Transfer and Vaccination

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa546 ◽

2020 ◽

Cited By ~ 1

Author(s):

Maud Wilhelm ◽

Amandeep Kaur ◽

Marion Wernli ◽

Hans H Hirsch

Keyword(s):

T Cells ◽

T Cell ◽

Kidney Transplant ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

T Cell Responses ◽

Cd8 T Cell ◽

Cell Responses ◽

Bk Polyomavirus

Abstract Background BK polyomavirus (BKPyV) remains a significant cause of premature kidney transplant failure. In the absence of effective antivirals, current treatments rely on reducing immunosuppression to regain immune control over BKPyV replication. Increasing BKPyV-specific CD8 T cells correlate with clearance of BKPyV DNAemia in kidney transplant patients. We characterized a novel approach for expanding BKPyV-specific CD8 T cells in vitro using 27mer-long synthetic BKPyV peptides, different types of antigen-presenting cells, and CD4 T cells. Methods Langerhans cells and immature or mature monocyte-derived dendritic cells (Mo-DCs) were generated from peripheral blood mononuclear cells of healthy blood donors, pulsed with synthetic peptide pools consisting of 36 overlapping 27mers (27mP) or 180 15mers (15mP). BKPyV-specific CD8 T-cell responses were assessed by cytokine release assays using 15mP or immunodominant 9mers. Results BKPyV-specific CD8 T cells expanded using 27mP and required mature Mo-DCs (P = .0312) and CD4 T cells (P = .0156) for highest responses. The resulting BKPyV-specific CD8 T cells proliferated, secreted multiple cytokines including interferon γ and tumor necrosis factor α, and were functional (CD107a+/PD1–) and cytotoxic. Conclusions Synthetic 27mP permit expanding BKPyV-specific CD8 T-cell responses when pulsing mature Mo-DCs in presence of CD4 T cells, suggesting novel and safe approaches to vaccination and adoptive T-cell therapies for patients before and after kidney transplantation.

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Selective anergy of V beta 8+,CD4+ T cells in Staphylococcus enterotoxin B-primed mice.

Journal of Experimental Medicine ◽

10.1084/jem.172.4.1065 ◽

1990 ◽

Vol 172 (4) ◽

pp. 1065-1070 ◽

Cited By ~ 216

Author(s):

Y Kawabe ◽

A Ochi

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

T Cell Anergy ◽

Specific Cytotoxicity ◽

Enterotoxin B ◽

Staphylococcus Enterotoxin B

The cellular basis of the in vitro and in vivo T cell responses to Staphylococcus enterotoxin B (SEB) has been investigated. The proliferation and cytotoxicity of V beta 8.1,2+,CD4+ and CD8+ T cells were observed in in vitro response to SEB. In primary cytotoxicity assays, CD4+ T cells from control spleens were more active than their CD8+ counterparts, however, in cells derived from SEB-primed mice, CD8+ T cells were dominant in SEB-specific cytotoxicity. In vivo priming with SEB abrogated the response of V beta 8.1,2+,CD4+ T cells despite the fact that these cells exist in significant number. This SEB-specific anergy occurred only in V beta 8.1,2+,CD4+ T cells but not in CD8+ T cells. These findings indicate that the requirement for the induction of antigen-specific anergy is different between CD4+ and CD8+ T cells in post-thymic tolerance, and the existence of coanergic signals for the induction of T cell anergy is suggested.

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Adoptive T Cell Therapy of Human CMV Infection in Immunocompromised Hosts: In Vitro Generation of CMV-Specific T Cells from Naïve Precursors

Blood ◽

10.1182/blood.v112.11.206.206 ◽

2008 ◽

Vol 112 (11) ◽

pp. 206-206 ◽

Cited By ~ 1

Author(s):

Sonja Schmucker ◽

Mario Assenmacher ◽

Jurgen Schmitz ◽

Anne Richter

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Peptide Pool ◽

Adoptive T Cell Therapy ◽

T Cell Therapy ◽

A Cell ◽

Ifn Γ

Abstract Adoptive transfer of virus-specific T cells is a promising therapy for the treatment of infections in immunocompromised patients. Virus-specific T cells can readily be obtained from antigen-experienced, but not naïve donors. In this study we describe a cell culture system for the in vitro generation of CMV-specific T cells from naive T cells derived from CMV-seronegative donors. We isolated naïve T cells by magnetic depletion of non-T cells, CD25+ regulatory T cells, and CD45RO+ effector and memory T cells from peripheral blood mononuclear cells (PBMC) of CMV-seronegative donors. These naïve T cells were co-cultured with autologous mature monocyte-derived DC (MoDC) loaded with a pool of overlapping peptides from the CMV protein pp65. CD3-depleted autologous PBMC were used as feeder cells and CD28 antibody, IL-2, IL-7, and IL-15 were added to the culture. Already only 9–13 days after starting the priming culture, frequencies of 0.0024% and 0.009% pp65495–503/A2-tetramer+ cells among CD8+ T cells were found for 2 HLA-A2+ blood donors. In contrast pp65495–503/A2-tetramer+ T cells were not detectable when naive T cells were cultured with unpulsed MoDC. Tetramers are suitable tools for the identification of antigen-specific T cells but are restricted to single epitopes of mainly CD8+ T cells. To analyze primed CD4+ T cells as well as CD8+ T cells having specificities other than for the peptide pp65495–503, we looked for upregulation of the activation marker CD137 after a second stimulation and found increased frequencies of CD137+ CD4+ T cells as well as CD137+ CD8+ T cells in the pp65-primed cell cultures only when restimulated with the peptide pool of pp65. Because IFN-γ is important for the control of CMV infection, we studied the capability of the in vitro primed pp65-specific CD4+ and CD8+ T cells to produce this cytokine. Restimulation of the T cells with pp65 peptide pool induced IFN-γ secretion in up to 3.9% of the CD8+ T cells and up to 3.8% of the CD4+ T cells in each of six donors tested. No specific IFN-γ production was detected after restimulation with an irrelevant IE-1 peptide pool. As expected the frequency of pp65-specific T cells in the priming cultures is low. For generation of T cell lines, we magnetically enrich pp65- specific T cells according to their IFN-γ secretion using the cytokine secretion assay technology. After further cultivation for 2 weeks the antigen-specificity of the expanded T cells was again evaluated. Only if restimulated with the pp65 peptide pool 56.6% of the CD4+ T cells showed upregulated expression of the activation marker CD154 (CD40L). Cytokine analysis of the cells revealed IFN-γ production in 40.2% of the CD4+ T cells, of which 36% co-expressed IL-2, indicating the functionality of the in vitro primed and expanded T cells. In conclusion, we established a cell culture system for in vitro priming of CMV-specific CD4+ and CD8+ T cells derived from peripheral blood of donors not infected by CMV. This should extend the application of adoptive T cell therapy to patients for whom immune donors are not available.

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Functional T Cell Array Reveals Pre-Treatment Expanded Terminal Effector Memory Response Is Associated with Lenalidomide Failure in Non-Del(5q) Myelodysplastic Syndrome.

Blood ◽

10.1182/blood.v114.22.1759.1759 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1759-1759

Author(s):

P.K. Epling-Burnette ◽

JianXiang Zou ◽

Jeffrey S. Painter ◽

Dung-Tsa Chen ◽

Jimmy Fulp ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Myelodysplastic Syndrome ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Erythroid Differentiation ◽

T Cell Response ◽

Effector Memory ◽

Terminal Effector

Abstract Abstract 1759 Poster Board I-785 Lenalidomide (LEN) is a thalidomide derivative with proven efficacy for the treatment of patients with myelodysplastic syndrome (MDS). High rates of erythroid and cytogenetic response in patients with chromosome 5q deletion [del(5q)] produced the first FDA-approved karyotype-specific treatment for this disease. Transfusion-independence rates of approximately 25% have been reported previously for patients with non-[del(5q)] and efficacy in this population has been linked to the promotion of erythroid differentiation. Because impaired erythroid differentiation in lower-risk MDS may occur through several pathophysiological mechanisms, the identification of additional factors with predictive value for both response and failure to LEN are needed to optimize success of treatment. In addition to affecting erythroid differentiation, LEN has well-known potential for immune modulation and generates highly potent effector T cell responses in vitro and in vivo by potentiating T cell receptor signaling. Immune deregulation mediated by autoreactive effector T cells has been linked to impaired erythropoiesis and granulopoiesis in a distinct subset of MDS patients raising the question of whether LEN impacts the disease process in this subset of patients. To understand the relationship between T cell deregulation and LEN response, we conducted a pilot study of 13 low/INT-1-risk non-del (5q) MDS patients (7 responders and 6 non-responders) treated with LEN and determined 23 covariates related to functional T cell response measured prior to treatment and then correlated to treatment outcome. Of these 23 covariates, multiple T cell immune parameters were analyzed but were not associated with response including interferon-g (IFNg) production by CD4+ T cells (p=0.9) and CD8+ T cells (p=0.27), Tumor Necrosis Factor (TNF)-a production by CD4+ T cells (p=1.0) and CD8+ T cells (p=0.8), TCR-associated proliferation within the CD4+ (p=1.0) and CD8+ (p=0.4) compartment, CD4/CD8 ratio (p=0.3), percentage of CD4+ (p=0.5) and CD8+ (p=0.5) T lymphocytes, and the percentage of naïve and three different types of memory CD4+ T cells. Analysis was performed using two-group comparison statistical tests (two-sample t-test and Wilcoxon rank sum test) to compare responders (R) vs non-responders (NR). Only one factor was independently linked to LEN response. Results showed that a higher percentage of CD8 T cells (mean 56% in NR vs 32% in R) with a Terminal Effector Memory [TEM]) phenotype (CD45RA+/CD62L-) was associated with LEN failure (p=0.02). This population of T cells occurs at a low frequency in healthy individuals but can be induced to differentiate in vitro under constant exposure to long-term antigen and cytokine stimulation. We have shown previously that CD8+ TEM T cells are expanded in patients with impaired myelopoiesis due to immune dysregulation in Large Granular Lymphocyte (LGL) leukemia. In conclusion, these results suggest that CD8+ terminal effector memory expansion may be linked to immune deregulation in MDS and represents an important biomarker with negative predictive importance for LEN response in non-del(5q) low-risk MDS. Disclosures No relevant conflicts of interest to declare.

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