scholarly journals Combining the Expression of CD33.CAR and CXCR4 to Increase CAR-CIK Cell Homing to Bone Marrow Niche and Leukemic Stem Cell Eradication in Acute Myeloid Leukemia

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2791-2791
Author(s):  
Marta Biondi ◽  
Beatrice Cerina ◽  
Chiara Tomasoni ◽  
Gianpietro Dotti ◽  
Sarah Tettamanti ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
Sleeping Beauty ◽  
Advisory Board ◽  
Over Expression ◽  
Car T ◽  
Acute Myeloid

Abstract Chimeric Antigen Receptor (CAR) T cell therapy is a promising treatment for acute myeloid leukemia (AML), but a limited efficacy was reported from ongoing clinical trials. The capacity of engineered T cells to infiltrate into the bone marrow (BM) niche, where leukemic stem cells (LSC) reside, strongly impacts the success of the treatment. Ex vivo manipulation of CAR T cells affects the expression of several chemokine receptors and may alter the capacity of infused cells to migrate to BM. The chemokine ligand 12 (CXCL12), released by mesenchymal stromal cells (MSCs) within the medullary niche, and its chemokine receptor 4 (CXCR4) regulate leukocytes trafficking to the BM. In AML, CXCL12 binds CXCR4 over-expressed on blasts, promoting their homing in the niche. CXCR4 expression is drastically downregulated during the culture of cytokine induced killer (CIK) cells, an interesting effector T cell population with acquired NK-like cytotoxicity along with minimal alloreactivity. Therefore, combining the expression of CD33.CAR with the over-expression of CXCR4 might facilitate CAR-CIKs homing to the BM and subsequent leukemia eradication. We designed two bicistronic Sleeping Beauty transposon vectors: CXCR4(IRES)CD33.CAR and CD33.CAR(2A)CXCR4. The monocistronic CD33.CAR was used as control. We observed that both CD33.CAR(2A)CXCR4-CIKs (n=22, P<0.0001) and CXCR4(IRES)CD33.CAR-CIKs (n=9, P<0.0001) maintained CXCR4 over-expression during culture, whereas in CD33.CAR-CIKs was drastically downregulated (n=22). However, CD33.CAR expression was lower in CXCR4(IRES)CD33.CAR-CIKs (n=8, P<0.0001) compared to CD33.CAR-CIKs, while CD33.CAR(2A)CXCR4-CIKs (n=11) exhibited a significant co-expression of both proteins against control (P=0.001). CXCR4(IRES)CD33.CAR-CIKs and CD33.CAR(2A)CXCR4-CIKs maintained all CAR-associated in vitro effector functions, eliminating CD33+ KG1 target cell line, releasing cytokines (IL-2 and IFN-γ) and proliferating in an antigen-specific manner. However, CXCR4(IRES)CD33.CAR-CIKs exhibited lower effector responses against control, due to lower CAR expression. Chemotaxis assays toward recombinant CXCL12 confirmed both CXCR4(IRES)CD33.CAR-CIKs (n=7, P=0.01) and CD33.CAR(2A)CXCR4-CIKs (n=8, P=0.0006) displayed a migration advantage over CD33.CAR-CIKs (n=12) with a mean percentage of migration of 58.5% and 67.2% respectively, compared to 40.1%. Interestingly, CD33.CAR(2A)CXCR4-CIKs (n=2) showed an increased specific chemotactic response toward healthy (n=3) and AML-derived MSC (n=2) supernatants, which could be inhibited by the use of the CXCR4 antagonist Plerixafor. Moreover, when infused intravenously into NSG mice, significantly higher proportions of CD33.CAR(2A)CXCR4-CIKs were recovered in the femur BM compared to controls (P=0.0068). In conclusion, CD33.CAR(2A)CXCR4-CIKs, reaching the medullary niche more effectively, have the potential to more efficiently target the residing LSC responsible for the high relapse rates in AML. Disclosures Dotti: Tessa Therapeutics: Consultancy; Bellicum Pharmaceuticals: Consultancy; Catamaran: Consultancy. Biondi: Bluebird: Other: Advisory Board; Amgen: Honoraria; Incyte: Consultancy, Other: Advisory Board; Novartis: Honoraria; Colmmune: Honoraria.

scholarly journals Checkpoint Blockade in Combination with CD33 Chimeric Antigen Receptor T Cell Therapy and Hypomethylating Agent Against Acute Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1383-1383 ◽  
Author(s):  
Tongyuan Xue ◽  
Marissa Del Real ◽  
Emanuela Marcucci ◽  
Candida Toribio ◽  
Sonia Maryam Setayesh ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Therapy ◽  
Programmed Death ◽  
Car T ◽  
Acute Myeloid

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. The cure rate for primary AML patients is only 35% and decreases with age. Novel and effective immunotherapies for patients with relapsed and/or refractory (r/r) AML remain an urgent unmet need. CD33 is an attractive immunotherapeutic target for myeloid malignancies given its expression on more than 85% of AML patient samples. We therefore set out to design and test CD33 chimeric antigen receptor (CD33CAR) T cells preclinically as a single agent and in combinational therapy. To assess antileukemic responses of CD33CAR T cells in vitro and in vivo, we enriched CD4/CD8 T cells from peripheral blood mononuclear cells (PBMCs) and genetically modified them to express a second-generation CD33CAR. CD33CAR T cells exhibited potent antigen dependent CD107a degranulation, IFN-γ production and killing activities against AML cells in vitro. Using a NOD-SCID-IL2Rgnull (NSG) xenograft model engrafted with MOLM-14-ffluc, a CD33 expressing AML cell line transduced with lentivirus carrying firefly luciferase (ffluc) and enhanced green fluorescent protein (eGFP), 3 million CD33CAR or mock T cells were introduced intravenously. CD33 CAR T cell-treated group displayed 98.2% leukemic regression 4 days post CAR T infusion, and 99.6% reduction on day 31. Bioluminescent imaging (BLI) and Kaplan-Meier analysis demonstrated that CD33CAR T cells significantly decreased leukemic burden and prolonged overall survival compared to mock T cells in vivo. Decitabine, a DNA hypomethylating agent (HMA), is a main therapeutic agent for treating AML. We observed HMA treatment led to increased CD33 expression on MOLM-14 cells in vitro. We hypothesized that decitabine can potentiate CD33CAR T cell-mediated AML killing by increasing CD33 expression. MOLM-14 cells were treated with either decitabine alone, CD33CAR T cells alone, or sequential treatment using various concentrations of decitabine or DMSO followed by CD33CAR or mock T cells in an E:T ratio of 1:100. We determined the target specific killing activities in each group using flow cytometric based analysis 48 and 96 hours later. The decitabine followed by CD33CAR T cells treatment reproducibly resulted in the most robust antileukemic activity with 80.6% MOLM-14 cells killed. In comparison, CD33CAR T cells or decitabine monotherapy resulted in 11.5% and 50.9% killing, respectively. In vivo testing of the combinational effects of decitabine and CD33CAR T cells are underway and will be updated at the meeting. Finally, checkpoint blockade targeting programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) has shown survival benefits, particularly in combination with HMA, for patients with r/r AML (Daver et al. 2019). We observed elevated PD-L1 expression on residual AML blasts that survived the treatment with decitabine in combination with CD33CAR T cells. Therefore, we hypothesized that blockade of PD-1/PD-L1 interaction might further improve the antileukemic effect of CD33CAR T cells against AML cells post antigen induction by decitabine. MOLM-14 cells were treated with decitabine for 2 days and CD33CAR T cells were added in an E:T ratio of 1:75. Anti-PD-1 or IgG4 antibody was added to the culture at various concentrations. The most robust CD33 specific killing was seen in the culture with anti-PD-1 antibody added. Further characterization are underway and will be presented. Taken together, our preclinical findings have demonstrated the potency of the CD33CAR T cell therapy and ways to optimize its efficacy. Our results support clinical translation of CD33CAR T cells for patients with AML. Disclosures Budde: F. Hoffmann-La Roche Ltd: Consultancy.

scholarly journals Harnessing T Cells to Target Pediatric Acute Myeloid Leukemia: CARs, BiTEs, and Beyond

Children ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 14
Author(s):  
Rebecca Epperly ◽  
Stephen Gottschalk ◽  
Mireya Paulina Velasquez
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Targeted Therapies ◽  
Myeloid Leukemia ◽  
Immune Therapy ◽  
Bispecific Antibodies ◽  
Car T Cells ◽  
Car T ◽  
Acute Myeloid

Outcomes for pediatric patients with acute myeloid leukemia (AML) remain poor, highlighting the need for improved targeted therapies. Building on the success of CD19-directed immune therapy for acute lymphocytic leukemia (ALL), efforts are ongoing to develop similar strategies for AML. Identifying target antigens for AML is challenging because of the high expression overlap in hematopoietic cells and normal tissues. Despite this, CD123 and CD33 antigen targeted therapies, among others, have emerged as promising candidates. In this review we focus on AML-specific T cell engaging bispecific antibodies and chimeric antigen receptor (CAR) T cells. We review antigens being explored for T cell-based immunotherapy in AML, describe the landscape of clinical trials upcoming for bispecific antibodies and CAR T cells, and highlight strategies to overcome additional challenges facing translation of T cell-based immunotherapy for AML.

scholarly journals Identification and Isolation of Tumor-Specific Cytotoxic T Lymphocytes in Acute Myeloid Leukemia Patients through the Identification of T-Cells Capable to Establish Stable Interactions with Leukemic Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3336-3336
Author(s):  
Estefania Garcia-Guerrero ◽  
Luis I. Sanchez-Abarca ◽  
Esther Domingo ◽  
Teresa Ramos ◽  
Jose Antonio Bejarano-García ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
T Lymphocytes ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Myeloid Leukemia ◽  
Target Cells ◽  
Acute Myeloid

Abstract Introduction Autologous adoptive T cell therapies, based on the use of tumor infiltrating lymphocytes (TILs), have made great progress in recent years for the treatment of solid tumors, especially melanoma. However, further work is needed to isolate tumor-reactive T cells among patients diagnosed with hematologic malignancies. The dynamics of the interaction between T cells and antigen presenting cells (APC) dictate the quality of the immune responses. While stable joints between target cells and T lymphocytes lead to the induction of T cell activation and immune response, brief contacts contribute to the induction of immune-tolerance. Taking advantage of the strong interaction between target cell and activated T-cells, we show the feasibility to identify and isolate tumor-specific cytotoxic T lymphocytes (CTLs) from acute myeloid leukemia (AML) patients. Using this approach, CTLs stably bound through T cell receptor to tumor cells (doublet forming T-cells) can be identified in peripheral blood and bone marrow and subsequently selected and isolated by FACS-based cell sorting. Methods Co-cultures between PBMC from AML patients in complete remission and AML tumor cells (PKH-stained) from the same patient were performed to study the percentage of doublet-forming T cells (CD3+PKH+) (T cell bound to a tumor cell). After 15 hours of co-culture, cells were stained and sorted. Secondary co-cultures with autologous tumor cells (used in primary co-culture) were performed to study the cytotoxic activity and cytokine production of T-cells capable or not to form stable joints with the leukemic cells (doublet population vs non-doublet population). Results Doublet-forming T cells from AML patients were identified in a range of 2% to 6% (mean=3.83%, n=5). Immunophenotyping analysis showed differences between doublet-forming T cells (CD3+PKH+) and those T cells which did not form stable and strong interactions with target cells (CD3+PKH-). Doublet T cells displayed a higher percentage of CD8+ T cells and higher percentage of effector CD4+ and CD8+ T cells compared to non-doublet T cells. Next, we explored, among effector CD4+ and CD8+ cells, those with cytotoxic phenotype. As expected, a high percentage of effector CD8+ doublet T cells showed Granzyme B and perforin expression, thus corresponding with a cytotoxic immune-phenotype (n=3, mean 65.51%). Within effector CD4+ doublet T cells, a mean of 9.053 % showed expression of both Granzyme B and perforin corresponding with CD4+ CTL (n=3). Regarding CD57 and CD16 markers, a mean of 18.62% of effector CD4+ doublet T cells were positive for both markers, compared to 65.84% of effector CD8+ doublet T cells (n=3). Further, we performed secondary co-cultures to analyze the CD69 activation marker after 24h of co-culture. A high percentage of CD69+ cells was observed in co-cultures with doublet-forming T cells against target cells as compared to non-doublet T cells (n=3, p=0.0053). Finally, analysis of supernatants of co-culture of doublet T cells and non-doublet T cells with target cells revealed specific secretion of IFNγ and IL-2 (n=3, p=0.0001; p=0.0005, respectively). The cytolytic activity was evaluated comparing the viability of tumor cells cultured alone or with doublet-forming T cells or non-doublet T cells from the same patient. A significant increase of the specific lysis of AML cells was observed when doublet T cells were co-cultured as compared to non-doublet T cells (p=0.0424, n=5). This encouraged us to examine whether we were able to identify doublet-forming T cells from bone marrow of AML patients at diagnosis. Analyses of bone marrow by flow cytometry reveled a small percentage of CD3+CD34+ population corresponding with bone marrow-doublet-forming T cells (n=3, mean=2.9%). Interestingly, bone marrow-doublet-forming T cells show a higher percentage of CD4+ T cells, whereas bone marrow-non-doublet T cells show a higher percentage of CD8+ T cells. Conclusions Our data demonstrate that when T cells from AML patients are co-cultured with tumor cells, a "doublet T cell" population appears. This population consists of T cells capable to bind tumor cells. These CTLs display higher percentage of effector cells and a marked cytotoxic activity against AML blasts. In conclusion, we have developed a new procedure to identify and select specific cytotoxic T cells in both bone marrow and peripheral blood from patients diagnosed with acute myeloid leukemia. Figure. Figure. Disclosures Sanchez-Abarca: Virgen del Rocio University Hospital: Patents & Royalties. Ramos:Takeda Oncology: Research Funding.

Characterization of Immune Reconstitution Following High Dose Chemotherapy in Acute Myeloid Leukemia.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3888-3888
Author(s):  
Christian F. Meyer ◽  
Christopher Thoburn ◽  
Ferdynand Kos ◽  
Christopher Gocke ◽  
Hyam I. Levitsky ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Peripheral Blood ◽  
Myeloid Leukemia ◽  
Immune Reconstitution ◽  
Consolidation Therapy ◽  
Time Points ◽  
Acute Myeloid

Abstract Recovery of immune function after initial treatment of acute myeloid leukemia (AML) is critical, not only for protection against infections but also for surveillance against recurrent disease. A better understanding of the nature of lymphocyte recovery following induction and consolidation therapy for AML could guide the design of immunotherapy strategies aimed at boosting the anti-leukemia activity of a reconstituted immune system. Prior studies examining thymic T cell production following bone marrow transplantation (BMT) have found varying levels of thymic output post-transplant, as measured by T cell Receptor Excision Circle (TREC) levels in the peripheral blood of adult patients. Of note, relapse of chronic myeloid leukemia (CML) following BMT is correlated with decreased levels of TREC positive T cells. In order to characterize immune reconstitution in AML, we studied 26 patients after induction or consolidation time sequential chemotherapy. Their median age was 52 (range 23–69). Thirteen patients received cytarabine, daunorubicin, and etoposide (AcDVP-16) induction therapy, 3 patients received cytarabine, daunorubicin, and cytarabine (AcDAc) consolidation therapy and 10 patients received flavopiridol, cytarabine, and mitoxantrone (FLAM) either as induction or consolidation therapy. Peripheral blood samples were collected approximately every other day for 3–5 time points after each patient’s white blood cell count exceeded 200 cells/cubic mm on three consecutive days. Among the four patients evaluated to date, flow cytometry results show that a majority of cells seen early in immune reconstitution are CD3+ lymphocytes (range 69–97%). Subset analyses on 3 of these 4 patients have shown CD4:CD8 ratios ranging from 3:1 to 4:1, while the fourth patient exhibited an inverse of this ratio at 1:5. In addition, CD25+FOXP3+ T cells represented a median of 5.1% (range 2.5–12.3%) of the CD3+ T cells. Since T cells represented the abundance of cells in the peripheral blood during early bone marrow recovery, we then assessed whether these cells represented recent thymic emigrants or naïve T cells by examining TRECs using real time PCR (RT-PCR). TRECs were present in 24 of the 26 patients with levels ranging between 100 and 100,000 copies per 100,000 cells. Furthermore, 4 control samples from normal volunteers (ages 37–43) revealed the absence of TREC positive cells. Further analyses of these time points and correlations between TREC levels and clinical responses are ongoing.

Chimeric Antigen Receptor for Specific Targeting of Acute Myeloid Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4225-4225
Author(s):  
Irene Pizzitola ◽  
Fernando Anjos-Afonso ◽  
Kevin Rouault-Pierre ◽  
Francois Lassailly ◽  
Sarah Tettamanti ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Cord Blood ◽  
Myeloid Leukemia ◽  
Genetically Modified ◽  
Target Cells ◽  
Cik Cells ◽  
Acute Myeloid

Abstract Abstract 4225 Despite the progress in the treatment of acute myeloid leukemia (AML) achieved in the last decades, a significant number of patients are still refractory to or relapse after conventional chemotherapy regimens. Therefore it is necessary to develop novel alternative approaches. Immunotherapy with T cells genetically modified to express chimeric antigen receptors (CARs) represent a valid option in this sense. CARs are artificial T-cell receptors constituted by a specific antigen-binding domain, and a signaling region, that, upon antigen recognition, leads to T-cell activation, and lysis of the target cells. AML is a potential optimal target for CAR strategy because of the over-expression of a number of surface antigens like CD33, CD123. Since CD33 is also expressed on normal hematopoietic stem/progenitors cells (HSPCs) resulting in a potential severe impairment of normal myelopoiesis, CD123 has recently emerged as new potential attractive molecules based on its differential expression pattern, being still wildly overexpressed by AML population, and at the same time less expressed on HSPCs. Here we describe the in vivo efficacy and the safety of this approach based on Cytokine-Induced-Killers (CIK) cells genetically modified to express CAR molecules specific for the CD33 or CD123 antigen. Once injected into low-level AML engrafted NSG mice (median of hCD45+CD33+ 0.6% before treatment), genetically modify T cells had a potent antitumor effect. Indeed, the bone marrow of control untreated animals or mice treated with un-manipulated CIK cells, was infiltrated by leukemic cells (86% and 81% leukemic engraftment), while in 7/8 anti-CD33-CD28-OX40-ζ and 8/10 anti-CD123-CD28-OX40-ζ treated mice we couldn't detect any AML cells. Similar results have been obtained when the treatment via T cell injection start when high AML burden has been obtained (median of hCD45+CD33+ 70% before treatment). One week after the last CIK's injection the level of AML engraftment was 96%, 87%, 0.35% and 0.34% for untreated mice, mice treated with un-manipulated CIK cells and with anti-CD33-CD28-OX40-ζ and anti-CD123-CD28-OX40-ζ transduced CIK-cells respectively. We performed secondary transplantation on the residual AML cells present in these animals and mice were treated again with transduced CIK cells. Residual AML cells were still sensitive to CARs approach, leading once again to an almost complete eradication of the disease (median level of hCD45+CD33+ engraftment was 98%, 0.02% and 0.04% respectively for untreated mice, anti-CD33-CD28-OX40-ζ and anti-CD123-CD28-OX40-ζ transduced CIK-cells). Furthermore, a fundamental issue was to determine the safety profile of such approach against normal hematopoietic precursors. In untreated mice injected with primary cord blood derived CD34+ cells the level of engraftment of hCD45 compartment was 42% whilst in mice treated with un-manipulated, anti-CD33-CD28-OX40-ζ or anti-CD123-CD28-OX40-ζ transduced CIK-cells the levels of human compartment was 40%, 11.7% and 26.3% respectively. Moreover when we consider specifically the CD34+CD38- compartment, enriched in HSC, the level of engraftment was 1.92%, 1.02%, 0.55% and 0.83%. Secondary transplantations are now ongoing to give a more complete profile about the remaining HSC repopulating capability after treatment. To more closely mimic a physiological context, similar experiments are ongoing using mice engrafted with normal adult bone marrow instead of umbilical cord blood. These experiments should offer relevant information concerning the efficacy and safety of the proposed strategy particularly in the context of minimal residual disease in high-risk transplanted AML patients. Moreover CAR approach could be potentially used to treat patients resistant to conventional chemotherapeutic approaches or for whom high dose chemotherapy treatment could not be proposed. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Modulating TNFα activity allows transgenic IL15-Expressing CLL-1 CAR T cells to safely eliminate acute myeloid leukemia

2020 ◽  
Vol 8 (2) ◽  
pp. e001229
Author(s):  
Pinar Ataca Atilla ◽  
Mary K McKenna ◽  
Haruko Tashiro ◽  
Madhuwanti Srinivasan ◽  
Feiyan Mo ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Acute Toxicity ◽  
Myeloid Leukemia ◽  
Tnf Alpha ◽  
Car T Cells ◽  
Car T ◽  
Anti Tumor Activity ◽  
Acute Myeloid

BackgroundC-type lectin-like molecule 1 (CLL-1) is highly expressed in acute myeloid leukemia (AML) but is absent in primitive hematopoietic progenitors, making it an attractive target for a chimeric antigen receptor (CAR) T-cell therapy. Here, we optimized our CLL-1 CAR for anti-leukemic activity in mouse xenograft models of aggressive AML.MethodsFirst, we optimized the CLL-1 CAR using different spacer, transmembrane and costimulatory sequences. We used a second retroviral vector to coexpress transgenic IL15. We measured the effects of each construct on T cell phenotype and sequential (recursive) co culture assays with tumor cell targets to determine the durability of the anti tumor activity by flow cytometry. We administered CAR T cells to mice engrafted with patient derived xenografts (PDX) and AML cell line and determined anti tumor activity by bioluminescence imaging and weekly bleeding, measured serum cytokines by multiplex analysis. After euthanasia, we examined formalin-fixed/paraffin embedded sections. Unpaired two-tailed Student’s t-tests were used and values of p<0.05 were considered significant. Survival was calculated using Mantel-Cox log-rank test.ResultsIn vitro, CLL-1 CAR T cells with interleukin-15 (IL15) were less terminally differentiated (p<0.0001) and had superior expansion compared with CD28z-CD8 CAR T cells without IL15 (p<0.001). In both AML PDX and AML cell line animal models, CLL-1 CAR T coexpressing transgenic IL15 initially expanded better than CD28z-CD8 CAR T without IL15 (p<0.0001), but produced severe acute toxicity associated with high level production of human tumor necrosis factor α (TNFα), IL15 and IL2. Histopathology showed marked inflammatory changes with tissue damage in lung and liver. This acute toxicity could be managed by two strategies, individually or in combination. The excessive TNF alpha secretion could be blocked with anti-TNF alpha antibody, while excessive T cell expansion could be arrested by activation of an inducible caspase nine safety switch by administration of dimerizing drug. Both strategies successfully prolonged tumor-free survival.ConclusionCombinatorial treatment with a TNFα blocking antibody and subsequent activation of the caspase-9 control switch increased the expansion, survival and antileukemic potency of CLL-1 CAR T-cells expressing transgenic IL15 while avoiding the toxicities associated with excessive cytokine production and long-term accumulation of activated T-cells.

Emergence of antitumor cytolytic T cells is associated with maintenance of hematologic remission in children with acute myeloid leukemia

Blood ◽  
2006 ◽  
Vol 108 (12) ◽  
pp. 3843-3850 ◽  
Author(s):  
Daniela Montagna ◽  
Rita Maccario ◽  
Franco Locatelli ◽  
Enrica Montini ◽  
Sara Pagani ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Induction Chemotherapy ◽  
Myeloid Leukemia ◽  
Allogeneic Bone Marrow Transplantation ◽  
T Cell Response ◽  
Allogeneic Bone ◽  
Acute Myeloid

AbstractAlthough the graft-versus-leukemia effect of allogeneic bone marrow transplantation (BMT) is of paramount importance in the maintenance of disease remission, the role played by the autologous T-cell response in antitumor immune surveillance is less defined. We evaluated the emergence of antileukemia cytotoxic T-lymphocyte precursors (CTLp's) and the correlation of this phenomenon with maintenance of hematologic remission in 16 children with acute myeloid leukemia (AML), treated with either chemotherapy alone (5 patients) or with autologous BMT (A-BMT, 11 patients). Antileukemia CTLp's were detectable in 8 patients in remission after induction chemotherapy; none of them subsequently had a relapse. Of the 8 patients who did not show detectable CTLp frequency while in remission after induction chemotherapy, 7 subsequently experienced leukemia relapse. In patients undergoing A-BMT, molecular fingerprinting of the TCR-Vβ repertoire, performed on antileukemia lines, demonstrated that selected antileukemia T-cell clonotypes, detectable in bone marrow before transplantation, survived ex vivo pharmacologic purging and were found in the recipient after A-BMT. These data provide evidence for an active role of autologous T cells in the maintenance of hematologic remission and also suggest that quantification of antileukemia CTLp frequency may be a useful tool to identify patients at high risk for relapse, thus potentially benefiting from an allogeneic antitumor effect.

scholarly journals Demethylating therapy increases anti-CD123 CAR T cell cytotoxicity against acute myeloid leukemia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nadia El Khawanky ◽  
Amy Hughes ◽  
Wenbo Yu ◽  
Renier Myburgh ◽  
Tony Matschulla ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Intracellular Signaling ◽  
Myeloid Leukemia ◽  
Epithelial Tissue ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Acute Myeloid

AbstractSuccessful treatment of acute myeloid leukemia (AML) with chimeric antigen receptor (CAR) T cells is hampered by toxicity on normal hematopoietic progenitor cells and low CAR T cell persistence. Here, we develop third-generation anti-CD123 CAR T cells with a humanized CSL362-based ScFv and a CD28-OX40-CD3ζ intracellular signaling domain. This CAR demonstrates anti-AML activity without affecting the healthy hematopoietic system, or causing epithelial tissue damage in a xenograft model. CD123 expression on leukemia cells increases upon 5′-Azacitidine (AZA) treatment. AZA treatment of leukemia-bearing mice causes an increase in CTLA-4negative anti-CD123 CAR T cell numbers following infusion. Functionally, the CTLA-4negative anti-CD123 CAR T cells exhibit superior cytotoxicity against AML cells, accompanied by higher TNFα production and enhanced downstream phosphorylation of key T cell activation molecules. Our findings indicate that AZA increases the immunogenicity of AML cells, enhancing recognition and elimination of malignant cells by highly efficient CTLA-4negative anti-CD123 CAR T cells.

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