Artificial Thymic Organoids Permit Allelic Exclusion and Efficient Generation of Naïve TCR-Engineered T-Cells from Human Hematopoietic Stem Cells In Vitro

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4553-4553
Author(s):  
Christopher S Seet ◽  
Chongbin He ◽  
Michael Bethune ◽  
Suwen Li ◽  
Brent Chick ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Intellectual Property ◽  
Positive Selection ◽  
Allelic Exclusion ◽  
Hematopoietic Stem ◽  
Engineered T Cells ◽  
Selection Of

Abstract Engineered adoptive immunotherapies have shown unprecedented activity in the treatment of cancer and chronic viral infections. Current approaches rely on individualized ex vivo genetic modification of autologous T cells due to the risk of graft-versus-host disease from allogeneic T cells. These processes furthermore require activation and prolonged expansion of T cells, which may reduce in vivo efficacy and persistence. Direct in vitro differentiation of engineered T cells from hematopoietic stem and progenitor cells (HSPCs) may overcome these problems by permitting the suppression of endogenous TCR expression through allelic exclusion, and the de novo generation of naïve antigen-specific T cells. Existing methods of in vitro human T cell differentiation are subject to wide experimental variability and do not adequately support the positive selection of immature T cell precursors to mature T cells, and thus have not been suitable for clinical-scale production of engineered T cells. We report here the preclinical development of an artificial thymic organoid (ATO) system using off-the-shelf, serum-free components and a standardized stromal cell line that supports highly efficient in vitro differentiation and positive selection of native and TCR-engineered human T cells from cord blood (CB), bone marrow, and mobilized peripheral blood CD34+ HSPCs, and purified CD34+CD38- hematopoietic stem cells. ATOs closely recapitulated thymic T cell commitment and differentiation, resulting in greater than 80% CD7+CD5+ T-lineage cells and 50% CD4+CD8+ double positive (DP) T cell precursors by 4 weeks. By 6 weeks, 30-40% of ATO cells were CD3+TCRαβ+ T cells, of which 20-30% were mature CD8 single positive (SP) T cells. CD4SP cells were generated at a lower frequency and later in culture (2-14% of CD3+TCRαβ+ cells). ATO-derived T cells exhibited a naïve CD45RA+CD27+CCR7+CD62L+ phenotype, a diverse, thymic-like TCR repertoire, and robust TCR-dependent cytokine release and proliferation. Transduction of CB CD34+ HSPCs with an HLA-A*02:01-restricted αβ TCR specific for NY-ESO-1 resulted in a markedly increased cell output per ATO (>400-fold, relative to input HSPCs) and enhanced generation of naïve CD3+TCRαβ+CD8αβ+ conventional T cells, the majority of which were antigen-specific by tetramer staining. Positive selection of TCR-engineered naïve T cells could be further enhanced by expression of cognate HLA-A*02:01 in ATO stromal cells. ATO-derived TCR-engineered T cells exhibited a near complete lack of endogenous TCR Vβ expression, consistent with induction of allelic exclusion by the exogenous TCR during T cell development. ATO-derived engineered T cells underwent antigen-specific cytotoxic priming, polyfunctional cytokine release, and proliferation in response to artificial APCs; and exhibited antigen-specific killing of NY-ESO-1+ tumor cells in vitro and in vivo. ATOs thus present a highly efficient off-the-shelf platform for the generation of clinically relevant numbers of naïve and potentially non-alloreactive engineered T cells for adoptive immunotherapy. Clinical translation of the ATO system will be aided by its simplicity, scalability, use of serum-free components, and compatibility with irradiated stromal cells. In addition, genetic manipulation of stem or stromal cell components can be easily incorporated into the system to further enhance downstream T cell engraftment or function. Disclosures Seet: Kite Pharma: Patents & Royalties: Kite Pharma holds an exclusive license to certain intellectual property. Montel-Hagen:Kite Pharma: Patents & Royalties: Kite Pharma holds an exclusive license to certain intellectual property. Crooks:Kite Pharma: Patents & Royalties: Kite Pharma holds an exclusive license to certain intellectual property, Research Funding.

scholarly journals High levels of interleukin 10 production in vivo are associated with tolerance in SCID patients transplanted with HLA mismatched hematopoietic stem cells.

1994 ◽  
Vol 179 (2) ◽  
pp. 493-502 ◽  
Author(s):  
R Bacchetta ◽  
M Bigler ◽  
J L Touraine ◽  
R Parkman ◽  
P A Tovo ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
T Cell ◽  
Mrna Expression ◽  
Fetal Liver ◽  
Hla Antigens ◽  
Interleukin 10 ◽  
Hematopoietic Stem

Transplantation of HLA mismatched hematopoietic stem cells in patients with severe combined immunodeficiency (SCID) can result in a selective engraftment of T cells of donor origin with complete immunologic reconstitution and in vivo tolerance. The latter may occur in the absence of clonal deletion of donor T lymphocytes able to recognize the host HLA antigens. The activity of these host-reactive T cells is suppressed in vivo, since no graft-vs. -host disease is observed in these human chimeras. Here it is shown that the CD4+ host-reactive T cell clones isolated from a SCID patient transplanted with fetal liver stem cells produce unusually high quantities of interleukin 10 (IL-10) and very low amounts of IL-2 after antigen-specific stimulation in vitro. The specific proliferative responses of the host-reactive T cell clones were considerably enhanced in the presence of neutralizing concentrations of an anti-IL-10 monoclonal antibody, suggesting that high levels of endogenous IL-10 suppress the activity of these cells. These in vitro data correlate with observations made in vivo. Semi-quantitative polymerase chain reaction analysis carried out on freshly isolated peripheral blood mononuclear cells (PBMC) of the patient indicated that the levels of IL-10 messenger RNA (mRNA) expression were strongly enhanced, whereas IL-2 mRNA expression was much lower than that in PBMC of healthy donors. In vivo IL-10 mRNA expression was not only high in the T cells, but also in the non-T cell fraction, indicating that host cells also contributed to the high levels of IL-10 in vivo. Patient-derived monocytes were found to be major IL-10 producers. Although no circulating IL-10 could be detected, freshly isolated monocytes of the patient showed a reduced expression of class II HLA antigens. However, their capacity to stimulate T cells of normal donors in primary mixed lymphocyte cultures was within the normal range. Interestingly, similar high in vivo IL-10 mRNA expressions in the T and non-T cell compartment were also observed in three SCID patients transplanted with fetal liver stem cells and in four SCID patients transplanted with T cell-depleted haploidentical bone marrow stem cells. Taken together, these data indicate that high endogenous IL-10 production is a general phenomenon in SCID patients in whom allogenic stem cell transplantation results in immunologic reconstitution and induction of tolerance. Both donor T cells and host accessory cells contribute to these high levels of IL-10, which would suppress the activity of host-reactive T cell in vivo.

scholarly journals A Kinetic Threshold between Negative and Positive Selection Based on the Longevity of the T Cell Receptor–Ligand Complex

1999 ◽  
Vol 189 (10) ◽  
pp. 1531-1544 ◽  
Author(s):  
Calvin B. Williams ◽  
Deborah L. Engle ◽  
Gilbert J. Kersh ◽  
J. Michael White ◽  
Paul M. Allen
Keyword(s):  
T Cells ◽  
T Cell ◽  
Positive Selection ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Ligand Complex ◽  
Altered Peptide Ligands ◽  
Self Peptides ◽  
Selection Of

We have developed a unique in vivo system to determine the relationship between endogenous altered peptide ligands and the development of major histocompatibility complex class II– restricted T cells. Our studies use the 3.L2 T cell receptor (TCR) transgenic mouse, in which T cells are specific for Hb(64–76)/I-Ek and positively selected on I-Ek plus self-peptides. To this endogenous peptide repertoire, we have individually added one of six well-characterized 3.L2 ligands. This transgenic approach expands rather than constrains the repertoire of self-peptides. We find that a broad range of ligands produce negative selection of thymocytes in vivo. When compared with the in vitro TCR–ligand binding kinetics, we find that these negatively selecting ligands all have a half-life of 2 s or greater. Additionally, one of two ligands examined with no detectable binding to the 3.L2 TCR and no activity on mature 3.L2 T cells (Q72) enhances the positive selection of transgenic thymocytes in vivo. Together, these data establish a kinetic threshold between negative and positive selection based on the longevity of TCR–ligand complexes.

scholarly journals Transcription factor Etv6 regulates functional differentiation of cross-presenting classical dendritic cells

2018 ◽  
Vol 215 (9) ◽  
pp. 2265-2278 ◽  
Author(s):  
Colleen M. Lau ◽  
Ioanna Tiniakou ◽  
Oriana A. Perez ◽  
Margaret E. Kirkling ◽  
George S. Yap ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Transcription Factor ◽  
T Cell ◽  
Cd8 T Cells ◽  
Functional Differentiation ◽  
Specific Gene ◽  
Hematopoietic Stem

An IRF8-dependent subset of conventional dendritic cells (cDCs), termed cDC1, effectively cross-primes CD8+ T cells and facilitates tumor-specific T cell responses. Etv6 is an ETS family transcription factor that controls hematopoietic stem and progenitor cell (HSPC) function and thrombopoiesis. We report that like HSPCs, cDCs express Etv6, but not its antagonist, ETS1, whereas interferon-producing plasmacytoid dendritic cells (pDCs) express both factors. Deletion of Etv6 in the bone marrow impaired the generation of cDC1-like cells in vitro and abolished the expression of signature marker CD8α on cDC1 in vivo. Moreover, Etv6-deficient primary cDC1 showed a partial reduction of cDC-specific and cDC1-specific gene expression and chromatin signatures and an aberrant up-regulation of pDC-specific signatures. Accordingly, DC-specific Etv6 deletion impaired CD8+ T cell cross-priming and the generation of tumor antigen–specific CD8+ T cells. Thus, Etv6 optimizes the resolution of cDC1 and pDC expression programs and the functional fitness of cDC1, thereby facilitating T cell cross-priming and tumor-specific responses.

CD3 limits the efficacy of TCR gene therapy in vivo

Blood ◽  
2011 ◽  
Vol 118 (13) ◽  
pp. 3528-3537 ◽  
Author(s):  
Maryam Ahmadi ◽  
Judith W. King ◽  
Shao-An Xue ◽  
Cécile Voisine ◽  
Angelika Holler ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Function ◽  
Cell Receptor ◽  
Surface Expression ◽  
T Cell Function ◽  
Engineered T Cells ◽  
Rate Limiting

Abstract The function of T-cell receptor (TCR) gene modified T cells is dependent on efficient surface expression of the introduced TCR α/β heterodimer. We tested whether endogenous CD3 chains are rate-limiting for TCR expression and antigen-specific T-cell function. We show that co-transfer of CD3 and TCR genes into primary murine T cells enhanced TCR expression and antigen-specific T-cell function in vitro. Peptide titration experiments showed that T cells expressing introduced CD3 and TCR genes recognized lower concentration of antigen than T cells expressing TCR only. In vivo imaging revealed that TCR+CD3 gene modified T cells infiltrated tumors faster and in larger numbers, which resulted in more rapid tumor elimination compared with T cells modified by TCR only. After tumor clearance, TCR+CD3 engineered T cells persisted in larger numbers than TCR-only T cells and mounted a more effective memory response when rechallenged with antigen. The data demonstrate that provision of additional CD3 molecules is an effective strategy to enhance the avidity, anti-tumor activity and functional memory formation of TCR gene modified T cells in vivo.

scholarly journals T Cells Engineered with a Novel Chimeric Receptor Demonstrate Durable In Vivo Efficacy Against Disseminated Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 962-962 ◽  
Author(s):  
Ksenia Bezverbnaya ◽  
Vivian Lau ◽  
Craig Aarts ◽  
Galina Denisova ◽  
Arya Afsahi ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Inhibitory Effect ◽  
In Vivo Efficacy ◽  
Engineered T Cells

Abstract Despite recent therapeutic developments, multiple myeloma remains an incurable plasma cell malignancy. Poor prognosis for myeloma patients relapsing post-transplant calls for the need for novel treatment options. Immunotherapy with engineered T cells has proven highly efficacious against B-cell cancers, and early-phase clinical trials suggest that multiple myeloma is susceptible to this form of therapy. We designed a new chimeric T cell receptor, T cell antigen coupler (TAC), which relies upon activation through endogenous T cell receptor complex, thus allowing engineered T cells to auto-regulate their activity (Helsen et al, Nat. Comm., 2018). Using published single-chain antibody fragments (scFvs) C11D5.3 and J22.9-xi, we generated B cell maturation antigen (BCMA)-specific TAC receptors for targeting multiple myeloma. Primary human T cells were transduced with lentiviral vectors carrying different BCMA TAC constructs and assessed for in vitro functionality via cytokine production, cytotoxicity, and proliferation assays. In vivo efficacy and T cell tracking were performed in an established orthotopic xenograft mouse model based on a BCMA-positive KMS-11 cell line. C11D5.3 and J22.9-xi TAC T cells demonstrated comparable in vitro performance with both types of cultures efficiently killing BCMA-expressing targets, producing IFN-γ, TNF-α, and IL-2 cytokines, and undergoing multiple rounds of proliferation. In vivo, TAC T cells carrying either scFv were capable of curing mice bearing disseminated myeloma; however, the TAC T cells carrying J22.9-xi scFv were more potent on a per-cell basis (Figure 1A, top panel). Mice in remission 3 months post-treatment with a single dose of 106 TAC-positive T cells showed evidence of sustained anti-tumor protection upon rechallenge with a fresh dose of 106 KMS-11 tumor cells (Figure 1B). Mice treated with low-dose J22.9-xi T cells were more resistant to rechallenge than mice treated with a comparable dose of C11D5.3 TAC T cells. Tracking of the TAC T cells in vivo revealed that the J22.9-xi TAC T cells expanded to a much larger extent than the C11D5.3 TAC T cells (Figure 1A, bottom panel), indicating that there were likely more J22.9-xi TAC T cells present at the time of tumor rechallenge. To understand whether biological aspects of BCMA may influence the proliferative response of the TAC T cells, we explored the influence of APRIL, the soluble ligand for BCMA, on TAC T cell proliferation in vitro. Strikingly, despite comparable proliferation of both TAC T cell populations following stimulation with KMS-11 tumor cells in the absence of APRIL in vitro, the presence of APRIL had a strong inhibitory effect on proliferation of C11D5.3 TAC T cells and only a modest inhibitory effect on J22.9-xi TAC T cells. Our preclinical findings support further development of TAC T cells for the treatment of multiple myeloma and underscore the importance of T cell expansion in determining the therapeutic activity of engineered T cells. This work further reveals a novel observation that the natural ligand of BCMA can impair the therapeutic impact of T cells engineered with chimeric receptors directed against BCMA and provide a basis for advancing BCMA-specific TAC T cells into the clinic. Disclosures Denisova: Triumvira Immunologics: Patents & Royalties. Afsahi:Triumvira Immunologics: Patents & Royalties. Helsen:Triumvira Immunologics: Employment, Patents & Royalties. Bramson:Triumvira Immunologics: Employment, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

Hematopoietic Multipotent Progenitor Cells Mobilized by G-CSF Can Inhibit Gvhd

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2969-2969
Author(s):  
Maud D'Aveni ◽  
Julien Rossignol ◽  
Ruddy Montandon ◽  
Marie Bouillie ◽  
Flora Zavala ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Progenitor Cells ◽  
Mechanisms Of Action ◽  
Activated T Cells ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Ifn Γ

Abstract Abstract 2969 Backgound. Acute graft-versus-host-disease (aGVHD) is a frequent life threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT). Despite the infusion of higher doses of T cells with the use of G-CSF-mobilized HSC grafts, the incidence of aGVHD is not increased. The mechanisms by which G-CSF-mobilized HSC can control GVHD are imperfectly elucidated. We previously described the mobilization of murin hematopoïetic progenitor cells (HPCs) by G-CSF and FLT3 ligand capable of inducing tolerance against autoimmune diabetes in the nude mice (Kared, Immunity 2006). We now show that G-CSF can mobilize murin HPCs with immunoregulatory functions in the allogeneic immune response and describe their mechanisms of action. Methods. Mobilization of HPCs is performed by subcutaneous administration of human recombinant G-CSF at 200μg/kg per day, for 4 consecutive days in the C57BL6 (H-2b) mouse. HPCs are collected in the spleen by FACS sorting according to their phenotype: Lin- Sca1high cKithigh FLT3low CD34+ CD106+ CD127−. In vitro, functions and mechanisms of action were analyzed by co-cultures with i) T cells (from C57BL6) activated by anti-CD28 and -CD3 mAbs or activated by BALB/c (H-2d) allogeneic splenic LPS matured dendritic cells, ii) C57BL6 splenic selected CD4+CD25high T regulatory T cells activated by anti-CD28 and -CD3 mAbs iii) activated antitumor specific CD8 T cells (C57BL6 ovalbumin specific TCR transgenic T cells). These different cultures were performed in the presence or absence of inhibitors of selective cytokines or other regulatory molecules. In vivo, we assessed the effect of donor HPCs on GVHD development by injecting C57BL6 derived HPCs (0.5×106/mouse), splenic T cells (1×106/mouse) and T depleted bone marrow cells (5×106/mouse) into lethally irradiated (8 Gy) Balb/c recipients. Results. In vitro, as compared to controls without HPCs, after 3 days of culture, HPCs: 1) promote the proliferation of natural T regs activated by anti-CD3 and anti-CD28 (>80% at 3 days of culture compared to control <50%), 2) inhibit the proliferation of activated T cells (>80% T cells blocked before 4 divisions as compared to control-T cells alone >80% after 4 divisions- p<0, 001) and 3) induce the apoptosis of activated T cells (30% increased, p=0, 01). The proliferation of T regs was cell contact dependant and required the presence of TGF-b. The inhibition of T cell activation required IFN γ produced by activated T-cells and some contact-dependent stimuli. In such pro-inflammatory conditions, HPCs differentiate after 4 days in myeloid derived suppressor cells (MDSC). These cells could then produce NO in response to IFN γ and suppress the proliferation of activated T cell. However, T cell suppression was not dependant on L-arginine depletion. Induction of apoptosis of T cells was Fas/Fas-L dependant. Although in the presence of HPCs the proliferation of CD8+ T TCR transgenic against the dominant ovalbumin epitope SIINFEKL was reduced, the cytotoxic response against the SIINFEKL-pulsed EL4 cell line was enhanced (cytotoxicity >90% with HPCs versus <90% w/o HPCs, p<0, 001). In addition, HPCs express CCR7 and CD62L, which should allow their migration to the sites of allopriming. In vivo, none of the mice that had received allogeneic HSCT with HPCs developed clinical or histological GVHD signs as compared to 50% of the control allografted mice without HPCs. Conclusion. Hematopoietic progenitor cells acquire an immunosuppressive potential after G-CSF mobilization. These cells can be isolated from mobilized peripheral stem cells and suppress GVHD while possibly preserving the GVL effect. Work is underway in humans to identify and amplify this population ex vivo for potential therapeutic application in allogeneic HSCT. Disclosures: No relevant conflicts of interest to declare.

96 Decitabine gene modulation sensitizes human non–small cell lung cancer (NSCLC) to NY-ESO-1 TCR immunotherapy (letetresgene autoleucel; GSK3377794) in vivo

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A107-A107
Author(s):  
Dmitry Pankov ◽  
Ioanna Eleftheriadou ◽  
Anna Domogala ◽  
Sara Brett ◽  
Lea Patasic ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cell ◽  
Human Leukocyte Antigen ◽  
Human Leukocyte ◽  
List Type ◽  
Leukocyte Antigen ◽  
Engineered T Cells

BackgroundNY-ESO-1–specific T cells (letetresgene autoleucel [lete-cel] GSK3377794) are autologous CD4+ and CD8+ T cells transduced to express a high-affinity T-cell receptor (TCR) capable of recognizing NY-ESO-1 and LAGE-1a antigens in complex with human leukocyte antigen (HLA)-A*02. NY-ESO-1 (CTAG1B) and LAGE-1a (CTAG2) are tumor-associated antigens (TAA) that share the SLLMWITQC peptide bound to human leukocyte antigen HLA-A*02 and are expressed in various cancers. Emerging evidence suggests that TCR-engineered T cells targeting NY-ESO-1 hold promise for patients with solid tumors.1 Approximately 75% of synovial sarcomas can over-express NY-ESO-1 vs 12% of NSCLC,2 however, NSCLC expression of NY-ESO-1/LAGE1-a may have therapeutic potential.3 A separate study using engineered T cells targeting NY-ESO-1 has shown a partial response in a patient with advanced lung adenocarcinoma.4 Decitabine (DAC) is a hypomethylating agent and potent inducer of TAA, including NY-ESO-1.5 We have reported in vitro use of DAC to selectively modulate TAA expression in TAA low-expressing tumor cell lines in order to enhance lete-cel therapy.3 The aim of this study was to assess enhancement of combination therapy with lete-cel and DAC in an in vivo NSCLC model.MethodsNOD scid gamma (NSG) mice were injected subcutaneously with the human NSCLC tumor cell line NCI-H1703. Upon engraftment, tumor-bearing mice were treated with a 5-day course of DAC or vehicle control followed by 2 days of rest. Lete-cel was infused on Day 8. RNA was isolated from tumor formalin-fixed paraffin-embedded blocks, and levels of NY-ESO-1 and LAGE-1a transcript were measured by RT-qPCR. Expression pattern of the NY-ESO-1 protein was assessed via immunohistochemistry. Efficacy was defined by changes in tumor volume and systemic IFN-γ secretion.ResultsConsistent with our previous in vitro studies, DAC treatment in vivo resulted in induction of NY-ESO-1 and LAGE-1a in NSCLC tumors. Lete-cel in combination with DAC significantly enhanced antitumor efficacy in vivo compared with lete-cel alone. This was associated with increased interferon-γ secretion. Mice that received DAC treatment only did not show statistically significant tumor reduction compared with untreated mice.Ethics ApprovalAll animal studies were ethically reviewed and carried out in accordance with Animals (Scientific Procedures) Act 1986 and the GSK Policy on the Care, Welfare and Treatment of Animals. Human biological samples were sourced ethically and their research use was in accord with the terms of the informed consents under an Institutional Review Board/Ethics Committee approved protocol.ConclusionsGSK is currently enrolling a Phase Ib/IIa, multi-arm, open-label pilot study (NCT03709706) of lete-cel as a monotherapy or in combination with pembrolizumab in HLA-A*02–positive patients with NSCLC whose tumors express NY-ESO-1/LAGE-1a. This work may support rationale for the use of DAC in combination with lete-cel to improve adoptive T-cell therapy by increasing levels of target antigens and antitumor effect in NSCLC.AcknowledgementsFunding: GSKReferencesD’Angelo SP, Melchiori L, Merchant MS, et al. Cancer Discov 2018;8:944–957.Kerkar SP, Wang Z-F, Lasota J, et al. J Immunother 2016;39:181–187.Eleftheriadou I, Brett S, Domogala A, et al. Ann Oncol 2019:30(Suppl 5):v475–v532.Xia Y, Tian X, Wang J, et al. Oncol Lett 2018;16:6998–7007.Schrump DS, Fischette MR, Nguyen DM, et al. Clin Cancer Res 2006;12:5777–5785.

scholarly journals Cathepsin K maintains the number of lymphocytes in vivo

2020 ◽  
Author(s):  
Renate Hausinger ◽  
Marianne Hackl ◽  
Ana Jardon-Alvarez ◽  
Miriam Kehr ◽  
Sandra Romero Marquez ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cathepsin K ◽  
Hematopoietic Stem ◽  
Cell Numbers ◽  
Cell Compartments ◽  
Lymphocyte Homeostasis

AbstractIn this study, we investigated the influence of the loss of Cathepsin K (Ctsk) gene on the hematopoietic system in vitro and in vivo. We found that cultures with Lineage- SCA1+ KIT+ (LSK) cells on Ctsk deficient stromal cells display reduced colony formation and proliferation, with increased differentiation, giving rise to repopulating cells with reduced ability to repopulate the donor LSK and T cell compartments in the bone marrow. Subsequent in vivo experiments showed impairment of lymphocyte numbers, but, gross effects on early hematopoiesis or myelopoiesis were not found. Most consistently in in vivo experimental settings, we found a significant reduction of (donor) T cell numbers in the bone marrow. Lymphocyte deregulation is also found in transplantation experiments, which revealed that Ctsk is required for optimal regeneration not only of T cells, but also of B cells. Interestingly, cell non-autonomous Ctsk regulates both B- and T cell numbers, but T cell numbers in the bone marrow require an additional autonomous Ctsk-dependent process. Thus, we show that Ctsk is required for the maintenance of hematopoietic stem cells in vitro, but in vivo, Ctsk deficiency most strongly affects lymphocyte homeostasis, particularly of T cells in the bone marrow.

scholarly journals T Cells Engineered with T Cell Antigen Coupler (TAC) Receptors for Haematological Malignancies

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3267-3267
Author(s):  
Christopher Helsen ◽  
Vivian Lau ◽  
Joanne Hammill ◽  
Kenneth Mwawasi ◽  
Danielle Hayes ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cytokine Production ◽  
Haematological Malignancies ◽  
Cell Antigen ◽  
Engineered T Cells ◽  
Post Infusion

Abstract Background: We recently described the T cell antigen coupler (TAC) technology (Helsen et. al. Nature Communications) which is a chimeric receptor that targets antigens in an MHC-independent fashion and activates T cells by co-opting the natural TCR receptor. In vitro and in vivo assessments of TAC T cells in solid tumor models have revealed that TACs mediate biological effects that are distinct from conventional chimeric antigen receptors (CARs) and offer safety advantages, including greater target selectivity and reduced off-target toxicity. Here, we present in vitro and in vivo data showing that TAC-engineered T cells directed against CD19 and BCMA demonstrate robust anti-tumor efficacy in haematological malignancies with no detectable side effects. Materials and Methods: T cells from health donors were engineered with TAC receptors directed against CD19 or BCMA using lentivirus vectors. Flow cytometry was employed to measure surface expression of TAC receptors, cytokine production and proliferation of TAC T cells following stimulation with relevant target cells. Antigen-specific toxicity was measured using a luciferase-based killing assay. Anti-tumor activity was measured against acute lymphoblast leukemia for CD19 and multiple myeloma for BCMA xenografts in immunodeficient NRG mice. Results: Engineering T cells with TAC receptors targeted against either CD19 or BCMA revealed antigen-specific activation of cytokine production, cytotoxic function and proliferation. TAC T cells, but not CAR engineered T cells, show significant selectivity towards the context of antigen presentation. This is reflected by the differential proliferative response to a diverse framework of antigen surface arrangement, potentially indicating that TAC T cells are less susceptible to off target activation and the resulting toxicities. Treatment of established NALM-6 xenografts (acute lymphoblastic leukemia) and KMS-11 xenografts (multiple myeloma) with CD19 TAC T cells and BCMA TAC T cells, respectively, resulted in clearance of tumors within a few weeks of T cell infusion. Mice that cleared tumors following TAC T cell treatment were resistant to subsequent challenge with fresh tumor cells demonstrating persistence of TAC T cells. Treatment with control TAC T cells that carry no binding domain had no impact on tumor growth. Monitoring of TAC T cells post-infusion revealed robust expansion that peaked in the peripheral blood 1-2 weeks post-infusion. A clinical manufacturing protocol has been developed for the CD19 TAC T cells in anticipation of human trials. Conclusion: Our pre-clinical evaluation suggests that TAC therapy has the potential to becoming a safer and more effective alternative to conventional CAR therapy. A first in human Phase I/II trial with CD19 TAC T cells is expected to start in the first half of 2019. Disclosures Helsen: Triumvira Immunologics: Employment, Patents & Royalties. Hammill:Triumvira Immunologics: Other: Holding shares, Patents & Royalties. Mwawasi:Triumvira Immunologics: Other: Holding shares, Patents & Royalties. Hayes:Triumvira Immunologics: Employment. Afsahi:Triumvira Immunologics: Patents & Royalties. Denisova:Triumvira Immunologics: Patents & Royalties. Bramson:Triumvira Immunologics: Employment, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.

Adoptive Transfer of In Vitro Generated T Cell Precursors Enhances Donor T Cell Reconstitution and Graft-Versus-Tumor Activity in Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 63-63 ◽  
Author(s):  
Johannes L. Zakrzewski ◽  
Adam A. Kochman ◽  
Sidney X. Lu ◽  
Theis H. Terwey ◽  
Theo D. Kim ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
Growth Factors ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Hematopoietic Stem ◽  
T Cell Reconstitution

Abstract Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with a varying period of immunoincompetence that particularly affects he T cell lineage resulting in significant morbidity and mortality from opportunistic infections. Recent studies have shown that murine T cells and their precursors can be generated from hematopoietic stem cells (HSC) in vitro using a OP9-DL1 coculture system consisting of OP9 bone marrow stromal cells expressing the Notch 1 ligand Delta-like 1 and growth factors (interleukin 7 and fms-like tyrosine kinase-3 ligand). In this study we determined the effects of adoptively transferred in vitro generated T cell precursors on T cell reconstitution after allogeneic HSCT. We selected HSC (Lin- Sca-1hi c-kithi) from bone marrow (BM) of C57BL/6 mice and cultured these cells on a monolayer of OP9-DL1 cells in the presence of growth factors. These HSC expanded 2,000–5,000-fold within 3–4 weeks and consisted of &gt;95% CD4-CD8-double negative (DN) T cell precursors after 16–28 days of culture. We infused these cells (8x106) with T cell depleted (TCD) BM (5x106) or purified HSC into allogeneic recipients using minor antigen mismatched and MHC class I/II mismatched transplant models. Control mice received TCD BM or purified HSC only. Progeny of OP9-DL1 derived T cell precursors were found in thymus and spleen increasing thymic cellularity and significantly improving thymic and splenic donor T cell chimerism. This effect was even more pronounced when purified HSC instead of whole BM were used as allograft. T cell receptor repertoire and proliferative response to foreign antigen (determined by third party MLR) of in vivo differentiated OP9-DL1 derived mature T cells were intact. Administration of in vitro generated T cell precursors did not induce graft-versus-host disease (GVHD) but mediated significant graft-versus-tumor (GVT) activity (determined by in vivo bioluminescence imaging) resulting in a subsequent significant survival benefit. This advantage was associated with better cytokine responses (IL-2, INF-g, TNF-a) in T cells originating from OP9-DL1 derived T cell precursors compared to BM donor derived T cells. We conclude that the adoptive transfer of OP9-DL1 derived T cell precursors significantly enhances post-transplant T cell reconstitution and GVT activity in the absence GVHD.

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