scholarly journals Increased antitumor efficacy of PD-1-deficient melanoma-specific human lymphocytes

2020 ◽  
Vol 8 (1) ◽  
pp. e000311 ◽  
Author(s):  
Lucine Marotte ◽  
Sylvain Simon ◽  
Virginie Vignard ◽  
Emilie Dupre ◽  
Malika Gantier ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
Adoptive Transfer ◽  
Adoptive Cell Transfer ◽  
Effector Memory ◽  
High Avidity ◽  
Cell Transfer ◽  
T Cell Clones ◽  
Cell Clones

BackgroundGenome editing offers unique perspectives for optimizing the functional properties of T cells for adoptive cell transfer purposes. So far,PDCD1editing has been successfully tested mainly in chimeric antigen receptor T (CAR-T) cells and human primary T cells. Nonetheless, for patients with solid tumors, the adoptive transfer of effector memory T cells specific for tumor antigens remains a relevant option, and the use of high avidity T cells deficient for programmed cell death-1 (PD-1) expression is susceptible to improve the therapeutic benefit of these treatments.MethodsHere we used the transfection of CAS9/sgRNA ribonucleoproteic complexes to editPDCD1gene in human effector memory CD8+T cells specific for the melanoma antigen Melan-A. We cloned edited T cell populations and validatedPDCD1editing through sequencing and cytometry in each T cell clone, together with T-cell receptor (TCR) chain’s sequencing. We also performed whole transcriptomic analyses on wild-type (WT) and edited T cell clones. Finally, we documented in vitro and in vivo through adoptive transfer in NOD scid gamma (NSG) mice, the antitumor properties of WT and PD-1KO T cell clones, expressing the same TCR.ResultsHere we demonstrated the feasibility to editPDCD1gene in human effector memory melanoma-specific T lymphocytes. We showed that PD-1 expression was dramatically reduced or totally absent onPDCD1-edited T cell clones. Extensive characterization of a panel of T cell clones expressing the same TCR and exhibiting similar functional avidity demonstrated superior antitumor reactivity against a PD-L1 expressing melanoma cell line. Transcriptomic analysis revealed a downregulation of genes involved in proliferation and DNA replication in PD-1-deficient T cell clones, whereas genes involved in metabolism and cell signaling were upregulated. Finally, we documented the superior ability of PD-1-deficient T cells to significantly delay the growth of a PD-L1 expressing human melanoma tumor in an NSG mouse model.ConclusionThe use of such lymphocytes for adoptive cell transfer purposes, associated with other approaches modulating the tumor microenvironment, would be a promising alternative to improve immunotherapy efficacy in solid tumors.

Development of a Nonhuman Primate Model for Analysis of the Adoptive Transfer of Antigen-Specific T Cell Clones.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 770-770
Author(s):  
Carolina Berger ◽  
Michael Jensen ◽  
Stanley R. Riddell
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Adoptive Transfer ◽  
Cell Transfer ◽  
Primate Model ◽  
T Cell Clones ◽  
Cell Clones

Abstract In principle, the adoptive transfer of T cell clones specific for antigens expressed by pathogens or malignant cells could be therapeutically effective and allow precise control of the specificity, function, and magnitude of T cell immunity. However, the infusion of large numbers of cultured T cells or T cell clones in clinical trials has frequently failed to eradicate tumors or provide long-term control of infection. This may be due in part to the acquisition of an effector phenotype by the T cells during in vitro culture, which reduces their ability to survive in vivo and establish an immune response of sufficient magnitude for sustained efficacy. Several approaches including the administration of cytokines such as IL15, or lymphodepletion prior to cell transfer might promote the establishment of T cell memory after T cell transfer. To facilitate the rational development of clinical trials of T cell therapy, we have employed a nonhuman primate model of adoptive T cell transfer in which culture conditions and cell doses identical to those in human studies are utilized, and designed strategies to permit rigorous analysis of the persistence, function, phenotype, and migration of transferred cells. CD8+ CTL specific for macaque CMV were detected using an overlapping peptide panel and cytokine flow cytometry, isolated as individual T cell clones by limiting dilution, and propagated to large numbers in vitro. The T cell clones were transduced to express an intracellular truncated CD19 (ΔCD19) surface marker to allow tracking and functional assessment of T cells in vivo, and enriched by immunomagnetic selection to high purity (>98%) prior to transfer. The persistence of transferred ΔCD19+ T cells in the blood and their migration to the bone marrow and lymph nodes was determined by flow cytometry after staining with anti CD19, CD8, and CD3 antibodies. The infusion of ΔCD19+CD8+ CTL (3 x 108/kg) was safe and the cells remained detectable in vivo for >5 months. ΔCD19+CD8+ T cells were easily detected in the blood 1 day after transfer at a level of 2.7% of CD8+ T cells and gradually declined over 56 days to a stable population of 0.15–0.2% of CD8+ T cells. At the time of transfer the ΔCD19+CD8+ T cells had an effector phenotype (CD62L− CD127−), but gradually converted to a CD62L+CD127+ memory phenotype in vivo. The infused T cells were found at high levels in lymph node and bone marrow at day 14 after transfer (1.4% and 2.5%, respectively) and the cells at these sites were predominantly CD62L+. The ΔCD19+CD62L+ T cells lacked direct lytic function and expressed low levels of granzyme B, consistent with memory T cells. Sorting of these cells from post-transfer PBMC showed that in vitro activation restored lytic activity. The transferred ΔCD19+CD62L+ T cells in post-infusion PBMC produced IFNγ and TNFα comparable to endogenous CMV-specific CD8+ CTL. These results demonstrate that a subset (5–10%) of transferred CD8+ CTL clones can persist long-term as functional memory T cells. The macaque CD8+ T cell clones are responsive to IL15 in vitro and a safe regimen for administering IL15 to macaques that boosts endogenous T cells has been identified. Studies are now in progress to determine if IL15 can enhance the efficiency with which effector and memory CD8+ T cell responses can be augmented after adoptive transfer of T cell clones.

Establishing T Cell Memory by Adoptive Transfer of T Cell Clones.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 866-866
Author(s):  
Carolina Berger ◽  
Michael C. Jensen ◽  
Stanley R. Riddell
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Annexin V ◽  
T Cell Memory ◽  
T Cell Clones ◽  
Cell Clones

Abstract Adoptive transfer of T cells has been employed to reconstitute T cell immunity to viruses such as cytomegalovirus (CMV) in immunodeficient allogeneic stem cell transplant (SCT) patients and is being investigated to treat malignancies. In the allogeneic SCT setting, the T cells are derived from the donor and need to be isolated as clones or highly pure populations to avoid graft-versus-host disease. CD8+ T cells can be divided into defined subsets including CD62L− effector memory (TEM) and central memory T cells (TCM) expressing the CD62L lymph node homing molecule. Both TCM and TEM can give rise to cytolytic effector T cells (TE) after antigen stimulation and can be expanded in vitro for immunotherapy. However, the potential of T cells derived from either the TEM or TCM subset to persist in vivo has not been investigated. We used a macaque model to determine whether reconstitution of T cell memory to CMV by adoptive transfer of CD8+ T cell clones depended on their origin from either the CD62L+ TCM or CD62L− TEM subset. T cell clones were retrovirally transduced to express the macaque CD19 or CD20 surface marker to allow tracking of T cells in vivo. Clones derived from both TCM and TEM had similar avidity and proliferative capacity in vitro, and had a TE phenotype (CD62L−CCR7−CD28−CD127−, granzyme B+). TCM and TEM-derived T cell clones were transferred to macaques at doses of 3–6×108/kg and were both detected in the blood one day after transfer at 1.2–2.7% (low dose) to 20–25% (high dose) of CD8+ T cells. However, the frequency of TEM-derived T cells was undetectable after 3–5 days, and the cells were not present in lymph node or bone marrow obtained at day 14. By contrast, TCM-derived clones persisted in peripheral blood, migrated to tissue sites, and were detectable long-term at significant levels. A distinguishing feature of TCM-derived cells was their responsiveness to homeostatic cytokines. Only TCM-derived clones were rescued from apoptotic cell death by low-dose IL15 for >30 days in vitro and this correlated with higher levels of IL15Rα, IL2Rβ, and IL2Rγ, and of Bcl-xL and Bcl-2, which promote cell survival. To determine if the inability of TEM-derived clones to survive in vitro correlated with an increased susceptibility of cell death in vivo, we measured the proportion of infused cells that were positive for propidium iodide (PI) and Annexin V during the short period of in vivo persistence. One day after transfer, 41–45% of TEM-derived T cells were Annexin V+/PI+, analyzed directly in the blood or after 24 hours of culture. By contrast, only a minor fraction of an adoptively transferred TCM-derived T cell clone was Annexin V+/PI+ and the infused cells survived in vivo. A subset of the persisting T cells reacquired TCM marker (CD62L+CCR7+CD127+CD28+) in vivo and regained functional properties of TCM (direct lytic activity; rapid proliferation to antigen). These T cells produced IFN-γ and TNF-α after peptide stimulation, and studies are in progress to assess their in vivo response to antigen by delivery of T cells expressing CMV proteins. Our studies in a large animal model show for the first time that CD8+ TE derived from TCM but not TEM can persist long-term, occupy memory T cell niches, and restore TCM subsets of CMV-specific immunity. Thus, taking advantage of the genetic programming of cells that have become TCM might yield T cells with greater therapeutic activity and could be targeted for human studies of T cell therapy for both viral and malignant disease.

scholarly journals Transition of late-stage effector T cells to CD27+ CD28+ tumor-reactive effector memory T cells in humans after adoptive cell transfer therapy

Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 241-250 ◽  
Author(s):  
Daniel J. Powell ◽  
Mark E. Dudley ◽  
Paul F. Robbins ◽  
Steven A. Rosenberg
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Late Stage ◽  
Adoptive Cell Transfer ◽  
Effector Memory ◽  
Cell Transfer ◽  
Effector Cells

Abstract In humans, the pathways of memory T-cell differentiation remain poorly defined. Recently, adoptive cell transfer (ACT) of tumor-reactive T lymphocytes to metastatic melanoma patients after nonmyeloablative chemotherapy has resulted in persistence of functional, tumor-reactive lymphocytes, regression of disease, and induction of melanocyte-directed autoimmunity in some responding patients. In the current study, longitudinal phenotypic analysis was performed on melanoma antigen-specific CD8+ T cells during their transition from in vitro cultured effector cells to long-term persistent memory cells following ACT to 6 responding patients. Tumor-reactive T cells used for therapy were generally late-stage effector cells with a CD27Lo CD28Lo CD45RA- CD62 ligand- (CD62L-) CC chemokine receptor 7- (CCR7-) interleukin-7 receptor αLo (IL-7RαLo) phenotype. After transfer, rapid up-regulation and continued expression of IL-7Rα in vivo suggested an important role for IL-7R in immediate and long-term T-cell survival. Although the tumor antigen-specific T-cell population contracted between 1 and 4 weeks after transfer, stable numbers of CD27+ CD28+ tumor-reactive T cells were maintained, demonstrating their contribution to the development of long-term, melanoma-reactive memory CD8+ T cells in vivo. At 2 months after transfer, melanoma-reactive T cells persisted at high levels and displayed an effector memory phenotype, including a CD27+ CD28+ CD62L- CCR7- profile, which may explain in part their ability to mediate tumor destruction. (Blood. 2005;105:241-250)

scholarly journals Clonally distinct differentiation trajectories shape CD8+ memory T cell heterogeneity after acute viral infections in humans

2019 ◽  
Author(s):  
Jeff E. Mold ◽  
Laurent Modolo ◽  
Joanna Hård ◽  
Margherita Zamboni ◽  
Anton J.M. Larsson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Yellow Fever ◽  
Cell Response ◽  
Viral Infections ◽  
Yellow Fever Virus ◽  
T Cell Response ◽  
Effector Memory ◽  
T Cell Clones ◽  
Cell Clones

AbstractCD8+ T cells play essential roles in immunity to viral and bacterial infections, and to guard against malignant cells. The CD8+ T cell response to an antigen is composed of many T cell clones with unique T cell receptors, together forming a heterogenous repertoire of phenotypically and functionally distinct effector and memory cells1, 2. How individual T cell clones contribute to this heterogeneity during an immune response is key to understand immunity but remains largely unknown. Here, we longitudinally tracked CD8+ T cell clones expanding in response to yellow fever virus vaccination at the single cell level in humans. We show that only a fraction of the clones detected in the acute response persists as circulating memory T cells, indicative of clonal selection. Clones persisting in the memory phase displayed biased differentiation trajectories along a gradient of stem cell memory (SCM) towards terminally differentiated effector memory (EMRA) fates. Reactivation of single memory CD8+ T cells revealed that they were poised to recapitulate skewed differentiation trajectories in secondary responses, and this was generalizable across individuals for both yellow fever and influenza virus. Together, we show that the sum of distinct clonal differentiation repertoires results in the multifaceted T cell response to acute viral infections in humans.

High Avidity PRAME Specific T Cells Derived From In Vivo HLA Mismatched Transplantation Setting Potentially Useful for Immunotherapeutic Strategies.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4087-4087 ◽  
Author(s):  
Avital L. Amir ◽  
Dirk M. van der Steen ◽  
Renate S. Hagedoorn ◽  
Marieke Griffioen ◽  
J.H. Frederik Falkenburg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Epithelial Cells ◽  
Cell Lines ◽  
High Avidity ◽  
T Cell Clones ◽  
Cell Clones ◽  
T Cell Clone ◽  
Self Antigens

Abstract Abstract 4087 Poster Board III-1022 Adoptive T cell therapy is an attractive strategy to provide cancer patients with antigen specific T cells. For this approach T cells with specificity for non-polymorphic tumor-associated self-antigens that are shared between various tumors are promising candidates. However, the isolation of high avidity T cells specific for nonpolymorphic tumor associated self-antigens is difficult, because of self-tolerance. During thymic selection T cells that exhibit high avidity for self-antigens presented by self-HLA are deleted by positive and negative selection. This explains why most T cells directed against non-polymorphic tumor associated self-antigens characterized to date exhibit low to intermediate avidity. After HLA mismatched stem cell transplantation (SCT) however, T cells educated in the donor have not encountered the allogeneic HLA molecules from the patient during thymic selection. Consequently, these T cells can exhibit high avidity for tumor associated antigens presented by allogeneic patient HLA molecules. In this study we aimed to identify T cells directed against non-polymorphic tumor associated antigens using an in vivo HLA mismatched transplantation setting. Alloreactive T cell clones were isolated and expanded from a patient that experienced graft versus leukemia as well as acute graft versus host disease following HLA-A2 mismatched SCT and donor lymphocyte infusion for the treatment of AML. All isolated T-cell clones were allo-HLA-A2 reactive, and by loading of T2 cells with HPLC fractionations of peptides eluted from HLA-A2 we were able to demonstrate that all alloreactive clones recognized one single fraction, indicative for peptide specific recognition. By two additional peptide HPLC fractionation rounds and mass spectrometry we were able to characterize the peptides of 8 different allo-HLA-A2 reactive T cell clones. One of the T cell clones, was of particular interest since this T cell clone recognized the peptide SLLQHLIGL derived from the preferentially expressed antigen on melanomas (PRAME). Recognition by the clone of HLA-A2 positive COS cells transfected with PRAME, and tetramer staining of the clone, confirmed the specificity against the PRAME derived peptide. Peptide titration demonstrated that the PRAME specific T cell clone exhibited high affinity for the SLL peptide. Since PRAME is overexpressed in a large fraction of tumors, we analyzed whether the PRAME specific clone could recognize HLA-A2 expressing tumor cell lines. The results demonstrated that all 8 tested melanoma cell lines, 2 of 3 RCC cell lines, 1 of 2 mamma carcinoma cell lines and 1 of 2 lung carcinoma cell lines were recognized by the clone. In addition, 5 out of 10 primary acute myeloid leukemia cells, and 2 out of 3 acute lymphoblastic leukemia cell lines were recognized. Since it has been described that also certain normal tissues express low levels of PRAME, the clone was tested against numerous HLA-A2 positive non-malignant cells. No reactivity against fibroblasts, keratinocytes, bronchus epithelial cells, hepatocytes, billiair duct epithelial cells, colon epithelial cells, mesenchymal stem cells, (activated) B-cells, (activated) T cells, monocytes and CD34+ cells was observed. However, the clone demonstrated high reactivity against monocyte derived DC's and a low but significant reactivity against primary tubular epithelial cells. By quantitative PCR we demonstrated that the level of recognition of the different cell types is correlated with the expression levels of PRAME. The results demonstrate that the high avidity PRAME specific T cells clone, derived from an in vivo allo-HLA-A2 immune response, is solely PRAME specific and exerts high reactivity against numerous tumors and limited of target toxicity. Based on these results we conclude that the high affinity TCR from this high avidity PRAME specific T cell may be an effective tool for adoptive T cell therapy using TCR gene modified T cells for the treatment of cancer patients. Disclosures: No relevant conflicts of interest to declare.

High-Affinity CD20-Specific T-Cell Receptors Suitable for Adoptive Immunotherapy in the Treatment of CD20low B-Cell Malignancies

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3837-3837
Author(s):  
Lorenz Jahn ◽  
Pleun Hombrink ◽  
Chopie Hassan ◽  
Michel G.D. Kester ◽  
Renate S. Hagedoorn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
High Avidity ◽  
B Cell Malignancies ◽  
T Cell Clones ◽  
High Affinity ◽  
Cell Clones ◽  
Cd20 Expression ◽  
Self Antigens

Abstract Therapeutic monoclonal antibodies (mAb) such as Rituximab and Ofatumumab have demonstrated the clinical efficacy of targeting the B-cell restricted antigen CD20 for the treatment of B-cell lymphomas and leukemia. Although CD20 is also expressed on healthy B-cell cells which are depleted in the course of therapy, long-term B-cell aplasia is well manageable. However, non-responsive or refractory disease to CD20-targeted mAb treatment has been reported with various mechanisms of resistance: downregulation of CD20 expression, internalization of CD20:mAb complex, inhibition of complement-dependent cytotoxicity and absence of an effector cell repertoire in patients treated with chemotherapy prior to mAb infusion. Therefore, additional therapeutic strategies are required. T-cell receptor (TCR) gene transfer is an attractive strategy to equip T-cells with TCRs of defined antigen-specificity. Due to their high sensitivity for cognate antigen presented in HLA, TCRs can induce T-cell activation even when antigen expression is very low. However, the broad application of TCR-based adoptive immunotherapy directed against self-antigens such as CD20 is hampered by lack of an effective immune response against self-antigens. T-cells carrying high-affinity TCRs reactive to such self-antigens are deleted by negative selection during thymic development to prevent auto-reactivity. An attractive strategy to target self-antigens is to exploiting the immunogenicity of such antigens presented in the context of allogeneic HLA (alloHLA). Here, we used the CD20-derived peptide SLFLGILSV (CD20SLF) binding in HLA-A2 to isolate CD20-reactive T-cells carrying high-affinity TCRs. From peripheral blood mononuclear cells of HLA-A*0201 (HLA-A2)-negative healthy individuals CD8+ T-cells binding to peptide-HLA tetramers composed of CD20SLF bound to HLA-A2 were isolated and clonally expanded. Two high-avidity T-cell clones were identified specific for HLA-A2-bound CD20SLF. CD20-dependent recognition was demonstrated for both clones by transducing the CD20 gene in HLA-A2-positive cell lines which otherwise lack CD20 expression. Both CD20-specific T-cell clones efficiently recognized CD20-expressing HLA-A2-positive primary B-cell malignancies including acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). In addition, the CD20-specific T-cell clones were able to more efficiently recognize ALL cell-lines than CD20-specific mAbs. We demonstrated that on target cells with only very low CD20 surface expression, the CD20-specific T-cell clones could still efficiently recognize endogenously processed CD20-derived peptide in the context of HLA-A2. Furthermore, no recognition of HLA-A2-positive but CD20-negative cell subsets including CD34+hematopoietic progenitor cells, T-cells, immature and mature dendritic cells could be demonstrated. Additionally, recognition of HLA-A2-positive non-hematopoietic cells such as fibroblasts even under simulated inflamed conditions was absent. Transduction of the identified TCRs resulted in efficient expression of the introduced CD20-specific TCRs and conferred CD20-specificity onto recipient cells. In summary, we exploited the immunogenicity of alloHLA to raise high-avidity T-cells against self-antigens such as CD20. The identified CD20-specific T-cell clones efficiently recognized CD20-expressing primary ALL, CLL and MCL. These T-cells clones more efficiently recognized B-cell malignancies than CD20-targeted mAbs while no recognition of CD20-negative hematopoietic and non-hematopoietic cells was observed. Transduction of these CD20-specific TCRs conferred CD20-specificity onto recipient cells. These CD20-specific TCRs can be useful to treat patients with CD20low B-cell malignancies by administering TCR-engineered T cells with potent effector function. Disclosures No relevant conflicts of interest to declare.

scholarly journals 691 Identification of shared tumor epitopes from endogenous retroviruses inducing high avidity cytotoxic T cells for cancer immunotherapy

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A719-A719
Author(s):  
Paola Bonaventura ◽  
Vincent Alcazer ◽  
Virginie Mutez ◽  
Laurie Tonon ◽  
Juliette Martin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Endogenous Retroviruses ◽  
High Avidity ◽  
T Cell Epitopes ◽  
T Cell Clones ◽  
Cell Clones ◽  
Ifn Γ

BackgroundHuman endogenous retroviruses (HERVs) are aberrantly expressed by tumor cells and may represent a source of T cell epitopesMethodsUsing TCGA pancancer RNAseq data (n=8,893 samples), we developed a bioinformatics-based method to select cancer-specific HERVs associated with a cytotoxic T cell response (“cyt-HERVs”) and identify shared T cell epitope candidates. T cells were primed with selected short and long peptide candidates from HLA-A2+ healthy donors. Peptide-specific dextramers were used to sort and expand specific CD8+ T cell clones and determine their TCR sequences and avidity. Cytotoxicity was assessed against HERV-expressing tumor cell lines and patient-derived organoids using Incucyte and Nanolive technologies (Flowchart, figure 1).ResultsIn a pancancer analysis, we identified 57 HML-2/HERV-K HLA-A*0201 epitope candidates from 27 distinct open reading frames. Six shared HLA-A2 strong binders 9-mer peptides, present on multiple HERVs located on different chromosomes, and with translational evidence found in mass spectrometry public datasets, were selected and synthetized. In vitro HLA binding assay confirmed peptide-HLA affinity. Priming assays showed the presence of specific CD8+ T cells leading to polyfunctional IFN-γ+ TNF-α+ T cell responses with upregulation of the degranulation marker CD107A upon co-culture with peptide-pulsed T2 cells. Synthetic long peptides containing the epitopes were used to confirm the correct processing by antigen-presenting cells. The functionality of the sorted T cell clones was confirmed using an Elispot assay (GrzB+ IFN-γ+). Their sequenced TCRs were predicted to stably interact with their respective MHC-peptide complexes in a 3D model. This was confirmed by measurement of the functional avidity, which was in the same order as CMV-specific T cell clones. HERV-specific CD8+ T cells induced specific cell death of HLA-A2+ cancer cell lines, associated with IFN-g production, in a HLA-A2 restricted manner. Finally, pre-existing HERV-specific CD8+ T cells were identified using dextramers among tumor infiltrating lymphocytes (TILs) from cancer patients. HERV-specific T cells co-cultured with patient derived organoids showed signs of activation with lysis of the organoid.ConclusionsOur bioinformatics-based approach allowed us to identify shared HERV-derived CD8+ T cell epitopes specifically expressed by tumor cells and inducing high avidity T cell clones able to kill tumor cells in a class I-restricted manner. The detection of TILs recognizing HERV peptides suggests natural presentation of these epitopes in the tumors. These HERV-derived epitopes may thus represent relevant targets for the development of new cancer vaccines or T cell-based therapies, especially in tumors with low mutational burden.Abstract 691 Figure 1Graphical flowchart of HERV antigen validation. Graphical representation of the flowchart used to identify and validate specific CD8+ T cells for shared tumor epitopes from endogenous retroviruses http://dx.doi.org/10.1136/jitc-2021-SITC2021.691

scholarly journals Development of CAR-T Cell Persistence in Adoptive Immunotherapy of Solid Tumors

2021 ◽  
Vol 10 ◽  
Author(s):  
Jiaqiao Fan ◽  
Jugal Kishore Das ◽  
Xiaofang Xiong ◽  
Hailong Chen ◽  
Jianxun Song
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
Adoptive Cell Transfer ◽  
Great Success ◽  
Cell Transfer ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Chimeric antigen receptor (CAR) T (CAR-T) cell transfer has made great success in hematological malignancies, but only shown a limited effect on solid tumors. One of the major hurdles is the poor persistence of infused cells derived from ex vivo activation/expansion and repeated antigen encounter after re-infusion. Bcl-xL has been demonstrated to play an important role on normal T cell survival and function as well as genetically engineered cells. In the current study, we developed a retroviral CAR construct containing a second-generation carcinoembryonic antigen (CEA)-targeting CAR with the Bcl-xL gene and tested the anti-CEA CAR-T cell immunotherapy for colorectal cancer. In vitro, the anti-CEA CAR-T cells destroyed CEA-expressing tumor cells and sustained survival. In vivo, adoptive cell transfer of anti-CEA CAR-T cells significantly enhanced the ability of the CAR-T cells to accumulate in tumor tissues, suppress tumor growth and increase the overall survival rate of tumor-bearing mice in a murine model of colorectal cancer. These results demonstrate a novel CAR-T platform that has the ability to increase the persistence of CAR-T cells in solid tumors through exogenous expression of persistent genes. The data provide a potentially novel approach to augment CAR-T immunotherapy for solid tumors.

scholarly journals Ex Vivo Monitoring of Antigen-Specific CD4+ T Cells after Recall Immunization with Tetanus Toxoid

2007 ◽  
Vol 14 (9) ◽  
pp. 1108-1116 ◽  
Author(s):  
Catherine Barbey ◽  
Estelle Pradervand ◽  
Nathalie Barbier ◽  
François Spertini
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Tetanus Toxoid ◽  
Ex Vivo ◽  
Interleukin 2 ◽  
Effector Memory ◽  
Specific Response ◽  
T Cell Clones ◽  
Cell Clones

ABSTRACT To monitor antigen-specific CD4+ T cells during a recall immune response to tetanus toxoid (TT), a sequential analysis including ex vivo phenotyping and cytokine flow cytometry, followed by cloning and T-cell-receptor (TCR) spectratyping of cytokine-positive CD4+ T cells, was performed. Grossly, twice as many TT-specific CD4+ T-cell clones, ex vivo derived from the CCR7+/− CD69+ interleukin-2-positive (IL-2+) CD4+ subsets, belonged to the central memory (TCM; CD62L+ CD27+ CCR7+) compared to the effector memory population (TEM; CD62L− CD27− CCR7−). After the boost, a predominant expansion of the TCM population was observed with more limited variations of the TEM population. TCR beta-chain-variable region (BV) spectratyping and sequencing confirmed a large concordance between most frequently expressed BV TCR-CDR3 from ex vivo-sorted CCR7+/− CD69+ IL-2+ CD4+ subsets and BV usage of in vitro-derived TT-specific CD4+ T-cell clones, further demonstrating the highly polyclonal but stable character of the specific recall response to TT. Taken together, ex vivo flow cytometry analysis focused on the CCR7+/− CD69+ IL-2+ CD4+ subsets appears to target the bulk of antigen-specific T cells and to reach an analytical power sufficient to adequately delineate in field trials the profile of the antigen-specific response to vaccine.

Sign in / Sign up

Export Citation Format

Share Document