scholarly journals Precision Engineering of an Anti-HLA-A2 Chimeric Antigen Receptor in Regulatory T Cells for Transplant Immune Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Yannick D. Muller ◽  
Leonardo M. R. Ferreira ◽  
Emilie Ronin ◽  
Patrick Ho ◽  
Vinh Nguyen ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Chimeric Antigen Receptor ◽  
Mononuclear Cells ◽  
Antigen Receptor ◽  
Single Chain ◽  
Transplant Tolerance ◽  
Peripheral Blood Mononuclear

Infusion of regulatory T cells (Tregs) engineered with a chimeric antigen receptor (CAR) targeting donor-derived human leukocyte antigen (HLA) is a promising strategy to promote transplant tolerance. Here, we describe an anti-HLA-A2 CAR (A2-CAR) generated by grafting the complementarity-determining regions (CDRs) of a human monoclonal anti-HLA-A2 antibody into the framework regions of the Herceptin 4D5 single-chain variable fragment and fusing it with a CD28-ζ signaling domain. The CDR-grafted A2-CAR maintained the specificity of the original antibody. We then generated HLA-A2 mono-specific human CAR Tregs either by deleting the endogenous T-cell receptor (TCR) via CRISPR/Cas9 and introducing the A2-CAR using lentiviral transduction or by directly integrating the CAR construct into the TCR alpha constant locus using homology-directed repair. These A2-CAR+TCRdeficient human Tregs maintained both Treg phenotype and function in vitro. Moreover, they selectively accumulated in HLA-A2-expressing islets transplanted from either HLA-A2 transgenic mice or deceased human donors. A2-CAR+TCRdeficient Tregs did not impair the function of these HLA-A2+ islets, whereas similarly engineered A2-CAR+TCRdeficientCD4+ conventional T cells rejected the islets in less than 2 weeks. A2-CAR+TCRdeficient Tregs delayed graft-versus-host disease only in the presence of HLA-A2, expressed either by co-transferred peripheral blood mononuclear cells or by the recipient mice. Altogether, we demonstrate that genome-engineered mono-antigen-specific A2-CAR Tregs localize to HLA-A2-expressing grafts and exhibit antigen-dependent in vivo suppression, independent of TCR expression. These approaches may be applied towards developing precision Treg cell therapies for transplant tolerance.

scholarly journals Precision engineering of an anti-HLA-A2 chimeric antigen receptor in regulatory T cells for transplant immune tolerance

2021 ◽  
Author(s):  
Yannick D. Muller ◽  
Leonardo M.R. Ferreira ◽  
Emilie Ronin ◽  
Patrick Ho ◽  
Vinh Nguyen ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Chimeric Antigen Receptor ◽  
Mononuclear Cells ◽  
Antigen Receptor ◽  
Single Chain ◽  
Transplant Tolerance ◽  
Peripheral Blood Mononuclear

Infusion of regulatory T cells (Tregs) engineered with a chimeric antigen receptor (CAR) targeting donor-derived human leukocyte antigen (HLA) is a promising strategy to promote transplant tolerance. Here, we describe an anti-HLA-A2 CAR (A2-CAR) generated by grafting the complementarity-determining regions (CDRs) of a human monoclonal anti-HLA-A2 antibody into the framework regions of the Herceptin 4D5 single-chain variable fragment and fusing it with a CD28-zeta signaling domain. The CDR-grafted A2-CAR maintained the specificity of the original antibody. We then generated HLA-A2 mono-specific human CAR Tregs either by deleting the endogenous T-cell receptor (TCR) via CRISPR/Cas9 and introducing the A2-CAR using lentiviral transduction or by directly integrating the CAR construct into the TCR alpha constant locus using homology-directed repair. These A2-CAR+TCRdeficient human Tregs maintained both Treg phenotype and function in vitro. Moreover, they selectively accumulated in HLA-A2-expressing islets transplanted from either HLA-A2 transgenic mice or deceased human donors. A2-CAR+TCRdeficient Tregs did not impair the function of these HLA-A2+ islets, whereas similarly engineered A2-CAR+TCRdeficientCD4+ conventional T cells rejected the islets in less than 2 weeks. A2-CAR+TCRdeficient Tregs delayed graft-versus-host disease only in the presence of HLA-A2, expressed either by co-transferred peripheral blood mononuclear cells or by the recipient mice. Altogether, we demonstrate that genome-engineered mono-antigen-specific A2-CAR Tregs localize to HLA-A2-expressing grafts and exhibit antigen-dependent in vivo suppression, independent of TCR expression. These approaches may be applied towards developing precision Treg cell therapies for transplant tolerance.

High levels of thyroid hormone impair regulatory T cells function via reduced PD-1 expression

2021 ◽  
Author(s):  
Yi Zhong ◽  
Ting-Ting Lu ◽  
Xiao-Mei Liu ◽  
Bing-Li Liu ◽  
Yun Hu ◽  
...  
Keyword(s):  
T Cells ◽  
Thyroid Hormone ◽  
Regulatory T Cells ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Dependent Manner ◽  
Peripheral Blood Mononuclear

Abstract Context Regulatory T cells (Tregs) dysfunction plays an important role in the development and progression of Graves’ disease (GD). Programmed cell death 1 (PD-1) prompts FoxP3 in Tregs expression and enhances the suppressive activity of Tregs. Whether abnormal expression of PD-1 contributes to the breakdown of Tregs and the role of thyroid hormone in the PD-1 expression of Tregs in GD remain substantially undefined. Objective To evaluate the role of PD-1 in Tregs function and triiodothyronine (T3) in PD-1 expression in patients with GD and mice treated with T3. Methods We recruited 30 patients with GD and 30 healthy donors. PD-1 expression in Tregs and Tregs function were determined. To evaluate the effects of thyroid hormone on PD-1 expression in Tregs, we used T3 for the treatment of human peripheral blood mononuclear cells (PBMCs). We then treated mice with T3 to confirm the effect of thyroid hormone on PD-1 expression in Tregs and Tregs function in vivo. Results PD-1 expression in Tregs and the suppressive function of Tregs significantly decreased in patients with GD. T3 reduced PD-1 expression in human Tregs in a concentration- and time-dependent manner in vitro. High levels of circulating T3 reduced PD-1 expression in Tregs, impaired Tregs function, and disrupted T-helper cell (Th1 and Th2) balance in mice treated with T3. Conclusions Tregs dysfunction in GD patients might be due to down-regulation of PD-1 expression in Tregs induced by high levels of serum T3.

112 Rational design of chimeric antigen receptor T cells against glypican 3 decouples toxicity from therapeutic efficacy

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A124-A124
Author(s):  
Letizia Giardino ◽  
Ryan Gilbreth ◽  
Cui Chen ◽  
Erin Sult ◽  
Noel Monks ◽  
...  
Keyword(s):  
T Cells ◽  
Chimeric Antigen Receptor ◽  
Antigen Receptor ◽  
Single Chain ◽  
High Affinity ◽  
Car T Cells ◽  
Car T ◽  
Animal Care ◽  
Cytotoxic Function

BackgroundChimeric antigen receptor (CAR)-T therapy has yielded impressive clinical results in hematological malignancies and it is a promising approach for solid tumor treatment. However, toxicity, including on-target off-tumor antigen binding, is a concern hampering its broader use.MethodsIn selecting a lead CAR-T candidate against the oncofetal antigen glypican 3 (GPC3), we compared CAR bearing a low and high affinity single-chain variable fragment (scFv,) binding to the same epitope and cross-reactive with murine GPC3. We characterized low and high affinity CAR-T cells immunophenotype and effector function in vitro, followed by in vivo efficacy and safety studies in hepatocellular carcinoma (HCC) xenograft models.ResultsCompared to the high-affinity construct, the low-affinity CAR maintained cytotoxic function but did not show in vivo toxicity. High-affinity CAR-induced toxicity was caused by on-target off-tumor binding, based on the evidence that high-affinity but not low-affinity CAR, were toxic in non-tumor bearing mice and accumulated in organs with low expression of GPC3. To add another layer of safety, we developed a mean to target and eliminate CAR-T cells using anti-TNFα antibody therapy post-CAR-T infusion. This antibody functioned by eliminating early antigen-activated CAR-T cells, but not all CAR-T cells, allowing a margin where the toxic response could be effectively decoupled from anti-tumor efficacy.ConclusionsSelecting a domain with higher off-rate improved the quality of the CAR-T cells by maintaining cytotoxic function while reducing cytokine production and activation upon antigen engagement. By exploring additional traits of the CAR-T cells post-activation, we further identified a mechanism whereby we could use approved therapeutics and apply them as an exogenous kill switch that would eliminate early activated CAR-T following antigen engagement in vivo. By combining the reduced affinity CAR with this exogenous control mechanism, we provide evidence that we can modulate and control CAR-mediated toxicity.Ethics ApprovalAll animal experiments were conducted in a facility accredited by the Association for Assessment of Laboratory Animal Care (AALAC) under Institutional Animal Care and Use Committee (IACUC) guidelines and appropriate animal research approval.

scholarly journals CD137 Co-Stimulation Improves The Antitumor Effect Of LMP1-Specific Chimeric Antigen Receptor T Cells In Vitro And In Vivo

2019 ◽  
Vol Volume 12 ◽  
pp. 9341-9350 ◽  
Author(s):  
Xiaojun Tang ◽  
Qi Tang ◽  
Yuan Mao ◽  
Xiaochen Huang ◽  
Lizhou Jia ◽  
...  
Keyword(s):  
T Cells ◽  
Chimeric Antigen Receptor ◽  
Antitumor Effect ◽  
Antigen Receptor

scholarly journals Induction of CD4+CD25+ Regulatory T Cells from In Vitro Grown Human Mononuclear Cells by Sparteine Sulfate and Harpagoside

Biology ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 211 ◽  
Author(s):  
Nour Z. Atwany ◽  
Seyedeh-Khadijeh Hashemi ◽  
Manju Nidagodu Jayakumar ◽  
Mitzi Nagarkatti ◽  
Prakash Nagarkatti ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Mononuclear Cells ◽  
Cultured Cells ◽  
Inflammatory Responses ◽  
Human Peripheral Blood ◽  
Stimulation Index ◽  
Tgf Beta ◽  
Peripheral Blood Mononuclear

Regulatory T cells (Tregs) are key players in the regulation of inflammatory responses. In this study, two natural molecules, namely, sparteine sulfate (SS) and harpagoside (Harp), were investigated for their ability to induce Tregs in human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from healthy volunteers and grown in the presence or absence of ConA, with TGF-beta, SS or Harp. Expression of the mRNA of FoxP3, TGF-beta, IL-10 and GAPDH was assessed via q-PCR. The expression of Treg markers including CD4, CD25, CD127 and FoxP3 was measured via flow cytometry. The secretion of IL-10 and TGF-beta by cultured cells was assessed by ELISA. Furthermore, the suppressive role of SS and Harp on PBMCs in vitro was tested via allogeneic mixed lymphocyte reaction (MLR). Data obtained show that both compounds increased the expression of FoxP3, TGF-beta and IL-10 mRNA in resting PBMCs but to a lesser extent in activated cells. Moreover, they significantly increased the percent of CD4+CD25+FoxP3+CD127− Tregs in activated and naïve PBMCs. Functionally, both compounds caused a significant reduction in the stimulation index in allogeneic MLR. Together, our data demonstrate for the first time that SS and Harp can induce human Tregs in vitro and therefore have great potential as anti-inflammatory agents.

scholarly journals Simian Immunodeficiency Virus SIVagm Efficiently Utilizes Non-CCR5 Entry Pathways in African Green Monkey Lymphocytes: Potential Role for GPR15 and CXCR6 as Viral Coreceptors

2015 ◽  
Vol 90 (5) ◽  
pp. 2316-2331 ◽  
Author(s):  
Nadeene E. Riddick ◽  
Fan Wu ◽  
Kenta Matsuda ◽  
Sonya Whitted ◽  
Ilnour Ourmanov ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Rhesus Macaques ◽  
Target Cells ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Sooty Mangabeys ◽  
Natural Hosts

ABSTRACTAfrican green monkeys (AGM) are natural hosts of simian immunodeficiency virus (SIV), and infection in these animals is generally nonpathogenic, whereas infection of nonnatural hosts, such as rhesus macaques (RM), is commonly pathogenic. CCR5 has been described as the primary entry coreceptor for SIVin vivo, while human-derived CXCR6 and GPR15 also appear to be usedin vitro. However, sooty mangabeys that are genetically deficient in CCR5 due to an out-of-frame deletion are infectible with SIVsmm, indicating that SIVsmm can use alternative coreceptorsin vivo. In this study, we examined the CCR5 dependence of SIV strains derived from vervet AGM (SIVagmVer) and the ability of AGM-derived GPR15 and CXCR6 to serve as potential entry coreceptors. We found that SIVagmVer replicated efficiently in AGM and RM peripheral blood mononuclear cells (PBMC) in the presence of the CCR5 antagonist maraviroc, despite the fact that maraviroc was capable of blocking the CCR5-tropic strains SIVmac239, SIVsmE543-3, and simian-human immunodeficiency virus SHIV-AD8 in RM PBMC. We also found that AGM CXCR6 and AGM GPR15, to a lesser extent, supported entry of pseudotype viruses bearing SIVagm envelopes, including SIVagm transmitted/founder envelopes. Lastly, we found that CCR5, GPR15, and CXCR6 mRNAs were detected in AGM and RM memory CD4+T cells. These results suggest that GPR15 and CXCR6 are expressed on AGM CD4+T cells and are potential alternative coreceptors for SIVagm usein vivo. These data suggest that the use of non-CCR5 entry pathways may be a common feature of SIV replication in natural host species, with the potential to contribute to nonpathogenicity in these animals.IMPORTANCEAfrican green monkeys (AGM) are natural hosts of SIV, and infection in these animals generally does not cause AIDS, whereas SIV-infected rhesus macaques (RM) typically develop AIDS. Although it has been reported that SIV generally uses CD4 and CCR5 to enter target cellsin vivo, other molecules, such as GPR15 and CXCR6, also function as SIV coreceptorsin vitro. In this study, we investigated whether SIV from vervet AGM can use non-CCR5 entry pathways, as has been observed in sooty mangabeys. We found that SIVagmVer efficiently replicated in AGM and RM peripheral blood mononuclear cells in the presence of the CCR5 antagonist maraviroc, suggesting that non-CCR5 entry pathways can support SIVagm entry. We found that AGM-derived GPR15 and CXCR6 support SIVagmVer entryin vitroand may serve as entry coreceptors for SIVagmin vivo, since their mRNAs were detected in AGM memory CD4+T cells, the preferred target cells of SIV.

scholarly journals CRISPR-mediated insertion of a chimeric antigen receptor produces nonviral T cell products capable of inducing solid tumor regression

2021 ◽  
Author(s):  
Katherine Mueller ◽  
Nicole Piscopo ◽  
Matthew Forsberg ◽  
Louise Saraspe ◽  
Amritava Das ◽  
...  
Keyword(s):  
T Cells ◽  
Chimeric Antigen Receptor ◽  
Viral Vectors ◽  
Viral Vector ◽  
Tumor Regression ◽  
Antigen Receptor ◽  
Car T Cells ◽  
Car T

Chimeric antigen receptor (CAR) T cells traditionally harbor viral vectors that encode the CAR transgene in the genome. However, viral vector manufacturing typically is resource intensive, suffers from batch-to-batch variability, and includes several animal components, adding regulatory and supply chain pressures. Here, CAR T cells were generated within nine days using recombinant SpCas9 protein and nucleic acids, without any viral vectors or animal components. In comparison to traditional retroviral CAR T cells, nonviral CRISPR CAR T cells exhibit TRAC-targeted genomic integration of the CAR transgene, higher frequency of gene expression signatures associated with a memory phenotype, low receptor signaling prior to infusion, and potent cytotoxicity against GD2+ neuroblastoma in vitro and in vivo. This proof-of-principle study eliminating viral vectors and animal components during CAR gene transfer could enable more flexible and scalable manufacturing of clinically-relevant, high-quality CAR T cells to treat cancers, including solid tumors.

Development of human NKG2D-CD3ε chimeric antigen receptor (CAR) for T-cell-mediated cancer immunotherapy.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 150-150
Author(s):  
Sergei Kusmartsev ◽  
Johaness Vieweg ◽  
Victor Prima
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Chimeric Antigen Receptor ◽  
Antigen Receptor ◽  
Adaptor Protein ◽  
T Cell Subsets ◽  
Human T Cells

150 Background: NKG2D is a lectin-like type 2 transmembrane receptor that expressed by natural killer cells and some T cell subsets. Stimulation of NKG2D receptor with specific agonistic ligands produces activating signals through signaling adaptor protein DAP10 leading to the enhanced cytokine production, proliferation, and cytotoxicity against tumor cells. There is strong evidence that NKG2D ligands are expressed in many human tumors, including melanoma, leukemia, myeloma, glioma, and carcinomas of the prostate, breast, lung, and colon. Recent studies also demonstrated that T cells bearing chimeric antigen receptor (CAR) NKG2D linked to CD3ζ (zeta) chain produce marked in vitro and in vivo anti-tumor effects. The aim of current study was to determine whether human T cells bearing chimeric antigen receptor (CAR) NKGD2 linked to CD3ε (epsilon) chain could be activated by the NKG2D-specific stimulation and able to kill human cancer cells. Given the important role of CD3ε in activation and survival of T cells, we hypothesized that NKG2D-CDε-bearing T cells could exert strong in vitro and in vivo anti-tumor effects. Methods: NKG2D CAR was produced by linking human NKG2D to DAP10 and the cytoplasmic portion of the CD3ε chain. Original full-length human cDNA clones were obtained from NIH Mammalian Gene Collection (MGC). Functional domain analysis and oligonucleotide design in the in-Fusion system of DNA cloning (Clontech) was used to generate the retroviral expression constructs. Results: Human PBMC-derived T cells were retrovirally transduced with newly generated NKG2D-CD3ε CAR DNA construct. These NKG2D CAR-expressing human T cells responded to NKG2D-specific activation by producing IFN-γ and exhibited significant cellular cytotoxicity against human tumor cells in vitro. In vivo studies demonstrated that NKG2D-CD3ε-bearing cells are capable of inhibiting growth of DU-145 human prostate cancer in the immunodeficient mice. Conclusions: Collectively, our data indicate the feasibility of developing chimeric antigen receptor NKG2D-CD3ε for T cells and suggest that adoptive transfer of T cells bearing NKG2D-CD3ε CAR could be potentially effective for immunotherapy of cancer patients.

Potential TH9402-Based ECP Treatment for cGvHD Patients.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 5119-5119
Author(s):  
Annie Levesque ◽  
Ann-Louise Savard ◽  
Denis-Claude Roy ◽  
Francine Foss ◽  
Christian Scotto
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Chronic Phase ◽  
Dose Effect ◽  
Peripheral Blood Mononuclear ◽  
Hematopoietic Stem

Abstract Although the risk of graft versus host disease (GvHD) can be reduced by improved donor-recipient matching and by the depletion of T cells before transplantation, GvHD still develops in 30–70% of allogeneic hematopoietic stem cell transplantation (HSCT) patients. The chronic phase of the disease (cGvHD), for which the pathogenesis is similar to autoimmune diseases, involves profound immune dysregulation leading to both immunodeficiency and autoimmunity. Standard therapies for cGvHD such as corticosteroids and immunosuppressants are associated with high toxicity and have demonstrated limited efficacy in patients with extensive disease. Extracorporeal photopheresis (ECP) has been shown by others in the clinic as a non-aggressive and beneficial alternative treatment for cGvHD, inducing Th1/Th2 immunomodulation that restores immunological tolerance. Celmed has developed an alternative approach to eliminate immunoreactive T cells using the Theralux™ photodynamic cell therapy (PDT) system based on the use of the rhodamine-123 derivative TH9402 illuminated ex vivo with a visible light source (λ =514nm). It has been suggested that the apoptotic cells, when returned to the patient, may be able to modulate the immune system as seen with other ECP methods. We aimed to evaluate in vivo and in vitro the possibility of also using the Theralux™ system in the ECP setting. A preliminary mouse model suggested that splenic T cells pre-treated with the Theralux™ system were able to induce an improvement of overall survival (p<0.05) in mice with acute GvHD. Additionally, we developed a simplified PDT process and conducted a series of experiments with peripheral blood mononuclear cells (PBMCs) isolated from healthy volunteers. These studies have shown that the intra- and inter-donor variability in TH9402 incorporation are very low (~5% and 10%, respectively). A dose-effect study has shown a relationship of the PDT conditions with the levels of cell death, allowing significant control of the level of apoptosis induced. Phenotypic analyses have shown that this process results in an increase of AnnexinV positive cells as well as a decrease in the absolute number of CD3+ cells, CD19+/CD20+ cells and CD14+ cells and an increase in CD11c+ cells. This would suggest that apoptosis could be induced in both autoreactive T and B cells which could potentially stimulate an immune response against them. Moreover, the increase in CD11c+ cells combined with the decrease in CD14+ cells could reflect the maturation of macrophages into dendritic cells that are very potent antigen presenting cells. The mechanism by which these specific PDT conditions induce cell death is still under investigation but preliminary studies have shown that the cell death in unselected resting PBMCs may be caspase-independent. Finally, the evaluation of the effect of PDT on samples from cGvHD patients also demonstrated the capacity of this treatment strategy to induce apoptosis in these cells. Based on these data, we intend to begin a pilot clinical study evaluating two controlled PDT conditions inducing different levels of apoptosis in order to assess the safety and biological effect of the Theralux™ ECP system to treat patients with cGvHD.

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