Off-the-Shelf Partial HLA Matching SARS-CoV-2 Antigen Specific T Cell Therapy: A New Possibility for COVID-19 Treatment

BackgroundImmunological characteristics of COVID-19 show pathological hyperinflammation associated with lymphopenia and dysfunctional T cell responses. These features provide a rationale for restoring functional T cell immunity in COVID-19 patients by adoptive transfer of SARS-CoV-2 specific T cells.MethodsTo generate SARS-CoV-2 specific T cells, we isolated peripheral blood mononuclear cells from 7 COVID-19 recovered and 13 unexposed donors. Consequently, we stimulated cells with SARS-CoV-2 peptide mixtures covering spike, membrane and nucleocapsid proteins. Then, we culture expanded cells with IL-2 for 21 days. We assessed immunophenotypes, cytokine profiles, antigen specificity of the final cell products.ResultsOur results show that SARS-CoV-2 specific T cells could be expanded in both COVID-19 recovered and unexposed groups. Immunophenotypes were similar in both groups showing CD4+ T cell dominance, but CD8+ and CD3+CD56+ T cells were also present. Antigen specificity was determined by ELISPOT, intracellular cytokine assay, and cytotoxicity assays. One out of 14 individuals who were previously unexposed to SARS-CoV-2 failed to show antigen specificity. Moreover, ex-vivo expanded SARS-CoV-2 specific T cells mainly consisted of central and effector memory subsets with reduced alloreactivity against HLA-unmatched cells suggesting the possibility for the development of third-party partial HLA-matching products.DiscussionIn conclusion, our findings show that SARS-CoV-2 specific T cell can be readily expanded from both COVID-19 and unexposed individuals and can therefore be manufactured as a biopharmaceutical product to treat severe COVID-19 patients.One Sentence SummaryEx-vivo expanded SARS-CoV-2 antigen specific T cells developed as third-party partial HLA-matching products may be a promising approach for treating severe COVID-19 patients that do not respond to previous treatment options.

Download Full-text

Virus Induced Lymphocytes (VIL) as a novel viral antigen-specific T cell therapy for COVID-19 and potential future pandemics

Scientific Reports ◽

10.1038/s41598-021-94654-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Rohan Sivapalan ◽

Jinyan Liu ◽

Krishnendu Chakraborty ◽

Elisa Arthofer ◽

Modassir Choudhry ◽

...

Keyword(s):

Immune Response ◽

T Cell ◽

Cell Therapy ◽

Time Course ◽

Mononuclear Cells ◽

Adoptive Cell Therapy ◽

Rapid Expansion ◽

Effector Memory ◽

Antigen Specificity ◽

T Cell Therapy

AbstractThe a priori T cell repertoire and immune response against SARS-CoV-2 viral antigens may explain the varying clinical course and prognosis of patients having a mild COVID-19 infection as opposed to those developing more fulminant multisystem organ failure and associated mortality. Using a novel SARS-Cov-2-specific artificial antigen presenting cell (aAPC), coupled with a rapid expansion protocol (REP) as practiced in tumor infiltrating lymphocytes (TIL) therapy, we generate an immune catalytic quantity of Virus Induced Lymphocytes (VIL). Using T cell receptor (TCR)-specific aAPCs carrying co-stimulatory molecules and major histocompatibility complex (MHC) class-I immunodominant SARS-CoV-2 peptide-pentamer complexes, we expand virus-specific VIL derived from peripheral blood mononuclear cells (PBMC) of convalescent COVID-19 patients up to 1000-fold. This is achieved in a clinically relevant 7-day vein-to-vein time-course as a potential adoptive cell therapy (ACT) for COVID-19. We also evaluate this approach for other viral pathogens using Cytomegalovirus (CMV)-specific VIL from donors as a control. Rapidly expanded VIL are enriched in virus antigen-specificity and show an activated, polyfunctional cytokine profile and T effector memory phenotype which may contribute to a robust immune response. Virus-specific T cells can also be delivered allogeneically via MHC-typing and patient human leukocyte antigen (HLA)-matching to provide pragmatic treatment in a large-scale therapeutic setting. These data suggest that VIL may represent a novel therapeutic option that warrants further clinical investigation in the armamentarium against COVID-19 and other possible future pandemics.

Download Full-text

A Randomized Phase II Study of Xcellerated T Cells™ with or without Prior Fludarabine Therapy in Patients with Relapsed or Refractory Multiple Myeloma.

Blood ◽

10.1182/blood.v104.11.2410.2410 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2410-2410

Author(s):

James R. Berenson ◽

Ivan M. Borrello ◽

Ravi Vij ◽

Asad Bashey ◽

Thomas Martin ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Nk Cells ◽

Magnetic Beads ◽

Mononuclear Cells ◽

Ex Vivo ◽

New Drugs ◽

M Protein ◽

High Dose ◽

T Cell Therapy

Abstract Background: T cells from myeloma subjects can be activated and expanded ex vivo using the Xcellerate™ Process, in which peripheral blood mononuclear cells are incubated with anti-CD3 and anti-CD28 antibody-coated magnetic beads (Xcyte™-Dynabeads®). In a previous study (Borrello et al., ASCO 2004), Xcellerated T Cells administered to myeloma subjects following high dose chemotherapy and autologous stem cell transplantation led to accelerated lymphocyte recovery and restoration of the T cell receptor repertoire. In the current study, subjects with relapsed or refractory myeloma were randomized to Xcellerated T Cells with or without one cycle of fludarabine prior to Xcellerated T Cells. Fludarabine is being used to assess the influence of lymphoablation on the anti-tumor and immune reconstitution effects of T cell therapy; it has previously been reported to have no significant activty in myeloma (Kraut et al., Invest. New Drugs, 1990). Methods: Approximately 30 subjects are planned to receive treatment. Each receives a single dose of 60–100 x 109 Xcellerated T Cells. Subjects on the fludarabine arm receive a single cycle (5 days at 25 mg/m2), completed 4 days prior to the Xcellerated T Cell infusion. Results: 17 subjects have been enrolled and 13 treated to date, with median last f/u visit of 28 days (range 0–140). Xcellerated T Cells were successfully manufactured in all subjects, with T cell expansion 136 ± 61 fold (mean ± SD), with 79.2 ± 13.8 x 109 cells infused, and final product 98.0 ± 2.0% T cells (n=13). There have been no reported serious adverse events related to Xcellerated T Cells. In the fludarabine arm, lymphocytes decreased from 1,228 ± 290/mm3 (mean ± SEM) to 402 ± 164 following fludarabine, and then increased to 1,772 ± 278 on Day 14 following T cell infusion (n=7). In the non-fludarabine arm, lymphocyte counts increased from 1,186 ± 252 to 3,204 ± 545 on Day 14 (n=4). Lymphocytes were comprised of both CD4+ and CD8+ T cells. Increases were observed in NK cells from 77 ± 26 to 121 ± 25, monocytes from 166 ± 44 to 220 ± 30 and platelets from 218 ± 16 to 235 ± 24 by Day 14 (n=11). In the non-fludarabine arm, neutrophils increased from 3.6 ± 0.9 to 4.8 ± 0.6 on Day 1. On the fludarabine arm, 3 of 6 subjects developed Grade 4 neutropenia and one developed Grade 3 thrombocytopenia. Seven subjects were evaluable for serum M-protein measurements to Day 28. One of three fludarabine treated subjects had an M-protein decrease of 38%. Conclusions: Xcellerated T Cells were well-tolerated and led to increased lymphocytes, including T cells and NK cells. Increases in other hematologic parameters, including neutrophils and platelets were also observed. In this patient population, fludarabine is lymphoablative and also can cause neutropenia and thrombocytopenia. The fludarabine schedule has been decreased from 5 to 3 days. A decrease in M-protein has been observed in one of three fludarabine-treated subjects; data on additional subjects will be presented.

Download Full-text

Vaccinated C57BL/6 Mice Develop Protective and Memory T Cell Responses to Coccidioides posadasii Infection in the Absence of Interleukin-10

Infection and Immunity ◽

10.1128/iai.01148-13 ◽

2013 ◽

Vol 82 (2) ◽

pp. 903-913 ◽

Cited By ~ 14

Author(s):

Chiung-Yu Hung ◽

Natalia Castro-Lopez ◽

Garry T. Cole

Keyword(s):

T Cells ◽

T Cell ◽

Ex Vivo ◽

Interleukin 10 ◽

Effector Memory ◽

Wild Type ◽

Coccidioides Posadasii ◽

Content Type ◽

Cell Immunity ◽

Ifn Γ

ABSTRACTHigh concentrations of lung tissue-associated interleukin-10 (IL-10), an anti-inflammatory and immunosuppressive cytokine, correlate with susceptibility of mice toCoccidioidesspp. infection. In this study, we found that macrophages, dendritic cells, neutrophils, and both CD8+and CD4+T cells recruited toCoccidioides posadasii-infected lungs of nonvaccinated and vaccinated mice contributed to the production of IL-10. The major IL-10-producing leukocytes were CD8+T cells, neutrophils, and macrophages in lungs of nonvaccinated mice, while both Foxp3+and Foxp3−subsets of IL-10+CD4+T cells were significantly elevated in vaccinated mice. Profiles of the recruited leukocytes in lungs revealed that only CD4+T cells were significantly increased inIL-10−/−knockout mice compared to their wild-type counterparts. Furthermore,ex vivorecall assays showed that CD4+T cells isolated from vaccinatedIL-10−/−mice compared to vaccinated wild-type mice produced significantly higher amounts of IL-2, gamma interferon (IFN-γ), IL-4, IL-6, and IL-17A in the presence of a coccidioidal antigen, indicating that IL-10 suppresses Th1, Th2, and Th17 immunity toCoccidioidesinfection. Analysis of absolute numbers of CD44+CD62L−CD4+T effector memory T cells (TEM) and IFN-γ- and IL-17A-producing CD4+T cells in the lungs ofCoccidioides-infected mice correlated with better fungal clearance in nonvaccinatedIL-10−/−mice than in nonvaccinated wild-type mice. Our results suggest that IL-10 suppresses CD4+T-cell immunity in nonvaccinated mice duringCoccidioidesinfection but does not impede the development of a memory response nor exacerbate immunopathology of vaccinated mice over at least a 4-month period after the last immunization.

Download Full-text

Safety and exceptional immunogenicity of novel 5T4 viral vectored vaccination regimes in early stage prostate cancer: a phase I clinical trial

10.1101/2020.03.05.20031500 ◽

2020 ◽

Cited By ~ 1

Author(s):

Federica Cappuccini ◽

Richard Bryant ◽

Emily Pollock ◽

Lucy Carter ◽

Clare Verrill ◽

...

Keyword(s):

Prostate Cancer ◽

T Cells ◽

T Cell ◽

Mononuclear Cells ◽

Ex Vivo ◽

Early Stage ◽

Specific Antigen ◽

T Cell Responses ◽

Cell Responses ◽

Cell Immunity

AbstractProstate cancer (PCa) has been under investigation as a target for antigen-specific immunotherapies in metastatic disease settings for a decade. However, neither of the two clinically most developed prostate cancer vaccines, Sipuleucel-T and ProstVac, induce strong T cell immunity. In this first-in-man study, VANCE, we evaluated a novel vaccination platform based on two replication-deficient viruses, chimpanzee adenovirus (ChAd) and MVA (Modified Vaccinia Ankara), targeting the oncofetal self-antigen 5T4 in early stage PCa. Forty patients, either newly diagnosed with early stage prostate cancer and scheduled for radical prostatectomy or patients with stable disease on an active surveillance protocol, were recruited to the study to assess the vaccine safety and T cell immunogenicity. Secondary and exploratory endpoints included immune infiltration into the prostate, prostate specific antigen (PSA) change and assessment of phenotype and functionality of antigen-specific T cells. The vaccine had an excellent safety profile. Vaccination-induced 5T4-specific T cell responses were measured in blood by ex vivo IFN-γ ELISpot and were detected in the majority of patients with a mean level in responders of 198 spot-forming cells (SFC) per million peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis demonstrated the presence of both CD8+ and CD4+ polyfunctional 5T4-specific T cells in the circulation. 5T4-reactive tumour infiltrating lymphocytes (TILs) were isolated from post-treatment prostate tissue. Some of the patients had a transient PSA rise 2-8 weeks following vaccination, possibly indicating an inflammatory response in the target organ. The potent T cell responses elicited support the evaluation of these vectored vaccine in efficacy trials.

Download Full-text

Most Closely HLA-Matched Third Party Allogeneic CMV Specific T-Cells Generated Using the Cytokine Capture System for the Treatment of CMV Infections after Allogeneic Stem Cell Transplantation

Blood ◽

10.1182/blood.v128.22.4547.4547 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4547-4547

Author(s):

Betul Oran ◽

Muharrem Muftuoglu ◽

Indreshpal Kaur ◽

Li Li ◽

Eric Yvon ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mononuclear Cells ◽

Ex Vivo ◽

Third Party ◽

Systemic Steroid ◽

Cmv Infection ◽

Simple Method ◽

Ifn Gamma ◽

Specific Ctls

Abstract Adoptive immunotherapy with ex vivo expanded virus-specific T-cell lines from transplant donors has emerged as a potentially curative approach for the treatment of drug-refractory viral infections complicating allogeneic hematopoietic cell transplants (HSCT). In these studies, viral-specific T cells are generated in compliance with current good manufacturing practice (cGMP) following repeated rounds of antigen-driven stimulation over a number of weeks. Such protocols are logistically and technically demanding, requiring access to specialized GMP units and are difficult to apply in urgent clinical settings. The cytokine-capture (gamma-catch) procedure is a fast and simple method that takes <30 hours to isolate polyclonal IFN-gamma-secreting CD8+ and CD4+ viral-specific T cells and can be performed outside a dedicated GMP facility. The cells are directly transfused to the patient without the requirement for ex vivo expansion. The use of allogeneic third party T-cell donors offers the option of selecting donors with high viral-specific T cell precursor frequencies and may serve as an alternative for patients receiving an allogeneic cord blood transplant or a transplant from a virus-seronegative donor. Here, we report the interim results of a Phase 2 study in 11 patients with persistent CMV infection after HSCT, despite optimum anti-viral therapy for at least 14 days. We established a bank of cryopreserved peripheral blood mononuclear cells (PBMCs) from 36 healthy donors. Eligible patients were treated with small numbers of CMV-specific T cells selected by cytokine capture from the most closely HLA-matched third party donor. Manufacture of third party derived CMV specific CTLs was performed at the MDACC Core Facility. Cryopreserved PBMCs were thawed, washed and diluted at 1 × 109 cells in 100 mL MACS GMP TexMACS Reagent (Miltenyi Biotec) for approximately 16 hours at 37°C. The product was stimulated with MACS® GMP Peptivator® HCMV pp65 for approximately 4 hours at 37°C, CO2. Enrichment of cytokine-secreting cells was performed using the cytokine secretion system and the CliniMACS device for immunomagnetic separation. CMV-specific T cells were transfused directly after isolation without any further in vitro expansion. To date, 11 HSCT recipients have received CMV-specific T-cells generated by gamma-catch. Of 11 patients, 2 had failed to respond to foscarnet, 12 to ganciclovir and 8 to both agents. One patient who had a complete response (CR) to his first CMV-specific T-cell infusion received a second infusion 166 days after the first dose for the treatment of CMV retinitis. The median number of infused CD3+IFN-gamma+ T-cells was 2598/kg (range, 61/kg-12717/kg). There were no immediate infusion-related adverse events. CMV-specific CTLs controlled infection in 9 of 11 evaluable infusions; 6 CR and 3 partial response (PR). The overall response and CR rates at 4 weeks were 77% (95%CI; 51%, 95%) and 54.5% (95%CI; 25.4%, 78.6%). Interestingly, the success of adoptive T-cell transfer was not related to the dose of infused T-cells. The median ratio of CD8+ IFN-gamma+ to CD4+ IFN-gamma+ T-cells was 2.7 (range, 0.17-13.4). Among 6 CR patients, 4 had a second episode of CMV infection at a median of 71 days (range, 61-355 days) after the first CTL infusion. Following infusion, there was expansion of both CD8+ and/or CD4+ CMV-specific T-cells, which persisted for a minimum of 1 month following infusion. Recurrence of CMV PCR after CTL infusion was associated with loss of CMV CTL response. Despite the use of third-party donors with HLA disparity, only one patient developed de novo graft versus host disease (GVHD) of the gastrointestinal tract (grade 1) 3 months after CTL infusion. Three patients with a history of acute GVHD prior to CTL infusion had flares 5-6 months after CTL infusions and responded to systemic steroid use. In summary, these interim results demonstrate the safety, feasibility and efficacy of immunotherapy with the most closely HLA-matched CMV specific CTLs generated by cytokine capture for the treatment of drug resistant CMV infection after HSCT patients. The clinical trial continues to enroll and an updated report of the study will be presented at the meeting. Disclosures Ciurea: Spectrum Pharmaceuticals: Other: Advisory Board; Cyto-Sen Therapeutics: Equity Ownership.

Download Full-text

Targeting CD38 is lethal to Breg-like chronic lymphocytic leukemia cells and Tregs, but restores CD8+ T-cell responses

Blood Advances ◽

10.1182/bloodadvances.2019001091 ◽

2020 ◽

Vol 4 (10) ◽

pp. 2143-2157 ◽

Cited By ~ 1

Author(s):

Alak Manna ◽

Timothy Kellett ◽

Sonikpreet Aulakh ◽

Laura J. Lewis-Tuffin ◽

Navnita Dutta ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Chronic Lymphocytic Leukemia ◽

Cd8 T Cells ◽

Mononuclear Cells ◽

Transforming Growth Factor ◽

Ex Vivo ◽

Xenograft Model ◽

Lymphocytic Leukemia ◽

Dependent Manner

Abstract Patients with chronic lymphocytic leukemia (CLL) are characterized by monoclonal expansion of CD5+CD23+CD27+CD19+κ/λ+ B lymphocytes and are clinically noted to have profound immune suppression. In these patients, it has been recently shown that a subset of B cells possesses regulatory functions and secretes high levels of interleukin 10 (IL-10). Our investigation identified that CLL cells with a CD19+CD24+CD38hi immunophenotype (B regulatory cell [Breg]–like CLL cells) produce high amounts of IL-10 and transforming growth factor β (TGF-β) and are capable of transforming naive T helper cells into CD4+CD25+FoxP3+ T regulatory cells (Tregs) in an IL-10/TGF-β-dependent manner. A strong correlation between the percentage of CD38+ CLL cells and Tregs was observed. CD38hi Tregs comprised more than 50% of Tregs in peripheral blood mononuclear cells (PBMCs) in patients with CLL. Anti-CD38 targeting agents resulted in lethality of both Breg-like CLL and Treg cells via apoptosis. Ex vivo, use of anti-CD38 monoclonal antibody (mAb) therapy was associated with a reduction in IL-10 and CLL patient-derived Tregs, but an increase in interferon-γ and proliferation of cytotoxic CD8+ T cells with an activated phenotype, which showed an improved ability to lyse patient-autologous CLL cells. Finally, effects of anti-CD38 mAb therapy were validated in a CLL–patient-derived xenograft model in vivo, which showed decreased percentage of Bregs, Tregs, and PD1+CD38hiCD8+ T cells, but increased Th17 and CD8+ T cells (vs vehicle). Altogether, our results demonstrate that targeting CD38 in CLL can modulate the tumor microenvironment; skewing T-cell populations from an immunosuppressive to immune-reactive milieu, thus promoting immune reconstitution for enhanced anti-CLL response.

Download Full-text

IMMU-31. QUANTITATIVE EVALUATION OF ROUTES OF ADMINISTRATION OF IMMUNOTHERAPEUTIC T CELLS TO ORTHOTOPIC GLIOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.461 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii111-ii111

Author(s):

Lan Hoang-Minh ◽

Angelie Rivera-Rodriguez ◽

Fernanda Pohl-Guimarães ◽

Seth Currlin ◽

Christina Von Roemeling ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Growth ◽

Ex Vivo ◽

Adoptive T Cell Therapy ◽

Whole Body ◽

T Cell Therapy ◽

Clinical Responses

Abstract SIGNIFICANCE Adoptive T cell therapy (ACT) has emerged as the most effective treatment against advanced malignant melanoma, eliciting remarkable objective clinical responses in up to 75% of patients with refractory metastatic disease, including within the central nervous system. Immunologic surrogate endpoints correlating with treatment outcome have been identified in these patients, with clinical responses being dependent on the migration of transferred T cells to sites of tumor growth. OBJECTIVE We investigated the biodistribution of intravenously or intraventricularly administered T cells in a murine model of glioblastoma at whole body, organ, and cellular levels. METHODS gp100-specific T cells were isolated from the spleens of pmel DsRed transgenic C57BL/6 mice and injected intravenously or intraventricularly, after in vitro expansion and activation, in murine KR158B-Luc-gp100 glioma-bearing mice. To determine transferred T cell spatial distribution, the brain, lymph nodes, heart, lungs, spleen, liver, and kidneys of mice were processed for 3D imaging using light-sheet and multiphoton imaging. ACT T cell quantification in various organs was performed ex vivo using flow cytometry, 2D optical imaging (IVIS), and magnetic particle imaging (MPI) after ferucarbotran nanoparticle transfection of T cells. T cell biodistribution was also assessed in vivo using MPI. RESULTS Following T cell intravenous injection, the spleen, liver, and lungs accounted for more than 90% of transferred T cells; the proportion of DsRed T cells in the brains was found to be very low, hovering below 1%. In contrast, most ACT T cells persisted in the tumor-bearing brains following intraventricular injections. ACT T cells mostly concentrated at the periphery of tumor masses and in proximity to blood vessels. CONCLUSIONS The success of ACT immunotherapy for brain tumors requires optimization of delivery route, dosing regimen, and enhancement of tumor-specific lymphocyte trafficking and effector functions to achieve maximal penetration and persistence at sites of invasive tumor growth.

Download Full-text

Functionally specialized human CD4+ T-cell subsets express physicochemically distinct TCRs

eLife ◽

10.7554/elife.57063 ◽

2020 ◽

Vol 9 ◽

Author(s):

Sofya A Kasatskaya ◽

Kristin Ladell ◽

Evgeniy S Egorov ◽

Kelly L Miners ◽

Alexey N Davydov ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Receptors ◽

Adaptive Immune System ◽

T Cell Subsets ◽

Effector Memory ◽

Intrinsic Properties ◽

Antigen Specificity ◽

Adaptive Immune ◽

Transition Pathways

The organizational integrity of the adaptive immune system is determined by functionally discrete subsets of CD4+ T cells, but it has remained unclear to what extent lineage choice is influenced by clonotypically expressed T-cell receptors (TCRs). To address this issue, we used a high-throughput approach to profile the αβ TCR repertoires of human naive and effector/memory CD4+ T-cell subsets, irrespective of antigen specificity. Highly conserved physicochemical and recombinatorial features were encoded on a subset-specific basis in the effector/memory compartment. Clonal tracking further identified forbidden and permitted transition pathways, mapping effector/memory subsets related by interconversion or ontogeny. Public sequences were largely confined to particular effector/memory subsets, including regulatory T cells (Tregs), which also displayed hardwired repertoire features in the naive compartment. Accordingly, these cumulative repertoire portraits establish a link between clonotype fate decisions in the complex world of CD4+ T cells and the intrinsic properties of somatically rearranged TCRs.

Download Full-text

T Cell Immunity Toward Viral- and Tumor-Antigens Is Preserved in MDS Patients

Blood ◽

10.1182/blood-2019-126792 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4225-4225

Author(s):

Hussein Hamad ◽

Wingchi K Leung ◽

Spyridoula Vasileiou ◽

Shivani Mukhi ◽

Quillan Huang ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Healthy Donor ◽

Tumor Antigens ◽

Ex Vivo ◽

Advisory Committees ◽

Cell Immunity ◽

Healthy Donors ◽

T Cell Lines

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders characterized by bone marrow failure and a propensity to progress to acute myeloid leukemia (AML). A core component of the underlying pathogenesis in MDS is deregulation of inflammatory cytokines, such as tumor growth factor-β (TGFβ), which impact the function of immune cells and hence their capacity to mount anti-infective or anti-tumor responses. However, little is known about antigen-specific T cell function in patients with MDS. We hypothesized that virus-specific T cell (VST) function might be preserved in patients with MDS, and that the functional capacity of T cells reactive against tumor-associated antigens aberrantly overexpressed by clonal MDS cells such as Cyclin A1 (CCNA1) and Proteinase (PR3) might also be preserved and exploited for immunotherapeutic purposes. Following informed consent, we collected peripheral blood samples from 10 patients (pts) with MDS and 17 healthy donors. Most pts (9 out of 10) were transfusion dependent and 3 subsequently underwent an allogeneic HSCT. Table 1 summarizes the other clinical characteristics, karyotypic and mutational profile at the time of blood collection. Compared with T cells isolated from healthy donors, MDS patient-derived T cells had a similar CD4 to CD8 ratio (1.5-2.5:1 for healthy donors and 3:1 for MDS pts), but displayed a more exhausted profile at baseline (CD3+TIM3+: 1% in healthy donors and 5% in MDS pts) and produced higher levels of inflammatory cytokines [IFNγ (18±3pg/ml vs 36±16pg/ml, healthy donor vs MDS; p=0.12), and IL-8 (56±32 vs 704±446 pg/ml, p=0.01)]. Next, to assess the capacity of MDS pts to mount ex vivo functional virus-directed responses, we stimulated patient-derived PBMCs (n=5) with overlapping peptide libraries (pepmixes) spanning immunogenic AdV, CMV, EBV, BK and HHV-6 antigens. Similar to healthy donor-derived T cell lines (n=5, 3 specific for 4 viruses and 2 for 5 viruses), all 5 MDS patient-derived lines demonstrated specificity for one or more of the target viruses (1 for 5 viruses, 1 for 4, 2 for 3 and 1 for 1 virus) as observed by IFNγ ELISpot assay with comparable magnitude (range Adv: 43-730 vs 384-941 in healthy donors, CMV: 0-1599 vs 0-3002, EBV: 0-1486 vs 0-541, BK: 0-839 vs 38-275 and HHV6: 0-794 vs 5-407 SFU/2x105 cells, respectively). We next examined the feasibility of expanding autologous MDS-antigen directed T cell products (n=10) to determine whether an adoptive immunotherapeutic approach might be applicable for MDS treatment. Thus, we exposed patient-derived PBMCs to autologous dendritic cells (DC) loaded with pepmixes spanning 6 MDS-associated antigens (CCNA1, survivin, WT1, PRAME, PR3 and NYESO1). After 3 rounds of stimulation, the products obtained were predominantly CD3+ T cells (mean 88±1.3%) that were polyclonal (CD4: 46±5% and CD8: 41±4%) containing predominantly memory T cells (TEM: 36±6% TCM: 37±5% and Tnaïve =13±3%). Six lines (60%) showed specific recognition to at least one of the target antigens: 4 lines specific for PRAME, 1 for CCNA1, 1 for WT1 and 1 for NYESO1 (range 0-40, 0-184, 0-1386 and 0-179 SFU/2x105 cells, respectively by IFNγ ELIspot). T cell lines were capable of specifically secreting multiple effector cytokines in response to targets (TNFα: 12% and IFNγ: 16% in response to PRAME in a representative patient-derived T cell line). Furthermore, this line was capable of killing PRAME+ targets in a 4hr 51Cr release assay [60% specific lysis, E:T 20:1]. In conclusion, functional virus-directed T cell immunity in patients with MDS is preserved, potentially explaining the lower rates of viral reactivation seen in these patients compared with other infections. Moreover, T cells specific for MDS-expressed tumor antigens can also be successfully expanded ex vivo from patients. Taken together this raises the possibility of applying an adoptive immunotherapeutic approach for the treatment of MDS. Disclosures Ramos: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tessa Therapeutics: Research Funding. Leen:Allovir: Consultancy, Other: Cofounder, Ownership Interest; Marker Therapeutics: Consultancy, Other: Cofounder, Ownership Interest.

Download Full-text

708 Novel ways to exploit IL-21 to augment adoptive T cell transfer therapy against tumors

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.708 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A737-A737

Author(s):

Anna Cole ◽

Guillermo Rangel RIvera ◽

Aubrey Smith ◽

Megan Wyatt ◽

Brandon Ware ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Immune Cells ◽

Striking Difference ◽

T Cell Therapy ◽

Cell Immunity ◽

Emory University

BackgroundIL-21 enhances the anti-tumor capacity of adoptively transferred CD8+ T cells, while IL-2 and IL-15 impair T cell immunity by driving their expansion to a more differentiated status. Yet, these cytokines can act on many different immune cells. Given the potency of IL-21, we tested if this cytokine directly augments T cells or rather if it enhances other immune cells in the culture that indirectly improves T cell therapy.MethodsTo test this question, splenocytes from pmel-1 transgenic mice were used, as all CD8+ T cells express a transgenic TCR specific for tumor-antigen gp10025–33 overexpressed on melanoma. We then peptide activated naïve CD8+ T cells enriched or not from the spleen of pmel-1 mice and expanded them in the presence of IL-21 or IL-2 (10 ng/mL) for four days. Expanded pmel-1 from these various cultures were then restimulated with irradiated splenocytes pulsed with gp10025–33 and grown an additional seven days with IL-2 (10 ng/mL), irrespective of their initial cytokine condition. The in vitro memory phenotype, exhaustion profile, and cytokine secretion of these cultures were then assayed. Furthermore, mice bearing B16KVP melanoma tumors were infused with pmel-1 T cells expanded via these various approaches and compared for their relative capacity to engraft, persist, and regress tumor in vivo.ResultsInterestingly, we discovered that IL-21-treated T cells generated from bulk splenocytes are phenotypically and functionally distinct from IL-21-treated isolated T cells. Upon restimulation, IL-21-treated T cells from bulk splenocytes exhibited an exhausted phenotype that was like anergic IL-2-treated T cells. Moreover, few cells expressed CD62L but expressed heightened markers of suppression, including TIM3, PD-1, and EOMES. Moreover, they produced more effector molecules, including granzyme B and IFN-gamma. In vivo IL-21-treated T cells expanded from bulk splenocytes engrafted and persisted poorly, in turn mediating suboptimal regression of melanoma. Conversely, IL-21 dramatically bolstered the engraftment and antitumor activity of T cells only if they were first isolated from the spleen prior to their expansion and infusion into the animal.ConclusionsCollectively, our data shows that IL-21 may improve ACT therapy best when used directly on antitumor CD8+ T cells. Further studies will illuminate the mechanism behind this striking difference and determine whether other cell subsets reactive to IL-21 cause T cell dysfunction and/or reduced bioavailability. These findings are important for defining the best culture conditions in which to use IL-21 for ACT.AcknowledgementsWe would like to acknowledge Emory University, The Winship Cancer Institute, and the Pediatrics/Winship Flow Cytometry Core.Ethics ApprovalAll animal procedures were approved by the Institutional Animal Care and Use Committee of Emory University, protocol number 201900225.

Download Full-text