Wilms´Tumor 1 Protein Is Highly Expressed on Malignant Plasma Cells and Provides a Novel Target for Immunotherapeutic Approaches

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 98-98 ◽  
Author(s):  
Guenther Koehne ◽  
Satyajit Kosuri ◽  
Ekaterina Doubrovina ◽  
Tao Dao ◽  
Andrew Scott ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Therapeutic Potential ◽  
Wilms Tumor ◽  
Human Igg1 ◽  
Wilms Tumor 1

Abstract Introduction: The Wilms' tumor 1 (WT1) protein is a tumor associated antigen that is potentially targetable by immunotherapeutic approaches. We have demonstrated the overexpression of WT1 in myeloma cells by IHC and in HLA-A*0201+ pts by staining with a high-affinity fully human IgG1 mAb (ESK1) specific to the RMFPNAPYL/HLA-A*0201 complex on malignant plasma cells. We report initial results from pts with plasma cell leukemia (PCL) or relapsed/refractory multiple myeloma (rMM) who have been treated with CD34-selected allo transplants followed by the administration of donor-derived WT1-specific T-cell infusions to induce an immunotherapeutic effect. Methods: In situ expression of WT1 was assessed by IHC analyses using a sequential double staining technique of MoAbs specific for CD138 and WT1.For staining with the RMFPNAPYL/HLA-A*0201 complex, BM samples were blocked with human FcR Blocking Reagent and then directly stained with MoAbs specific for CD38, CD56, CD45 and ESK1 or its isotype control human IgG1 and were analyzed by flow cytometry. WT1-specific T cells were generated from the original stem cell donors by sensitization of CD3+ enriched T-cell fractions with autologous APCs loaded with the pool of overlapping pentadecapeptides of WT1 (Invitrogen, Boston, MA). Cells were propagated in vitro with weekly restimulation and supplementation with IL-2 beginning at day 10-16. After 35-49 days, T-cells were harvested, counted and tested for antigen specific cytotoxicity, HLA-restriction, lack of alloreactivity and sterility. Pts received CD34-selected PBSC allografts after myeloablative cytoreduction with busulfan, melphalan and fludarabine. Pts were treated with 3 infusions of donor-derived WT1-specific T-cell infusions (5x10e6 cells/kg) starting 6 weeks post allo HSCT and at 4 weekly thereafter. Results: Marrow from all pts with immunohistochemical documented plasma cell involvement stained positive for WT1 IHC while WT1 staining remained negative in pts in CR. Only pts expressing HLA-A*0201 that stained positively for WT1 by IHC also demonstrated expression of WT1 by the RMFPNAPYL/HLA-A*0201 complex, whereas pts lacking HLA-A*0201 but with active disease stained positive for WT1 IHC but not ESK1 staining. Of 7 pts, 3 PCL and 4 rMM, treated with WT1-specific T cells, 4 pts had persistent disease post CD34-selected allotransplant. Of these 4 pts 2 pts developed a striking rise of WT1-specific T-cell frequencies and developed a complete remission post WT1 CTL infusions lasting for >2years. Conclusion: WT1 is overexpressed on malignant plasma cells and serves as a target for potential immunotherapeutic approaches in pts with multiple myeloma. Pts with persistent PCL following CD34-selected allografts treated with adoptive transfer of donor-derived WT1-specific cytotoxic T cells can achieve long lasting remission underscoring the therapeutic potential of T-cells specific for immunogenic WT1 peptides expressed on malignant plasma cells. Disclosures O'Reilly: Atara Biotherapeutics: Research Funding.

scholarly journals REGN5458, a Bispecific BCMAxCD3 T Cell Engaging Antibody, Demonstrates Robust In Vitro and In Vivo Anti-Tumor Efficacy in Multiple Myeloma Models, Comparable to That of BCMA CAR T Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1944-1944 ◽  
Author(s):  
David J Dilillo ◽  
Kara Olson ◽  
Katja Mohrs ◽  
T. Craig Meagher ◽  
Kevin Bray ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Plasma Cells ◽  
Myeloma Cell ◽  
Car T Cells ◽  
Nsg Mice ◽  
Car T

Abstract Improving therapies for multiple myeloma (MM) remains a high medical need because of the significant morbidity and mortality of the disease. Targeted immunotherapies represent a promising opportunity to fill this clinical need. B cell maturation antigen (BCMA) is an attractive cell-surface target for MM due to its consistent expression on MM patient malignant plasma cells and expression limited in normal tissue primarily to plasma cells. Redirection of a patient's T cells to recognize tumors by CD3-binding bispecific molecules or through the generation of chimeric antigen receptor (CAR) T cells, has shown preliminary evidence of clinical activity. Bispecific antibodies concurrently engage a tumor antigen on cancer cells and the CD3 signaling machinery on T cells, bringing the tumor cell and T cell into proximity and facilitating T cell activation and tumor cell killing. By contrast, CAR T cell therapy involves re-infusion of the patient's own T cells after ex vivo engineering to express CARs targeting tumor antigens and triggering T cell signaling. Here we describe the generation of REGN5458, a human bispecific antibody that binds to BCMA and CD3. In vitro, REGN5458 efficiently activates T cells and induces polyclonal T cell killing of myeloma cell lines with a range of BCMA cell-surface densities, and also induces cytotoxicity of primary human plasma cells. Similar to gamma-sectretase inhibitors, incubation of myeloma cell lines with REGN5458 increased surface levels of BCMA. In xenogenic studies, after BCMAhigh NCI-H929 and BCMAlow MOLP-8 MM cells were co-implanted with PBMC and grown subcutaneously in immunodeficient NOD/SCID/L2Rgamma-deficient (NSG) mice, REGN5458 doses as low as 0.4 mg/kg significantly suppressed the growth of both tumors. Using aggressive, systemic xenogenic tumor models, in which NSG mice were engrafted with PBMC and intravenously injected with BCMAhigh OPM-2 cells or BCMAlow MOLP-8 cells expressing luciferase, REGN5458 reduced tumor burden and suppressed tumor growth at doses as low as 0.4 mg/kg. In immunocompetent mice genetically engineered to express human CD3, REGN5458 inhibited the growth of syngeneic murine tumors expressing human BCMA at doses as low as 0.04 mg/kg. Finally, as REGN5458 binds to cynomolgus CD3 and BCMA and mediates cytotoxicity of primary cynomolgus plasma cells, the pharmacology of REGN5458 was evaluated in cynomolgus monkeys. REGN5458 administration was well-tolerated, resulting in a mild inflammatory response characterized by transiently increased CRP and serum cytokines. Importantly, REGN5458 treatment led to the depletion of BCMA+ plasma cells in the bone marrow, demonstrating cytotoxic activity in non-human primates. The anti-tumor efficacy of REGN5458 was compared to BCMA-specific CAR T cells using 2nd generation CAR lentiviral constructs containing a single-chain variable fragment binding domain from REGN5458's BCMA binding arm and 4-1BB and CD3z signaling domains. Human PBMC-derived T cells were transduced to express this CAR and expanded. Both REGN5458 and the BCMA CAR T cells demonstrated similar targeted cytotoxicity of myeloma cell lines and primary patient blasts in vitro, and were capable of clearing established systemic OPM-2-luciferase myeloma tumors in NSG mice, but with different kinetics: treatment with REGN5458 resulted in rapid clearance of tumors within 4 days, whereas treatment with BCMA CAR T cells allowed tumors to continue to grow for 10-14 days following injection before rapidly inducing tumor clearance. Thus, REGN5458 exerts its therapeutic effect rapidly after injection, using effector T cells that are already in place. In contrast, BCMA CAR T cells require time to traffic to the tumor site and expand, before exerting anti-tumor effects. Collectively, these data demonstrate the potent pre-clinical anti-tumor activity of REGN5458 that is comparable to that of CAR T cells, and provide a strong rationale for clinical testing of REGN5458 in patients with MM. Disclosures Dilillo: Regeneron Pharmaceuticals: Employment. Olson:Regeneron Pharmaceuticals: Employment. Mohrs:Regeneron Pharmaceuticals: Employment. Meagher:Regeneron Pharmaceuticals: Employment. Bray:Regeneron Pharmaceuticals: Employment. Sineshchekova:Regeneron Pharmaceuticals: Employment. Startz:Regeneron Pharmaceuticals: Employment. Retter:Regeneron Pharmaceuticals: Employment. Godin:Regeneron Pharmaceuticals: Employment. Delfino:Regeneron Pharmaceuticals: Employment. Lin:Regeneron Pharmaceuticals: Employment. Smith:Regeneron Pharmaceuticals: Employment. Thurston:Regeneron Pharmaceuticals: Employment. Kirshner:Regeneron Pharmaceuticals: Employment.

Transduction of Malignant Plasma Cells with Three Costimulatory Molecules (TRICOM) Elicits Myeloma-Specific Immune Response in Vitro – a Promising Strategy for Immunotherapy

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1908-1908
Author(s):  
Katarina Luptakova ◽  
Heidi Mills ◽  
Jacalyn Rosenblatt ◽  
Dina Stroopinsky ◽  
Turner Kufe ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Plasma Cells ◽  
Costimulatory Molecules ◽  
Cell Populations ◽  
Autologous Tumor

Abstract Abstract 1908 Introduction: Tumor vaccines hold promise as a means of eliciting anti-myeloma immunity and controlling disease that may be resistant to chemotherapy and biologic therapy. We have developed a whole cell tumor vaccine, whereby patient derived plasma cells are transduced with an attenuated vaccinia vector that contains transgenes for the costimulatory molecules B7.1 (CD80), ICAM-1 (CD54), and LFA-3 (CD58), designated TRIad of COstimulatory Molecules (TRICOM). In this manner, a broad array of tumor antigens, including those which may be specific to a given patient, are presented in the context of costimulatory molecules that have been shown to be synergistic in the stimulation of the effector T-cells. In the present study, we evaluated the phenotype and functional characteristics of TRICOM transduced primary myeloma cells. Methods and results: Plasma cells were isolated from bone marrow aspirates obtained from patients with multiple myeloma following Ficoll density centrifugation. Bone marrow derived mononuclear cells were infected with a replication-defective poxviral vector, the modified vaccinia Ankara strain (MVA), encoding TRICOM, or a control empty MVA vector. The expression of costimulatory molecules was assessed using flow cytometric analysis 3 hrs following viral infection. Viral transduction using the TRICOM vector at the dose of 20 MOI (multiplicity of infection) increased the mean percentage of CD38+ cells expressing CD80, CD54 and CD58 from a minimal baseline level (below 5%) to 70%, 56% and 47%, respectively (n=4). Transduction with control MVA vector did not augment expression of costimulatory molecules on plasma cells (mean percent expression of CD80, CD54 and CD58 of 2.6%, 2.7% and 3.8%, respectively, n=4). Of note, compared to CD38+ plasma cells, the CD38 negative fraction of bone marrow derived mononuclear cells demonstrated a significantly lower TRICOM transduction efficiency (mean percent expression of CD80, CD54 and CD58 of 16%, 17% and 16%, respectively, n=4, p<0.05 compared to CD38+ plasma cells). The ability of MVA-TRICOM transduced plasma cells to stimulate autologous T cell populations in vitro was assessed. Patient derived T-cells were purified from the non-adherent portion of PBMC by magnetic bead separation. MVA-TRICOM or empty MVA vector infected plasma cells were irradiated with 20Gy and co-cultured with autologous T cells at a 10:1 ratio of effector cells to vaccine for 7 days. MVA-TRICOM transduced plasma cells potently stimulated activated T cell responses, as assessed by the percentage of CD4+/CD25+/CD69+ T-cells (mean 7.8% of activated T-cells with TRICOM vaccine vs. 2.7% with control vaccine, n=3, p<0.05). In contrast, vaccine stimulation did not result in regulatory T-cell expansion, assessed as the percentage of cells co-expressing CD4,CD25 and FoxP3 (2.4% vs. 2.3%, for TRICOM and control vaccine, respectively, n=3). In concert with these findings, vaccine stimulation resulted in a polarization towards Th1 cytokine secretion, with 7.9% of CD4+ T-cells expressing intracellular IFN-γ after stimulation with TRICOM vaccine as compared to 5.4% after stimulation with the control vaccine (n=3, p<0.05). To further assess the expansion of tumor specific T cell populations, the ability of vaccine stimulated T cells to kill autologous tumor was assessed in a cell-based fluorogenic cytotoxicity assay. MVA-TRICOM transduced plasma cells potently stimulate the expansion of myeloma specific CTLs with the capacity to lyse autologous tumor targets. Mean CTL lysis was 20% and 8% for vaccine stimulated and unstimulated T cells respectively (n=2). Conclusions: Malignant plasma cells transduced with MVA-TRICOM strongly express costimulatory molecules, and potently stimulate activated, tumor reactive T cell populations. This preclinical data serves as a platform for developing a phase 1 clinical trial evaluating the use of MVA-TRICOM transduced autologous plasma cells in patients with multiple myeloma. Disclosures: No relevant conflicts of interest to declare.

Preclinical Evaluation of a Potent Anti-Bcma CD3 Bispecific Molecule for the Treatment of Multiple Myeloma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 383-383 ◽  
Author(s):  
Siler H Panowski ◽  
Tracy Kuo ◽  
Amy Chen ◽  
Tao Geng ◽  
Thomas J Van Blarcom ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Half Life ◽  
Plasma Cells ◽  
Target Cells ◽  
Dependent Manner ◽  
Human Igg

Abstract Multiple myeloma (MM) is a debilitating disease characterized by the abnormal accumulation of malignant plasma cells in the bone marrow. Despite recent advances in myeloma therapy, including proteasome inhibitors, immunomodulatory drugs, and targeted antibody therapies, patients relapse and the disease remains incurable and one of high unmet need. T cell redirecting therapies are a new and exciting class of therapeutics that harness the potent cytotoxic activity of T cells and redirect it to target tumor cells. T cell redirecting therapies are only as good as their targeted tumor associated antigen (TAA) and the potent nature of the therapy requires a lack of TAA expression in essential normal tissue. B-cell Maturation Antigen, BCMA, is a tumor necrosis factor superfamily member highly expressed on the surface of myeloma cells. Detectable normal BCMA tissue expression appears limited to plasmablasts and mature plasma cells, making it an ideal T cell redirecting target for the treatment of MM. Other groups have developed T cell redirecting therapies against BCMA, including CAR T and BiTE therapy (a short half-life CD3 bispecific). Here we present preclinical studies on a fully-human IgG CD3 bispecific molecule targeting BCMA (half-life in mice of ~3 days). This molecule utilizes anti-BCMA and anti-CD3 targeting arms paired through hinge mutation technology and placed in an IgG2A backbone. The molecule binds to BCMA-expressing myeloma cell lines and to T cells with affinities of 20pM and ~40nM, respectively. T cells co-cultured with MM cell lines were activated and de-granulated in the presence of BCMA bispecific. In vitro cytotoxicity assays revealed the high potency of the molecule, as it was able to drive lysis of MM target cells with an EC50 of 6± 8 pM (mean ± SD). We also observed strong in vitro potency with the BCMA bispecific in four different MM primary patient samples, EC50 =0.093±0.1 nM (mean ± SD). When the same four samples were targeted with a BCMA antibody drug conjugate (ADC), 3 of the samples gave EC50 values of 1.25±0.7 nM (mean ± SD) - i.e. a 43 fold decrease in potency compared to the CD3 bispecific. The fourth patient did not respond to the ADC. Together, these results illustrate the potential advantages of a CD3 bispecific over an ADC for targeting BCMA. In orthotopic, established, tumor mouse models utilizing three different MM cell lines, (OPM2, MM.1S and MOLP8), a single injection of BCMA bispecific effectively treated tumors in a dose-dependent manner. Re-dosing the bispecific was able to provide additional and prolonged efficacy. The extreme potency of T cell redirecting therapies results in outstanding efficacy, but can also lead to lysis of normal cells expressing even minute levels of target. The species cross-reactivity of the BCMA bispecific allowed for exploratory toxicity studies in cynomologus monkeys. The molecule was able to effectively deplete normal plasma B cells expressing low levels of BCMA, providing evidence of activity. Activity was accompanied by a cytokine spike following initial dosing. No cytokine release was observed following a second bispecific dose. Encouragingly, animals experienced no additional adverse events (AEs), confirming the favorable safety profile of BCMA as a target for MM. In summary, we report on a fully human IgG CD3 bispecific molecule targeting BCMA for the treatment of multiple myeloma. Our BCMA bispecific is expected to have an antibody-like half-life in humans and, taken together, our findings support that the molecule has the potential to be both a potent and safe therapeutic. Disclosures Panowski: Pfizer Inc.: Employment. Kuo:Alexo Therapeutics: Employment. Chen:Alexo Therapeutics: Employment. Geng:Kodiak Sciences: Employment. Van Blarcom:Pfizer Inc.: Employment. Lindquist:Pfizer Inc.: Employment. Chen:Pfizer Inc.: Employment. Chaparro-Riggers:Pfizer Inc.: Employment. Sasu:Pfizer Inc.: Employment.

Generation of T-cells reactive against CT-7 and BCMA peptides: Potential targets for T-cell immunotherapy of multiple myeloma

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 7615-7615
Author(s):  
L. D. Anderson ◽  
D. G. Maloney ◽  
S. R. Riddell
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Plasma Cell ◽  
Target Cells ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
T Cell Therapy

7615 Background: Multiple myeloma is a malignant plasma cell disorder that is incurable with chemotherapy or autologous stem cell transplantation (SCT), and novel therapies with lower toxicity are needed. There is evidence that T-cells can recognize myeloma and mediate anti-tumor effects, but the lack of defined target antigens other than idiotype has hindered the development of myeloma-specific T-cell therapy. We are investigating cancer-testis antigens and overexpressed “self”-proteins as candidate myeloma antigens, including MAGE-C1 (CT-7), which is expressed by >80% of myelomas, and B-Cell Maturation Antigen (BCMA), a plasma cell differentiation antigen commonly over-expressed in myeloma. Methods: To identify potential T-cell epitopes from CT-7 and BCMA, we scanned the protein sequences with computer algorithms and synthesized peptides predicted to bind to HLA-A2 and A3. CT-7 and BCMA are both “self” proteins to which the T-cell repertoire may be relatively tolerant, so we have utilized culture conditions that facilitate the expansion of rare myeloma-reactive T-cells. CD8+ T cells were stimulated in vitro with autologous dendritic cells pulsed with CT-7 or BCMA peptides in the presence of cytokines that avoid excessive nonspecific expansion of T-cells. Wells were screened for reactivity against peptide-pulsed target cells and myeloma cell lines. Results: A specific CD8+ T-cell response by both ELISPOT and cytotoxicity assays to at least one HLA-A2 peptide from each of the CT-7 and BCMA proteins has been identified in normal donors. CT-7 and BCMA-specific T-cells are being cloned in order to determine their ability to recognize primary myeloma cells. Experiments are also in progress to elicit responses to these peptides in myeloma patient samples and to screen HLA A3-binding epitopes. Conclusions: T-cells recognizing CT-7 and BCMA are detectable in the normal T-cell repertoire and can be isolated and expanded in vitro. We are currently pursuing the identification of additional antigenic epitopes in these proteins to define their potential utility as targets for vaccination or adoptive T-cell therapy. No significant financial relationships to disclose.

Development of a fully human T cell engaging bispecific antibody for the treatment of multiple myeloma.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 8017-8017 ◽  
Author(s):  
Ben Buelow ◽  
Duy Pham ◽  
Starlynn Clarke ◽  
Shelley Force Aldred ◽  
Kevin Dang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bispecific Antibody ◽  
Plasma Cells ◽  
Bispecific Antibodies ◽  
Human Pbmcs

8017 Background: Although BCMA is a plasma cell specific surface molecule attractive as an antibody target in multiple myeloma, its scarcity on the cell surface may limit the efficacy of a conventional antibody. T-cell engaging bispecific antibody approaches are highly efficacious and are particularly well suited for a membrane target with limited expression, such as BCMA. Teneobio has developed a multivalent antibody platform based on modular human VH domains, which allowed us to build T cell engaging bispecific antibodies with low and high T cell agonistic activities. Methods: UniRats were immunized with either CD3 or BCMA antigens and antigen-specific UniAbs were identified by antibody repertoire sequencing and high-throughput gene assembly, expression, and screening. High affinity binding VH sequences were selected using recombinant proteins and cells. In vitro efficacy studies included T-cell activation by cytokine- and tumor cell kill by calcein-release assays. In vivo efficacy of the molecules was evaluated in NSG mice harboring myeloma cells and human PBMCs. Results: BCMA-specific UniAbs bound plasma cells with high affinities (100-700pM) and cross-reacted with cynomolgus plasma cells. Strong and weak T cell agonists were identified that bound human T cells with high and low affinities respectively and cross-reacted with cynomolgus T cells. T cell engaging bispecifics with a strong (H929 cytotoxicity:EC50=27pM) and a weak T cell activating arm (H929 cytotoxicity: EC50=1170pM) demonstrated T-cell activation and tumor-cell cytotoxicity in vitro; bispecifics with a weak CD3 engaging arm showed markedly reduced cytokine production even at doses saturating for cytotoxicity. In viv o, BCMAxCD3 bispecific antibodies reduced tumor load and increased survival when co-administered with human PBMCs as compared to controls. Conclusions: Our results suggest that T cell engaging bispecifics with low-affinity anti-CD3 arms could be preferred for the treatment of Multiple Myeloma.

Wogonin preferentially kills malignant lymphocytes and suppresses T-cell tumor growth by inducing PLCγ1- and Ca2+-dependent apoptosis

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2354-2363 ◽  
Author(s):  
Sven Baumann ◽  
Stefanie C. Fas ◽  
Marco Giaisi ◽  
Wolfgang W. Müller ◽  
Anette Merling ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Therapeutic Potential ◽  
Human T Cell ◽  
Voltage Dependent ◽  
Ca2 Channels ◽  
Malignant T Cells

Herbs have successfully been used in traditional Chinese medicine for centuries. However, their curative mechanisms remain largely unknown. In this study, we show that Wogonin, derived from the traditional Chinese medicine Huang-Qin (Scutellaria baicalensis Georgi), induces apoptosis in malignant T cells in vitro and suppresses growth of human T-cell leukemia xenografts in vivo. Importantly, Wogonin shows almost no toxicity on T lymphocytes from healthy donors. Wogonin induces prolonged activation of PLCγ1 via H2O2 signaling in malignant T cells, which leads to sustained elevation of cytosolic Ca2+ in malignant but not normal T cells. Subsequently, a Ca2+ overload leads to disruption of the mitochondrial membrane. The selective effect of Wogonin is due to its differential regulation of the redox status of malignant versus normal T cells. In addition, we show that the L-type voltage-dependent Ca2+ channels are involved in the intracellular Ca2+ mobilization in T cells. Furthermore, we show that malignant T cells possess elevated amounts of voltage-dependent Ca2+ channels compared with normal T cells, which further enhance the cytotoxicity of Wogonin for malignant T cells. Taken together, our data show a therapeutic potential of Wogonin for the treatment of hematologic malignancies.

scholarly journals Development of Stable Chimeric IL-15 for Trans-Presentation by the Antigen Presenting Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Manoj Patidar ◽  
Naveen Yadav ◽  
Sarat K. Dalai
Keyword(s):  
T Cells ◽  
T Cell ◽  
Half Life ◽  
Therapeutic Potential ◽  
Chimeric Protein ◽  
Antigen Presenting Cells ◽  
T Cell Response ◽  
Antigen Presenting

IL-15 is one of the important biologics considered for vaccine adjuvant and treatment of cancer. However, a short half-life and poor bioavailability limit its therapeutic potential. Herein, we have structured IL-15 into a chimeric protein to improve its half-life enabling greater bioavailability for longer periods. We have covalently linked IL-15 with IgG2 base to make the IL-15 a stable chimeric protein, which also increased its serum half-life by 40 fold. The dimeric structure of this kind of IgG based biologics has greater stability, resistance to proteolytic cleavage, and less frequent dosing schedule with minimum dosage for achieving the desired response compared to that of their monomeric forms. The structured chimeric IL-15 naturally forms a dimer, and retains its affinity for binding to its receptor, IL-15Rβ. Moreover, with the focused action of the structured chimeric IL-15, antigen-presenting cells (APC) would transpresent chimeric IL-15 along with antigen to the T cell, that will help the generation of quantitatively and qualitatively better antigen-specific memory T cells. In vitro and in vivo studies demonstrate the biological activity of chimeric IL-15 with respect to its ability to induce IL-15 signaling and modulating CD8+ T cell response in favor of memory generation. Thus, a longer half-life, dimeric nature, and anticipated focused transpresentation by APCs to the T cells will make chimeric IL-15 a super-agonist for memory CD8+ T cell responses.

scholarly journals WT1 Tumor Antigen is Overexpressed in Kaposi Sarcoma and is Regulated by KSHV vFLIP

2021 ◽  
Author(s):  
Ayana Morales ◽  
Caitlyn Genovese ◽  
Matthew Bott ◽  
Julio Alvarez ◽  
Sung Soo Mun ◽  
...  
Keyword(s):  
T Cell ◽  
Therapeutic Approach ◽  
Poor Prognosis ◽  
Wilms Tumor ◽  
Kaposi Sarcoma ◽  
Host Protein ◽  
People Living With Hiv ◽  
Potential Biomarker ◽  
Wilms Tumor 1

AbstractPurposeWilms’ tumor 1 (WT1) is overexpressed in several cancers, and WT1 expression levels are associated with poor prognosis. As a host protein that functions as an oncogene, it represents an important immunotherapeutic target. This study evaluated WT1 expression in Kaposi sarcoma (KS) tumors to assess whether immunotherapy targeting WT1 is a potential therapeutic approach for KS. We also investigated the role of the causal agent of KS, Kaposi sarcoma herpesvirus (KSHV/HHV-8) in regulating WT1 expression.Experimental designImmunohistochemistry for WT1, KSHV, and B and T cells subsets, followed by image analysis, was performed in 363 KS tumor biopsies. Expression of KSHV vFLIP was evaluated by immunofluorescence. Primary endothelial cell cultures and cell lines were infected with KSHV in vitro, or transduced with an inducible vFLIP vector and induced with doxycycline, and then assessed for WT1 expression. Binding of ESK-1, a T cell receptor mimic therapeutic antibody that recognizes WT1 peptides presented on MHC HLA-A0201, was assessed using flow cytometry.ResultsWe report overexpression of WT1 in KS tumors, which was associated with increased with increasing histopathologic stage and the proportion of KSHV-infected cells. Areas with high WT1 expression showed sparse T cell infiltrates. KSHV infection in vitro resulted in WT1 upregulation, mediated by the viral protein vFLIP, which resulted in stronger binding of ESK1.ConclusionsKS lesions express high levels of WT1, a process regulated by the KSHV-encoded vFLIP. These findings suggest that immunotherapy directed against WT1 may represent a therapeutic approach for this cancer.Translational RelevanceKaposi sarcoma (KS) is a vascular neoplasm caused by the Kaposi sarcoma herpesvirus (KSHV/HHV-8). People living with HIV are not only at a significantly higher risk of developing KS, but also often have a more aggressive clinical course. Although antiretroviral therapy may cause regression of HIV-associated KS lesions, advanced cases of KS also require chemotherapy, which is rarely curative. Wilms’ tumor 1 (WT1) has been reported to be overexpressed in various cancers, functioning as an oncogene and associated with a poor prognosis. WT1 is also an important immunotherapeutic target, with several WT1-directed therapies showing promising results in early clinical trials for leukemias and solid tumors. Here we report high expression of WT1 in KS, especially in higher histological stages. Our findings provide pre-clinical evidence that supports conducting anti-WT1 immunotherapy trials in KS, and evaluating WT1 expression as a potential biomarker to identify individuals most likely to benefit.

scholarly journals A novel BCMA/CD3 bispecific T-cell engager for the treatment of multiple myeloma induces selective lysis in vitro and in vivo

Leukemia ◽  
2016 ◽  
Vol 31 (8) ◽  
pp. 1743-1751 ◽  
Author(s):  
S Hipp ◽  
Y-T Tai ◽  
D Blanset ◽  
P Deegen ◽  
J Wahl ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cell ◽  
Plasma Cells ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Selective Lysis ◽  
Bispecific T Cell Engager

Abstract B-cell maturation antigen (BCMA) is a highly plasma cell-selective protein that is expressed on malignant plasma cells of multiple myeloma (MM) patients and therefore is an ideal target for T-cell redirecting therapies. We developed a bispecific T-cell engager (BiTE) targeting BCMA and CD3ɛ (BI 836909) and studied its therapeutic impacts on MM. BI 836909 induced selective lysis of BCMA-positive MM cells, activation of T cells, release of cytokines and T-cell proliferation; whereas BCMA-negative cells were not affected. Activity of BI 836909 was not influenced by the presence of bone marrow stromal cells, soluble BCMA or a proliferation-inducing ligand (APRIL). In ex vivo assays, BI 836909 induced potent autologous MM cell lysis in both, newly diagnosed and relapsed/refractory patient samples. In mouse xenograft studies, BI 836909 induced tumor cell depletion in a subcutaneous NCI-H929 xenograft model and prolonged survival in an orthotopic L-363 xenograft model. In a cynomolgus monkey study, administration of BI 836909 led to depletion of BCMA-positive plasma cells in the bone marrow. Taken together, these results show that BI 836909 is a highly potent and efficacious approach to selectively deplete BCMA-positive MM cells and represents a novel immunotherapeutic for the treatment of MM.

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