T Cell Receptor Gene Therapy Targeting the Intracellular Transcription Factor Bob1 for the Treatment of Multiple Myeloma and Other B Cell Malignancies

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3002-3002 ◽  
Author(s):  
Lorenz Jahn ◽  
Renate S. Hagedoorn ◽  
Pleun Hombrink ◽  
Michel G.D. Kester ◽  
Dirk M. van der Steen ◽  
...  

Abstract Therapeutic reactivity of CD20-specific monoclonal antibodies (mAb) or CD19-specific chimeric antigen receptor (CAR)-transduced T cells is exerted by targeting extracellular antigens. In contrast to mAbs and CARs, T cell receptors (TCRs) recognize antigen-derived peptides that are bound to human leukocyte antigen (HLA) molecules on the cell surface. Since HLA molecules constantly sample the entire endogenous proteome of a cell, extracellular and intracellular antigens are presented and can thus be recognized by a TCR. Here, we identified the intracellular transcription factor Bob1 encoded by gene POU2AF1 as a suitable target for immunotherapy. Bob1 is highly expressed in CD19+ B cells, acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL) and multiple myeloma (MM) and is absent in the non-B lineages including CD34+ hematopoietic progenitor cells (HPCs), T cells, fibroblasts, keratinocytes and gastrointestinal tract. Bob1 is localized intracellularly but HLA-presented Bob1-derived peptides are accessible on the cell surface to TCRs and can thus be recognized by T cells. From the HLA-presented ligandome (Mol Cell Proteomics, 2013;12:1829) we identified naturally processed Bob1-derived peptides displayed in HLA-A*0201 (HLA-A2) and in HLA-B*0702 (HLA-B7). Since auto-reactivity towards self-antigens such as Bob1 is prevented by depleting high-avidity T cells recognizing self-antigens in self-HLA, we exploited the immunogenicity of these peptides presented in allogeneic HLA. From a HLA-A2/B7-negative healthy individual we isolated T cell clone 4G11 demonstrating high sensitivity and specificity for Bob1-derived peptide Bob144 presented in HLA-B7. Bob1-dependent recognition was demonstrated by transduction of Bob1 into cell lines that otherwise lack Bob1 expression. No harmful toxicities of clone 4G11 were observed against a wide panel of Bob1-negative stimulator cells including HLA-B7-positive CD34+ HPCs, T cells, monocytes, immature and mature dendritic cells, and fibroblasts even under simulated inflamed conditions. Furthermore, stringent HLA-B7-restricted recognition was observed for clone 4G11 when tested against a stimulator panel expressing a wide range of common and rare HLA class I and II molecules. Clone 4G11 demonstrated clinical applicability by efficiently recognizing HLA-B7+ primary ALL, CLL and MCL. Furthermore, reproducible strong recognition of purified primary HLA-B7+ MM could be demonstrated. Therefore, the TCR of clone 4G11 may be used for immunotherapy by administering TCR-transduced T cells to patients suffering from B cell malignancies including multiple myeloma. Retroviral gene transfer of TCR 4G11 led to efficient cell surface expression demonstrated by binding of TCR-transduced CD8+ T cells to pMHC-tetramer composed of peptide Bob144 bound to HLA-B7. TCR-modified CD8+ T cells strongly recognized Bob1-expressing HLA-B7+ multiple myeloma cell lines U266 and UM9, and ALL cell lines. TCR-modified T cells efficiently lysed HLA-B7+ primary ALL, CLL and MCL at very low effector-to-target ratios. In addition, highly purified primary multiple myeloma samples were also readily lysed. Furthermore, TCR-transduced T cells strongly proliferated in an antigen-specific manner when stimulated with primary malignant cell samples including ALL, CLL, and MCL or MM cell lines. As expected, TCR-transduced T cells also lysed autologous primary and CD40L-stimulated B cells since these targets cells also express Bob1. In contrast, no lysis of Bob1-negative autologous primary and activated T cells, or monocytes was observed when co-cultured with TCR-transduced T cells. In summary, we identified the intracellular transcription factor Bob1 encoded by gene POU2AF1 as a suitable target for TCR-based immunotherapies of B cell malignancies. Bob1-specific T cell clone 4G11 efficiently recognized primary B cell leukemia and multiple myeloma. Gene transfer of TCR of clone 4G11 installed Bob1-reactivity and specificity onto recipient T cells shown here by cytolytic capacity and proliferation upon antigen encounter. TCR gene transfer approaches using this Bob1-specific TCR can bring novel treatment modalities and possibly curative therapy to patients with B cell malignancies including multiple myeloma. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3832-3832 ◽  
Author(s):  
Lorenz Jahn ◽  
Pleun Hombrink ◽  
Michel G.D. Kester ◽  
Dirk M. van der Steen ◽  
Renate S. Hagedoorn ◽  
...  

Abstract Therapeutic reactivity of CD20-specific monoclonal antibodies (mAb) or CD19-specific chimeric antigen receptor (CAR)-transduced T cells is exerted by targeting extracellular antigens. However, loss of CD20 and CD19 expression or absence of these molecules on other malignancies such as multiple myeloma restricts their application. Here, we identified the intracellular transcription factor Bob1 encoded by gene POU2AF1 as a suitable target for immunotherapy. Bob1 is highly expressed in CD19+ B cells, acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL) and multiple myeloma (MM) and is absent in the non-B lineages including CD34+ hematopoietic progenitor cells (HPCs), T cells, fibroblasts, keratinocytes and gastrointestinal tract. Bob1 is localized intracellularly but HLA-presented Bob1-derived peptides are accessible on the cell surface to T cell receptors (TCRs) and can thus be recognized by T cells. From the HLA-presented ligandome (Mol Cell Proteomics, 2013;12:1829) we identified naturally processed Bob1-derived peptides displayed in HLA-A*0201 (HLA-A2) and in HLA-B*0702 (HLA-B7). Since auto-reactivity towards self-antigens such as Bob1 is prevented by depleting high-avidity T cells recognizing self-antigens in self-HLA, we exploited the immunogenicity of these peptides presented in allogeneic HLA. From a total of 3 x 109 peripheral blood mononuclear cells from 6 different HLA-A2/B7-negative healthy donors, we isolated and clonally expanded more than 1000 CD8+ T cells binding to peptide-MHC-tetramers composed of the Bob1-derived peptides bound to HLA-A2 or HLA-B7. The T cell clones were tested for stringent peptide-specificity by stimulation with Bob1-negative K562 cells expressing either HLA-A2 or B7 unloaded or pulsed with Bob1-derived peptides. This resulted in the selection of 15 T cell clones highly specific for Bob1. To identify the T cell clones of highest avidity, T cell clones were compared for peptide-sensitivity by testing the recognition of stimulator cells loaded with titrated amounts of Bob1-derived peptides and of Bob1-expressing HLA-A2/B7-positive EBV-transformed B cells. T cell clone 4G11 was selected because of high sensitivity and specificity for Bob1-derived peptide Bob144 presented in HLA-B7 and T cell clone 3C10 specifically recognized peptide Bob1245 bound to HLA-A2. Bob1-dependent recognition was demonstrated by transduction of Bob1 into cell lines that otherwise lack Bob1 expression. To investigate whether harmful toxicities could be caused by these T cell clones, we tested their reactivity against a wide panel of Bob1-negative stimulator cells demonstrating absence of recognition of HLA-B7-positive CD34+ HPCs, T cells, monocytes, immature and mature dendritic cells, and fibroblasts even under simulated inflamed conditions. Stringent HLA-B7-restricted recognition was observed for clone 4G11 when tested against a stimulator panel expressing a wide range of common and rare HLA class I and II molecules. These data illustrate a safe reactivity profile with little chance of off-target toxicity. To test their clinical applicability, clone 4G11 and 3C10 were tested for recognition of various primary B cell malignancies. Clone 4G11 efficiently recognized HLA-B7-positive primary ALL, CLL and mantle cell lymphoma while clone 3C10 recognized HLA-A2-positive primary B cell malignancies albeit to a lesser degree. Furthermore, reproducible strong recognition of purified primary HLA-B7-positive multiple myeloma could be demonstrated for clone 4G11. Therefore, T cell clone 4G11’s TCR may be used for immunotherapy by administering TCR-transduced T cells to multiple myeloma patients. To test whether introduction of 4G11’s TCR confers Bob1-reactivity onto recipient cells, the TCR was cloned into a retroviral vector. Highly specific reactivity against HLA-B7-positive Bob1-expressing target cells could be installed to TCR-transduced recipient T cells. In summary, we identified the intracellular transcription factor Bob1 encoded by gene POU2AF1 as a suitable target for TCR-based immunotherapies of B cell malignancies and multiple myeloma. Bob1-specific T cell clone 4G11 efficiently recognized primary B cell leukemia and multiple myeloma. TCR gene transfer approaches using Bob1-specific TCRs can bring novel treatment modalities for patients with B cell malignancies or multiple myeloma. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3078-3078
Author(s):  
Diane L Rossi ◽  
Edmund A Rossi ◽  
David M Goldenberg ◽  
Chien-Hsing Chang

Abstract Background Various formats of bispecific antibodies (bsAbs) to redirect effector T cells for the targeted killing of tumor cells have shown considerable promise both pre-clinically and clinically. The scFv-based constructs, including BiTE and DART, which bind monovalently to CD3 on T cells and to the target antigen on tumor cells, exhibit fast blood clearance and neurological toxicity due to their small size (∼55 kDa). Herein, we describe the generation of novel T-cell redirecting trivalent bsAbs comprising an anti-CD3 scFv covalently conjugated to a stabilized F(ab)2. The design was initially characterized with a prototype construct designated (19)-3s, which specifically targets CD19 on B cells. A panel of trivalent bsAbs was evaluated for their potential use in targeted T-cell immunotherapy of various B-cell malignancies. Potential advantages of this design include bivalent binding to tumor cells, a larger size (∼130 kDa) to preclude rapid renal clearance and penetration of the blood-brain barrier, and potent T-cell mediated cytotoxicity. Methods The DOCK-AND-LOCKTM (DNLTM) method was used to generate a panel of B-cell targeting bsAbs, (19)-3s, (20)-3s, (22)-3s, and (C2)-3s, which target CD19, CD20, CD22, and HLA-DR, respectively. This was achieved by combining a stabilized anti-X F(ab)2 with an anti-CD3-scFv, resulting in a homogeneous covalent structure of the designed composition, as shown by LC-MS, SE-HPLC, ELISA, SDS-PAGE, and immunoblot analyses. Each construct can mediate the formation of immunological synapses between T cells and malignant B cells, resulting in T-cell activation. At an E:T ratio of 10:1, using isolated T cells as effector cells, the bsAbs induced potent T-cell-mediated cytotoxicity in various B-cell malignancies, including Burkitt lymphomas (Daudi, Ramos, Namalwa), mantle cell lymphoma (Jeko-1), and acute lymphoblastic leukemia (Nalm-6). A non-tumor binding control, (14)-3s, induced only moderate T-cell killing at >10 nM. The nature of the antigen/epitope, particularly its size and proximity to the cell surface, appears to be more important than antigen density for T-cell retargeting potency (Table 1). It is likely that (20)-3s is consistently more potent than (19)-3s and (C2)-3s, even when the expression of CD19 or HLA-DR is considerably higher than CD20, as seen with Namalwa and Jeko-1, respectively. This is likely because the CD20 epitope comprises a small extracellular loop having close proximity to the cell surface. When compared directly using Daudi, (22)-3s was the least potent. Compared to CD19 and CD20, CD22 is expressed at the lowest density, is a rapidly internalizing antigen, and its epitope is further away from the cell surface; each of these factors may contribute to its reduced potency. Finally, sensitivity to T-cell retargeted killing is cell-line-dependent, as observed using (19)-3s, where Raji (IC50 >3 nM) is largely unresponsive yet Ramos (IC50 = 2 pM) is highly sensitive, even though the former expresses higher CD19 antigen density. Conclusions (19)-3s, (20)-3s, (22)-3s, and (C2)-3s can bind T cells and target B cells simultaneously and induce T-cell-mediated killing in vitro. The modular nature of the DNL method allowed the rapid production of several related conjugates for redirected T-cell killing of various B-cell malignancies, without the need for additional recombinant engineering and protein production. The close proximity of the CD20 extracellular epitope to the cell surface results in the highest potency for (20)-3s, which is an attractive candidate bsAb for use in this platform. We are currently evaluating the in vivo activity of these constructs to determine if this novel bsAb format offers additional advantages. Disclosures: Rossi: Immunomedics, Inc.: Employment. Rossi:Immunomedics, Inc.: Employment. Goldenberg:Immunomedics: Employment, stock options, stock options Patents & Royalties. Chang:Immunomedics, Inc: Employment, Stock option Other; IBC Pharmaceuticals, Inc.: Employment, Stock option, Stock option Other.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 506-506 ◽  
Author(s):  
Carlos A. Ramos ◽  
Barbara Savoldo ◽  
Enli Liu ◽  
Adrian P. Gee ◽  
Zhuyong Mei ◽  
...  

Abstract Adoptive transfer of T cells with a CD19-specific chimeric antigen receptor (CAR) to treat B-cell malignancies shows remarkable clinical efficacy. However, long-term persistence of T cells targeting CD19, a pan-B cell marker, causes sustained depletion of normal B cells and consequent severe hypogammaglobulinemia. In order to target B-cell malignancies more selectively, we exploited the clonal restriction of mature B-cell malignancies, which express either a κ or a λ-light immunoglobulin (Ig) chain. We generated a CAR specific for κ-light chain (CAR.κ) to selectively target κ+ lymphoma/leukemia cells, while sparing the normal B cells expressing the reciprocal λ-light chain, thus minimizing the impairment of humoral immunity. After preclinical validation, we designed a phase I clinical trial in which patients with refractory/relapsed κ+ non-Hodgkin lymphoma (NHL) or chronic lymphocytic leukemia (CLL) are infused with autologous T cells expressing a CAR.κ that includes a CD28 costimulatory domain. The protocol also included patients with multiple myeloma with the aim of targeting putative myeloma initiating cells. Three dose levels (DL) are being assessed, with escalation determined by a continual reassessment method: 0.2 (DL1), 1 (DL2) and 2 (DL3) ×108 T cells/m2. Repeat infusions are allowed if there is at least stable disease after treatment. End points being evaluated include safety, persistence of CAR+T cells and antitumor activity. T cells were generated for 13 patients by activating autologous PBMC with immobilized OKT3 (n=5) or CD3/CD28 monoclonal antibodies (n=8). In 2 patients with >95% circulating leukemic cells, CD3 positive selection was performed using CliniMACS. After transduction, T cells (1.2×107±0.5×107) were expanded ex vivo for 18±4 days in the presence of interleukin (IL)-2 to reach sufficient numbers for dose escalation. CAR expression was 81%±13% by flow cytometry (74,112±23,000 transgene copy numbers/mg DNA). Products were composed predominantly of CD8+ cells (78%±10%), with a small proportion of naïve (5±4%) and memory T cells (17%±12%). CAR+ T cells specifically targeted κ+ tumors as assessed by 51Cr release assays (specific lysis 79%±10%, 20:1 E:T ratio) but not κ–tumors (11%±7%) or the NK-sensitive cell line K562 (26%±13%). Ten patients have been treated: 2 on DL1, 3 on DL2 and 5 on DL3. Any other treatments were discontinued at least 4 weeks prior to T-cell infusion. Patients with an absolute leukocyte count >500/µL received 12.5 mg/kg cyclophosphamide 4 days before T-cell infusion to induce mild lymphopenia. Infusions were well tolerated, without side effects. Persistence of infused T cells was assessed in blood by CAR.κ-specific Q-PCR assay and peaked 1 to 2 weeks post infusion, remaining detectable for 6 weeks to 9 months. Although the CAR contained a murine single-chain variable fragment (scFv), we did not detect human anti-mouse antibodies following treatment and CAR.κ+T cell expansion continued to be observed even after repeated infusions. We detected modest (<20 fold) elevation of proinflammatory cytokines, including IL-6, at the time of peak expansion of T cells, but systemic inflammatory response syndrome (cytokine storm) was absent. No new-onset hypogammaglobulinemia was observed. All 10 patients are currently evaluable for clinical response. Of the patients with relapsed NHL, 2/5 entered complete remission (after 2 and 3 infusions at dose level 1 and 3, respectively), 1/5 had a partial response and 2 progressed; 3/3 patients with multiple myeloma have had stable disease for 2, 8 and 11 months, associated with up to 38% reduction in their paraprotein; and 2/2 patients with CLL progressed before or shortly after the 6-week evaluation. In conclusion, our data indicate that infusion of CAR.κ+ T cells is safe at every DL and can be effective in patients with κ+ lymphoproliferative disorders. Disclosures: Savoldo: Celgene: Patents & Royalties, Research Funding. Rooney:Celgene: Patents & Royalties, Research Funding. Heslop:Celgene: Patents & Royalties, Research Funding. Brenner:Celgene: Patents & Royalties, Research Funding. Dotti:Celgene: Patents & Royalties, Research Funding.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 308-308
Author(s):  
Sara Mastaglio ◽  
Pietro Genovese ◽  
Zulma Magnani ◽  
Elisa Landoni ◽  
Barbara Camisa ◽  
...  

Abstract Background. Gene transfer of T cell receptors (TCR) specific for tumor associated antigens is a promising approach of adoptive immunotherapy for cancer patients. However, T cells transduced with an exogenous TCR, have proved less effective than naturally occurring tumor specific T cells, with suboptimal clinical results. This could be due to the dilution of the tumor specific TCR that competes with endogenous TCRs for its expression on the T cell surface. Moreover, mispairing between endogenous and exogenous TCR a and b chains could generate new TCRs with unpredictable and potentially harmful specificities. To overcome these issues, our group developed a TCR gene editing procedure, based on the knockout of the endogenous TCR genes by transient exposure to a and b chain specific Zinc Finger Nucleases (ZFNs), followed by the introduction of tumor-specific TCR genes by lentiviral vectors (Provasi, Genovese et al, Nature Medicine 2102). The complete editing procedure requires multiple manipulation steps involving repeated cell activation cycles and four transduction procedures. Conversely, ‘single TCR editing’ (SE), based on the disruption of a single endogenous TCR chain, followed by transfer of the tumor specific TCR, generates redirected T cells fully devoid of their natural TCR repertoire, in a single round of cell activation. The aim of this project is to determine the efficacy and safety profile of SE T cells in vitro and in vivo. Results. We validated the SE protocol exploiting an HLA-A2 restricted TCR specific for the cancer testis antigen NY-ESO-1157-165 peptide. NY-ESO-1 is highly expressed by a large number of solid tumors and by the majority of monoclonal plasma cells of patients affected by high risk multiple myeloma, while its expression in healthy tissues is restricted to testicular germ cells. T cells harvested from healthy donors were activated with CD3/CD28 conjugated beads and cultured with low doses of IL7 and IL15. Two days after activation ZFNs were transiently delivered to T cells by mRNA transfection or by infection with adenoviral vectors, with similar efficacy. Sorted CD3- T cells were transduced at day 8 with a bidirectional lentiviral vector encoding both the a and b chains of the NY-ESO-1-specific TCR. The SE strategy allowed the rapid production of high numbers of extremely fit tumor specific T cells, enriched for cells with an early differentiated phenotype (CD45RA+/CD62L+/CD95+, namely stem memory T cells). NY-ESO-1 TCR expression, investigated through dextramer specific binding, was significantly higher in SE than in T cells undergoing TCR gene transfer (TR). To test the efficacy of NY-ESO-1 redirected T cells we took advantage of the NY-ESO-1+HLA-A2+ U266 myeloma cell line. When tested against U266 cells in different assays (co-cultures, g-IFN and 51Cr release), all NY-ESO-1 redirected T cells showed a strikingly high killing potential. However, when we compared the alloreactive potential of the different NY-ESO-1 specific T cell populations in mixed lymphocyte reactions against completely mismatched allogeneic targets, we interestingly observed that the lysis of the allogeneic target by TR cells was significantly higher than that of SE T cells (p=0.05). This suggests that the residual endogenous polyclonal TCRs and possibly mispaired TCRs expressed on the cell surface of TR T cells can lead to off-target recognition, while SE T cells are devoid of such reactivity. These results were validated in NSG mice, engrafted with U266 cells and subsequently infused with NY-ESO-1 specific T cells. All animals treated with tumor specific T cells were completely disease free at the time of sacrifice, demonstrating the powerful anti-tumor potential of the NY-ESO-1 TCR. However, a substantial proportion of mice administered with TR cells suffered from xenogeneic chronic graft versus host disease (GvHD), while all animals treated with SE T cells remained free of GvHD throughout the course of the study. Discussion. The single gene editing protocol enables the rapid generation of clinically relevant doses of highly performing tumor specific T cells, fully devoid of their endogenous TCR repertoire, and thus particularly appealing for a future clinical translation. Donor-derived SE T cells, with a significantly reduced alloreactive potential, could be especially suitable to treat patients with minimal residual disease after allogeneic hematopoietic stem cell transplantation. Disclosures Reik: Sangamo Bioscience: Employment. Holmes:Sangamo Bioscience: Employment. Gregory:Sangamo Bioscience: Employment.


Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2523
Author(s):  
Robert J. Cronk ◽  
Joanna Zurko ◽  
Nirav N. Shah

Chimeric antigen receptor (CAR) modified T cell therapy offers a targeted immunotherapeutic approach to patients with refractory hematological malignancies. This technology is most advanced in B cell malignancies and multiple myeloma and is rapidly evolving as more data become available regarding clinical efficacy and response durability. Despite excellent initial response rates with single antigen targeting CARs, failure to respond to therapy and relapse due to target antigen downregulation remain clinical challenges. To mitigate immunophenotypic selective pressures, simultaneous dual antigen targeting with bispecific CAR T cells or multiple administration of different populations of CAR T cells may prevent relapse by addressing one resistance mechanism attributed to antigenic loss. This article will review recently published data on the use of dual targeting with CAR T cells from early phase clinical trials aimed at treating B cell malignancies and multiple myeloma.


1983 ◽  
Vol 1 (12) ◽  
pp. 810-816 ◽  
Author(s):  
N E Kay ◽  
M M Oken ◽  
R T Perri

Investigations of human B-cell malignancies have generally focused on the monoclonal B-cell populations. Until recently there has been little emphasis on the thymus (T) lymphocyte in these disorders. Current studies, however, suggest that quantitative and qualitative disorders of T cells are generally seen both in chronic lymphocytic leukemia and in multiple myeloma. This review will focus on two major concepts. First, it will define the quantitative and functional T-cell abnormalities in B-cell malignancies including evidence suggesting a causal link between the T-cell abnormalities and certain observed disease manifestations in chronic lymphocytic leukemia and multiple myeloma. Secondly, it will review data demonstrating that these T cells may be influenced by in vivo and in vitro manipulations and will outline some of the possible resultant clinical effects.


2021 ◽  
Vol 9 (7) ◽  
pp. e002410
Author(s):  
Özcan Çınar ◽  
Bernadette Brzezicha ◽  
Corinna Grunert ◽  
Peter Michael Kloetzel ◽  
Christin Beier ◽  
...  

BackgroundAdoptive transfer of engineered T cells has shown remarkable success in B-cell malignancies. However, the most common strategy of targeting lineage-specific antigens can lead to undesirable side effects. Also, a substantial fraction of patients have refractory disease. Novel treatment approaches with more precise targeting may be an appealing alternative. Oncogenic somatic mutations represent ideal targets because of tumor specificity. Mutation-derived neoantigens can be recognized by T-cell receptors (TCRs) in the context of MHC–peptide presentation.MethodsHere we have generated T-cell lines from healthy donors by autologous in vitro priming, targeting a missense mutation on the adaptor protein MyD88, changing leucine at position 265 to proline (MyD88 L265P), which is one of the most common driver mutations found in B-cell lymphomas.ResultsGenerated T-cell lines were selectively reactive against the mutant HLA-B*07:02-restricted epitope but not against the corresponding wild-type peptide. Cloned TCRs from these cell lines led to mutation-specific and HLA-restricted reactivity with varying functional avidity. T cells engineered with a mutation-specific TCR (TCR-T cells) recognized and killed B-cell lymphoma cell lines characterized by intrinsic MyD88 L265P mutation. Furthermore, TCR-T cells showed promising therapeutic efficacy in xenograft mouse models. In addition, initial safety screening did not indicate any sign of off-target reactivity.ConclusionTaken together, our data suggest that mutation-specific TCRs can be used to target the MyD88 L265P mutation, and hold promise for precision therapy in a significant subgroup of B-cell malignancies, possibly achieving the goal of absolute tumor specificity, a long sought-after dream of immunotherapy.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 265-265
Author(s):  
Francesco Di Meo ◽  
Christina Yu ◽  
Annamaria Cesarano ◽  
Aljoufi Arafat ◽  
Silvia Marino ◽  
...  

Abstract Multiple myeloma (MM) is an incurable malignancy of mature plasma cells. Despite major advances in the therapeutic armamentarium of MM, only 50% of patients survive more than 5 years after diagnosis, with significantly lower rates (21%) for high-risk patients. Chimeric Antigen Receptor (CAR) T-cell therapy targeting BCMA (B-cell maturation antigen) shows high response rates in relapsed/refractory patients. However, most patients have disease remission that lasts less than 18 months, prompting the search for additional and synergistic therapeutic approaches. We unbiasedly mapped the cell surface proteome of MM by integrating Mass-Spectrometry (MS) and RNA-seq analyses from 7 MM cell lines and 904 primary MM patient samples bearing high-risk cytogenetics. To identify cell surface proteins, we ran a pool of 4,761 proteins and 16,000+ transcripts through five repositories. An integrated scoring database was developed by scoring each ID based on the number of databases (0-5) it was identified in, with 0 if the molecule was not found in any and 5 if the protein was found in all five. We identified 402 proteins with a surface score of 3 or higher in MM cell lines and patient samples by transcriptomics and proteomics. We prioritized the 326 candidates that were more highly expressed in patients. Based on functional enrichment analyses, we found the proteins formed three main networks with immune mechanisms representing the largest cluster (227 out of 326 cell surface proteins) followed by transporters and adhesion proteins.Based on a pipeline we previously established (1), we further selected 97 candidates minimally expressed in normal tissues. This list included current therapeutic targets such as BCMA, SLAMF7, ITGB7 and LY9. Validation in primary patient samples by western blot and flow-cytometric analyses, enabled the identification of 10 top candidates (CCR1, CD320, FCRL3, IL12RB1, ITGA4, LAX1, LILRB4, LRRC8D, SEMA4A, SLAMF6) that resulted most frequently and highly expressed. We found that LAX1, LILRB4 and SEMA4A significantly impact myeloma patient overall survival based on Kaplan-Meier analysis in the MM Research Foundation (MMRF) cohort (2). CCR1, IL12RB1, LILRB4 and SEMA4A were upregulated by the treatment with Bortezomib or Venetoclax that conversely, decreased BCMA expression in MM U266 cells. By stratifying the patient population, we found that the SEMA4A and LAX1 were up-regulated in patients with t(4;14) compared to patients with no cytogenetic abnormality; LILRB4 in patients with t(14;16) and CCR1 patients with t(14;16) and t(14;20). By calculating co-expression levels CCR1-LILRB4 and CCR1-FCRL3 resulted co-expressed in 100% of patients. For safety purposes (3), we excluded candidates with high (&gt;55%) protein abundance in highly-purified normal hematopoietic stem cells and activated T-cells, narrowing down the list to 6 top candidates (CCR1, FCRL3, IL12RB1, LILRB4, LRRC8D, SEMA4A). To define the function of this group of promising cell surface targets, we used a CRISPR/Cas9 inducible system in KMS11 MM cells. We found that knock-out of CCR1, LRRC8D and SEMA4A individually reduces the MM cell growth by ~60%, 50% and 50% respectively, and almost completely abrogates MM cell migration through porous chambers by &gt;80%. By co-culturing irradiated KO and control MM cells with healthy donor T-cells we also found that lack of CCR1 increased T-cell proliferation by 50% compared to controls and enhanced killing of MM cells, suggesting that CCR1 may suppress T-cell mediated immune responses in addition to play a role in MM cell survival and migration. This study suggests the contribution of an altered MM surfaceome to disease development and may lead to potential novel immunotherapeutic approaches for high-risk MM. References 1. Perna F et al., Cancer Cell 2017 3. Dong C et al., in press Oncogene 2021 Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


1993 ◽  
Vol 121 (5) ◽  
pp. 1141-1152 ◽  
Author(s):  
E A Wayner ◽  
S G Gil ◽  
G F Murphy ◽  
M S Wilke ◽  
W G Carter

The cutaneous T cell lymphomas (CTCL), typified by mycosis fungoides, and several chronic T cell mediated dermatoses are characterized by the migration of T lymphocytes into the epidermis (epidermotropism). Alternatively, other types of cutaneous inflammation (malignant cutaneous B cell lymphoma, CBCL, or lymphocytoma cutis, non-malignant T or B cell type) do not show evidence of epidermotropism. This suggests that certain T lymphocyte subpopulations are able to interact with and penetrate the epidermal basement membrane. We show here that T lymphocytes derived from patients with CTCL (HUT 78 or HUT 102 cells), adhere to the detergent-insoluble extracellular matrix prepared from cultured basal keratinocytes (HFK ECM). HUT cell adhesion to HFK ECM was inhibitable with monoclonal antibodies (mAbs) directed to the alpha 3 (P1B5) or beta 1 (P4C10) integrin receptors, and could be up-regulated by an activating anti-beta 1 mAb (P4G11). An inhibitory mAb, P3H9-2, raised against keratinocytes identified epiligrin as the ligand for alpha 3 beta 1 positive T cells in HFK ECM. Interestingly, two lymphocyte populations could be clearly distinguished relative to expression of alpha 3 beta 1 by flow cytometry analysis. Lymphokine activated killer cells, alloreactive cytotoxic T cells and T cells derived from patients with CTCL expressed high levels of alpha 3 beta 1 (alpha 3 beta 1high). Non-adherent peripheral blood mononuclear cells, acute T or B lymphocytic leukemias, or non-cutaneous T or B lymphocyte cell lines expressed low levels of alpha 3 beta 1 (alpha 3 beta 1low). Resting PBL or alpha 3 beta 1low T or B cell lines did not adhere to HFK ECM or purified epiligrin. However, adhesion to epiligrin could be up-regulated by mAbs which activate the beta 1 subunit indicating that alpha 3 beta 1 activity is a function of expression and affinity. In skin derived from patients with graft-vs.-host (GVH) disease, experimentally induced delayed hypersensitivity reactions, and CTCL, the infiltrating T cells could be stained with mAbs to alpha 3 or beta 1 and were localized in close proximity to the epiligrin-containing basement membrane. Infiltrating lymphocytes in malignant cutaneous B disease (CBCL) did not express alpha 3 beta 1 by immunohistochemical techniques and did not associate with the epidermal basement membrane. The present findings clearly define a function for alpha 3 beta 1 in T cells and strongly suggest that alpha 3 beta 1 interaction with epiligrin may be involved in the pathogenesis of cutaneous inflammation.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 28-29
Author(s):  
Jie Wang ◽  
Katarzyna Urbanska ◽  
Prannda Sharma ◽  
Mathilde Poussin ◽  
Reza Nejati ◽  
...  

Background: Peripheral T-cell lymphomas (PTCL) encompass a highly heterogeneous group of T-cell malignancies and are generally associated with a poor prognosis. Combination chemotherapy results in consistently poorer outcomes for T-cell lymphomas compared with B-cell lymphomas.1 There is an urgent clinical need to develop novel approaches to treatment of PTCL. While CD19- and CD20-directed immunotherapies have been successful in the treatment of B-cell malignancies, T-cell malignancies lack suitable immunotherapeutic targets. Brentuximab Vedotin, a CD30 antibody-drug conjugate, is not applicable to PTCL subtypes which do not express CD30.2 Broadly targeting pan-T cell markers is predicted to result in extensive T-cell depletion and clinically significant immune deficiency; therefore, a more tumor-specific antigen that primarily targets the malignant T-cell clone is needed. We reasoned that since malignant T cells are clonal and express the same T-cell receptor (TCR) in a given patient, and since the TCR β chain in human α/β TCRs can be grouped into 24 functional Vβ families targetable by monoclonal antibodies, immunotherapeutic targeting of TCR Vβ families would be an attractive strategy for the treatment of T-cell malignancies. Methods: We developed a flexible approach for targeting TCR Vβ families by engineering T cells to express a CD64 chimeric immune receptor (CD64-CIR), comprising a CD3ζ T cell signaling endodomain, CD28 costimulatory domain, and the high-affinity Fc gamma receptor I, CD64. T cells expressing CD64-CIR are predicted to be directed to tumor cells by Vβ-specific monoclonal antibodies that target tumor cell TCR, leading to T cell activation and induction of tumor cell death by T cell-mediated cytotoxicity. Results: This concept was first evaluated in vitro using cell lines. SupT1 T-cell lymphoblasts, which do not express a native functioning TCR, were stably transduced to express a Vβ12+ MART-1 specific TCR, resulting in a Vβ12 TCR expressing target T cell line.3 Vβ family specific cytolysis was confirmed by chromium release assays using co-culture of CD64 CIR transduced T cells with the engineered SupT1-Vβ12 cell line in the presence of Vβ12 monoclonal antibody. Percent specific lysis was calculated as (experimental - spontaneous lysis / maximal - spontaneous lysis) x 100. Controls using no antibody, Vβ8 antibody, and untransduced T cells did not show significant cytolysis (figure A). Next, the Jurkat T cell leukemic cell line, which expresses a native Vβ8 TCR, was used as targets in co-culture. Again, Vβ family target specific cytolysis was achieved in the presence of CD64 CIR T cells and Vβ8, but not Vβ12 control antibody. Having demonstrated Vβ family specific cytolysis in vitro using target T cell lines, we next evaluated TCR Vβ family targeting in vivo. Immunodeficient mice were injected with SupT1-Vβ12 or Jurkat T cells with the appropriate targeting Vβ antibody, and either CD64 CIR T cells or control untransduced T cells. The cell lines were transfected with firefly luciferase and tumor growth was measured by bioluminescence. The CD64 CIR T cells, but not untransduced T cells, in conjunction with the appropriate Vβ antibody, successfully controlled tumor growth (figure B). Our results provide proof-of-concept that TCR Vβ family specific T cell-mediated cytolysis is feasible, and informs the development of novel immunotherapies that target TCR Vβ families in T-cell malignancies. Unlike approaches that target pan-T cell antigens, this approach is not expected to cause substantial immune deficiency and could lead to a significant advance in the treatment of T-cell malignancies including PTCL. References 1. Coiffier B, Brousse N, Peuchmaur M, et al. Peripheral T-cell lymphomas have a worse prognosis than B-cell lymphomas: a prospective study of 361 immunophenotyped patients treated with the LNH-84 regimen. The GELA (Groupe d'Etude des Lymphomes Agressives). Ann Oncol Off J Eur Soc Med Oncol. 1990;1(1):45-50. 2. Horwitz SM, Advani RH, Bartlett NL, et al. Objective responses in relapsed T-cell lymphomas with single agent brentuximab vedotin. Blood. 2014;123(20):3095-3100. 3. Hughes MS, Yu YYL, Dudley ME, et al. Transfer of a TCR Gene Derived from a Patient with a Marked Antitumor Response Conveys Highly Active T-Cell Effector Functions. Hum Gene Ther. 2005;16(4):457-472. Figure Disclosures Schuster: Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding; AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria.


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