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Introduction: TGFβ is a major immunoinhibitory factor present in the microenvironment of solid tumors. Various cancer types acquire the ability to overexpress TGFβ to escape immune response. Specifically, TGFβ dampens cytotoxic T cell activity, and its presence has been correlated with tumor invasion and poor prognosis. Methods: In this study, we developed two approaches to counteract the effects of TGFβ and provide a functional advantage to genetically engineered T cells in the immunoinhibitory tumor milieu. We designed a TGFβRI-based co-stimulatory switch receptor (CSRI), comprising the TGFβ receptor I extracellular binding domain and a 4-1BB co-stimulatory signaling moiety. Additionally, we tested the efficacy of a TGFβ-binding scFv trap produced by T cells. Results: We demonstrated that both approaches enhanced tumor-specific T cell cytokine secretion, upregulated activation markers, and reduced inhibition markers upon co-culture with melanoma targets. Furthermore, CSRI and the anti-TGFβ trap exhibited improved anti-tumor function in vivo. Conclusion: Overall, we show that targeting the TGFβ pathway can enhance cellular immunotherapy. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Methods Results Conclusion Chimeric antigen receptor T‐cell (CAR‐T) therapy has demonstrated remarkable efficacy in relapsed or refractory large B cell lymphoma, but real‐world evidence is needed to confirm safety and efficacy when facing the unique challenges of a wide geographical catchment area.We reviewed patients treated with commercially available CAR‐T at a medium‐sized single center in Canada (The Ottawa Hospital) between December 2020 and July 2022 (Canadian implementation started in 2020).Fifty‐one patients (59% male, median age 62) traveled a median distance of 655 km (range 3–3659) for treatment. Median time from apheresis to CAR‐T infusion was 36 days (range 26–81). With a median follow‐up of 383 days (95% CI: 333–480), median progression‐free survival (PFS) and overall survival (OS) were 257 days (95% CI: 92‐NE) and 422 days (95% CI: 106‐NE), respectively. The median PFS for out‐of‐province patients was 115 days (95% CI: 91‐NE) versus 280 days for in‐province patients (95% CI: 142‐NE), p = 0.12. Multivariate analysis demonstrated that distance from treatment center (p = 0.05) and refractory disease status (p = 0.003) were independently associated with shorter PFS. The time from the last disease progression to CAR‐T referral was longer for out‐of‐province patients, but there was no difference in the time of referral to CAR‐T consult, apheresis, or CAR‐T infusion between in‐province and out‐of‐province patients.Our results confirm that despite the complexity of CAR‐T therapy administration, Ottawa can effectively provide commercial CAR‐T therapy in a timely fashion for patients from across the country. [ABSTRACT FROM AUTHOR]

Background: Chimeric antigen receptor (CAR)-T therapy has emerged as a promising treatment for hematologic malignancies. However, cytopenia remains one of the most frequent and challenging adverse effects of this therapy. Methods: We conducted a retrospective analysis of 26 patients with relapsed/refractory aggressive B-cell lymphoma who received CAR-T therapy at our center. Subsequently, to investigate measures to address cytopenias following CAR-T therapy, we isolated and generated murine CAR-T cells and bone marrow-derived mesenchymal stem cells (MSCs), establishing a murine syngeneic CAR-T therapy model. We assessed the impact of MSC infusion on hematopoietic recovery post-CAR-T therapy by evaluating complete blood count, bone marrow hematopoietic stem cells and their subpopulations, bone marrow histomorphology, and hematopoiesis-related genes. Results: All patients experienced cytopenias to varying degrees, with complete lineage involvement in half of the patients. Grade ≥ 3 cytopenias were observed in 88.46% of the patients. CAR-T therapy was associated with a higher incidence of biphasic, late-onset, or prolonged cytopenias. Survival analysis indicated that neutropenia and lymphopenia tended to be associated with better prognosis, whereas thrombocytopenia tended to be related to poorer outcomes. Through animal experiments, we discovered that MSCs infusion boosted HSCs and their long-term subpopulations, enhancing hematopoietic recovery, particularly in the megakaryocyte lineage, and mitigating bone marrow damage. Importantly, both in vitro and in vivo experiments demonstrated that MSCs did not compromise the activity or antitumor efficacy of CAR-T cells. Conclusions: Our findings propose MSCs infusion as a promising strategy to address cytopenias, particularly thrombocytopenia, after CAR-T therapy. This approach could help overcome certain limitations of cellular immunotherapy by enhancing hematopoietic recovery without compromising the efficacy of CAR-T cells. Highlights: Cytopenia is a frequently observed adverse effect following CAR-T therapy, and it is often characterized by biphasic and prolonged patterns. MSCs play a critical role in promoting hematopoietic recovery and mitigating bone marrow damage in a murine model of CAR-T therapy The activity and antitumor efficacy of CAR-T cells were not impaired by MSCs. [ABSTRACT FROM AUTHOR]

Noam E Kopmar,1,2 Ryan D Cassaday1,2 1Division of Hematology and Oncology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA; 2Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA, USACorrespondence: Ryan D Cassaday, Clinical Research Division, Fred Hutchinson Cancer Center, 825 Eastlake Ave E, Mailstop LG-700, Seattle, WA, 98109-1023, USA, Tel +1-206-606-6744, Fax +1-206-606-1987, Twitter/X @RyanCassaday, Email cassaday@uw.eduAbstract: Autologous chimeric antigen receptor-modified T-cell therapy (CAR-T) has revolutionized treatment paradigms across multiple lymphoid malignancies, including relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). The introduction of the CD19-directed CAR-T product brexucabtagene autoleucel (brexu-cel; Tecartus) in October 2021 made this treatment approach available for the first time for adults with R/R B-ALL, a historically challenging clinical entity to treat. In this review, we will discuss the pivotal clinical trial data from the ZUMA-3 study that led to the US Food and Drug Administration (FDA) approval of brexu-cel, including clinical outcomes and key toxicity data (most importantly, the incidence and severity of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome). Additionally, we will compare and contrast these data from the ZUMA-3 study with “real-world” data from examinations of patient outcomes with brexu-cel as an FDA-approved therapy in R/R B-ALL, and discuss practical considerations with brexu-cel use in the clinic, including the role of consolidative allografting for patients post-brexu-cel. We finish by discussing future directions for CAR-T use in R/R B-ALL with the anticipated introduction of a new CD19-directed CAR-T product – obecabtagene autoleucel – in the near future.Keywords: brexucabtagene autoleucel, acute lymphoblastic leukemia, adults, chimeric antigen receptor, cellular immunotherapy

Abstract Background Chimeric antigen receptor (CAR)-T therapy has emerged as a promising treatment for hematologic malignancies. However, cytopenia remains one of the most frequent and challenging adverse effects of this therapy. Methods We conducted a retrospective analysis of 26 patients with relapsed/refractory aggressive B-cell lymphoma who received CAR-T therapy at our center. Subsequently, to investigate measures to address cytopenias following CAR-T therapy, we isolated and generated murine CAR-T cells and bone marrow-derived mesenchymal stem cells (MSCs), establishing a murine syngeneic CAR-T therapy model. We assessed the impact of MSC infusion on hematopoietic recovery post-CAR-T therapy by evaluating complete blood count, bone marrow hematopoietic stem cells and their subpopulations, bone marrow histomorphology, and hematopoiesis-related genes. Results All patients experienced cytopenias to varying degrees, with complete lineage involvement in half of the patients. Grade ≥ 3 cytopenias were observed in 88.46% of the patients. CAR-T therapy was associated with a higher incidence of biphasic, late-onset, or prolonged cytopenias. Survival analysis indicated that neutropenia and lymphopenia tended to be associated with better prognosis, whereas thrombocytopenia tended to be related to poorer outcomes. Through animal experiments, we discovered that MSCs infusion boosted HSCs and their long-term subpopulations, enhancing hematopoietic recovery, particularly in the megakaryocyte lineage, and mitigating bone marrow damage. Importantly, both in vitro and in vivo experiments demonstrated that MSCs did not compromise the activity or antitumor efficacy of CAR-T cells. Conclusions Our findings propose MSCs infusion as a promising strategy to address cytopenias, particularly thrombocytopenia, after CAR-T therapy. This approach could help overcome certain limitations of cellular immunotherapy by enhancing hematopoietic recovery without compromising the efficacy of CAR-T cells. Highlights 1 Cytopenia is a frequently observed adverse effect following CAR-T therapy, and it is often characterized by biphasic and prolonged patterns. 2 MSCs play a critical role in promoting hematopoietic recovery and mitigating bone marrow damage in a murine model of CAR-T therapy 3 The activity and antitumor efficacy of CAR-T cells were not impaired by MSCs. Graphical Abstract

Intraperitoneal cellular immunotherapy with CAR-redirected lymphocytes is an intriguing approach to target peritoneal carcinomatosis (PC) from ovarian cancer (OC), which is currently evaluated in clinical trials. PC displays a composite structure with floating tumor cells within ascites and solid-like masses invading the peritoneum. Therefore, a comprehensive experimental model is crucial to optimize CAR-cell therapies in such a peculiar environment. Here, we explored the activity of cytokine-induced killer lymphocytes (CIK), redirected by CAR against mesothelin (MSLN-CAR.CIK), within reductionistic 3D models resembling the structural complexity of both liquid and solid components of PC. MSLN-CAR.CIK effectively killed and were functionally efficient against OC targets. In a "floating-like" 3D context with floating OC spheroids, both tumor localization and killing by MSLN-CAR.CIK were significantly boosted by fluid flow. In a "solid-like" context, MSLN-CAR.CIK were recruited through the extracellular matrix on embedded tumor aggregates, with variable kinetics depending on the effector-target distance. Furthermore, MSLN-CAR.CIK penetrated the inner levels of OC spheroids exerting effective tumor killing. Our findings provide currently unknown therapeutically relevant information on intraperitoneal approaches with CAR.CIK, supporting further developments and improvements for clinical studies in the context of locoregional cell therapy approaches for patients with PC from OC. [ABSTRACT FROM AUTHOR]

Tumor immunotherapy occupies a pivotal position in the field of hematological malignancies. Chimeric antigen receptor (CAR) T-cell therapy has established a new therapeutic pattern for hematological immunotherapy and achieved satisfactory clinical results in the treatment of B-lineage hematological malignancies. However, CAR T-cell therapy has some limitations in the treatment of T-cell acute lymphoblastic leukemia because of the presence of CAR T-cell fratricide, tumor cell contamination, T-cell aplasia, and other clinically relevant problems. Therefore, the current major challenge is overcoming the existing bottlenecks to optimize CAR-T therapy and improve its efficacy against T-ALL while improving the prognosis of patients.

Abstract Background This study details a case of a patient with advanced lung adenocarcinoma harboring an exon 19 deletion in the EGFR gene. Method A 46-year-old female patient was diagnosed with stage IVb left lung adenocarcinoma, with multiple bone and lymph node metastases. Following the identification of tumor-specific antigen peptides, the patient received a combination treatment of immunotherapy (TSA-DC-CTL) and oral osimertinib. Peripheral blood circulating immune cells and circulating tumor cells (CTCs) were monitored before and after treatment. PET-CT and CT scans were used to assess the tumor response to treatment. Results A significant increase in total lymphocyte percentage and decrease in the number of CTCs in the patient was observed. Imaging studies showed a notable reduction in tumor metastases. Conclusion This report demonstrates the safety and efficacy of TSA-DC-CTL cell immunotherapy combined with osimertinib in the treatment of a patient with advanced lung adenocarcinoma with an EGFR exon 19 deletions. This study describes a promising new treatment option for patients with advanced lung cancer with EGFR mutations.

Abstract Objective To construct chimeric antigen receptor (CAR)-T cells targeting epithelial cell adhesion molecule (EpCAM) antigen (anti-EpCAM-CAR-T). Methods A third-generation CAR-T cell construct used a single-chain variable fragment derived from monoclonal antibody against human EpCAM. Peripheral blood mononuclear cells were extracted from volunteers. The proportion of cluster of differentiation 8 positive (CD8+) and CD4 + T cells was measured using flow cytometry. Western blot was used to detect the expression of EpCAM-CAR. The killing efficiency was detected using the MTT assay and transwell assay, and the secretion of killer cytokines tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) was detected using the ELISA. The inhibitory effect of EpCAM-CAR-T on colorectal cancer in vivo was detected using xenografts. Results It was found that T cells expanded greatly, and the proportion of CD3+, CD8 + and CD4 + T cells was more than 60%. Furthermore, EpCAM-CAR-T cells had a higher tumour inhibition rate in the EpCAM expression positive group than in the negative group (P

Background: This study details a case of a patient with advanced lung adenocarcinoma harboring an exon 19 deletion in the EGFR gene. Method: A 46-year-old female patient was diagnosed with stage IVb left lung adenocarcinoma, with multiple bone and lymph node metastases. Following the identification of tumor-specific antigen peptides, the patient received a combination treatment of immunotherapy (TSA-DC-CTL) and oral osimertinib. Peripheral blood circulating immune cells and circulating tumor cells (CTCs) were monitored before and after treatment. PET-CT and CT scans were used to assess the tumor response to treatment. Results: A significant increase in total lymphocyte percentage and decrease in the number of CTCs in the patient was observed. Imaging studies showed a notable reduction in tumor metastases. Conclusion: This report demonstrates the safety and efficacy of TSA-DC-CTL cell immunotherapy combined with osimertinib in the treatment of a patient with advanced lung adenocarcinoma with an EGFR exon 19 deletions. This study describes a promising new treatment option for patients with advanced lung cancer with EGFR mutations. [ABSTRACT FROM AUTHOR]

Objective: To construct chimeric antigen receptor (CAR)-T cells targeting epithelial cell adhesion molecule (EpCAM) antigen (anti-EpCAM-CAR-T). Methods: A third-generation CAR-T cell construct used a single-chain variable fragment derived from monoclonal antibody against human EpCAM. Peripheral blood mononuclear cells were extracted from volunteers. The proportion of cluster of differentiation 8 positive (CD8+) and CD4 + T cells was measured using flow cytometry. Western blot was used to detect the expression of EpCAM-CAR. The killing efficiency was detected using the MTT assay and transwell assay, and the secretion of killer cytokines tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) was detected using the ELISA. The inhibitory effect of EpCAM-CAR-T on colorectal cancer in vivo was detected using xenografts. Results: It was found that T cells expanded greatly, and the proportion of CD3+, CD8 + and CD4 + T cells was more than 60%. Furthermore, EpCAM-CAR-T cells had a higher tumour inhibition rate in the EpCAM expression positive group than in the negative group (P < 0.05). The secretion of killer cytokines TNF-α and IFN-γ in the EpCAM expression positive cell group was higher than that in the negative group (P < 0.05). In the experimental group treated with EpCAM-CAR-T cells, the survival rate of nude mice was higher (P < 0.05), and the tumour was smaller than that in the blank and control groups (P < 0.05). The secretion of serum killer cytokines TNF-α and IFN-γ in tumour-bearing nude mice in the experimental group treated with EpCAM-CAR-T cells was higher than that in the blank and control groups (P < 0.05). Conclusion: This study successfully constructed EpCAM-CAR cells and found that they can target and recognise EpCAM-positive tumour cells, secrete killer cytokines TNF-α and IFN-γ and better inhibit the growth and metastasis of colorectal cancer in vitro and in vivo than unmodified T cells. [ABSTRACT FROM AUTHOR]

Tumor immunotherapy occupies a pivotal position in the field of hematological malignancies. Chimeric antigen receptor (CAR) T-cell therapy has established a new therapeutic pattern for hematological immunotherapy and achieved satisfactory clinical results in the treatment of B-lineage hematological malignancies. However, CAR T-cell therapy has some limitations in the treatment of T-cell acute lymphoblastic leukemia because of the presence of CAR T-cell fratricide, tumor cell contamination, T-cell aplasia, and other clinically relevant problems. Therefore, the current major challenge is overcoming the existing bottlenecks to optimize CAR-T therapy and improve its efficacy against T-ALL while improving the prognosis of patients. [ABSTRACT FROM AUTHOR]

The MET receptor is one of the main drivers of 'invasive growth', a multifaceted biological response essential during embryonic development and tissue repair that is usurped by cancer cells to induce and sustain the malignant phenotype. MET stands out as one of the most important oncogenes activated in cancer and its inhibition has been explored since the initial era of cancer-targeted therapy. Different approaches have been developed to hamper MET signaling and/or reduce MET (over)expression as a hallmark of transformation. Considering the great interest gained by cancer immunotherapy, this review evaluates the opportunity of targeting MET within therapeutic approaches based on the exploitation of immune functions, either in those cases where MET impairment is crucial to induce an effective response (i.e., when MET is the driver of the malignancy), or when blocking MET represents a way for potentiating the treatment (i.e., when MET is an adjuvant of tumor fitness). [ABSTRACT FROM AUTHOR]

IntroductionTGFβ is a major immunoinhibitory factor present in the microenvironment of solid tumors. Various cancer types acquire the ability to overexpress TGFβ to escape immune response. Specifically, TGFβ dampens cytotoxic T cell activity, and its presence has been correlated with tumor invasion and poor prognosis.MethodsIn this study, we developed two approaches to counteract the effects of TGFβ and provide a functional advantage to genetically engineered T cells in the immunoinhibitory tumor milieu. We designed a TGFβRI-based co-stimulatory switch receptor (CSRI), comprising the TGFβ receptor I extracellular binding domain and a 4-1BB co-stimulatory signaling moiety. Additionally, we tested the efficacy of a TGFβ-binding scFv trap produced by T cells.ResultsWe demonstrated that both approaches enhanced tumor-specific T cell cytokine secretion, upregulated activation markers, and reduced inhibition markers upon co-culture with melanoma targets. Furthermore, CSRI and the anti-TGFβ trap exhibited improved anti-tumor function in vivo.ConclusionOverall, we show that targeting the TGFβ pathway can enhance cellular immunotherapy.

Uveal melanoma (UM) is a rare melanoma originating in the eye’s uvea, with 50% of patients experiencing metastasis predominantly in the liver. In contrast to cutaneous melanoma, there is only a limited effectiveness of combined immune checkpoint therapies, and half of patients with uveal melanoma metastases succumb to disease within 2 years. This study aimed to provide a path toward enhancing immunotherapy efficacy by identifying and functionally validating tumor-reactive T cells in liver metastases of patients with UM. We employed single-cell RNA-seq of biopsies and tumor-infiltrating lymphocytes (TILs) to identify potential tumor-reactive T cells. Patient-derived xenograft (PDX) models of UM metastases were created from patients, and tumor sphere cultures were generated from these models for co-culture with autologous or MART1-specific HLA-matched allogenic TILs. Activated T cells were subjected to TCR-seq, and the TCRs were matched to those found in single-cell sequencing data from biopsies, expanded TILs, and in livers or spleens of PDX models injected with TILs. Our findings revealed that tumor-reactive T cells resided not only among activated and exhausted subsets of T cells, but also in a subset of cytotoxic effector cells. In conclusion, combining single-cell sequencing and functional analysis provides valuable insights into which T cells in UM may be useful for cell therapy amplification and marker selection.

Current therapies for autoimmune diseases are immunosuppressant agents, which have many debilitating side effects. However, dendritic cells (DCs) can induce antigen-specific tolerance. Tolerance restoration mediated by ex vivo-generated DCs can be a therapeutic approach. Therefore, in this review, we summarize the conceptual framework for developing ex vivo-generated DC strategies for autoimmune diseases. First, we will discuss the role of DCs in developing immune tolerance as a foundation for developing dendritic cell-based immunotherapy for autoimmune diseases. Then, we also discuss relevant findings from pre-clinical and clinical studies of ex vivo-generated DCs for therapy of autoimmune diseases. Finally, we discuss problems and challenges in dendritic cell therapy in autoimmune diseases. Throughout the article, we discuss autoimmune diseases, emphasizing SLE.

Cellular immunotherapy has shown considerable potential for the treatment of primary liver cancer (PLC), particularly hepatocellular carcinoma (HCC), although it is in the early stages of development. This study used bibliometric methods to delineate the evolution of research on cellular immunotherapy for PLC. Data were sourced from the Web of Science Core Collection (WoSCC) on April 22, 2024. Using the “Bibliometrix” R package, we examined primary bibliometric features, collaboration frequency between countries, and article output of the journals. Furthermore, we employed VOSviewer for coauthorship analysis and visualization and CiteSpace to assess keyword co-occurrence, as well as to spotlight keywords and references with the strongest citation bursts. Our analysis encompassed 492 publications focused on PLC and cellular immunotherapy, and we pinpointed China, Japan, and the USA as the foremost contributing nations and identified “Cancer Immunology Immunotherapy” as the journal with the most contributions in this area. Sun Yat-sen University emerged as the institution with the most significant output, and Li Zonghai authored the greatest number of leading articles. Prominent keywords that displayed a notable citation burst in the later years included “chimeric antigen receptor,” “combination therapy”, “CAR-T cells,” “TCR-T cells,” and “liver transplantation.” This bibliometric study outlined a foundational knowledge framework, surveyed over three decades of research on cellular immunotherapy for PLC, and revealed the key players and trends, thereby offering a thorough understanding of the field, especially in relation to HCC.

Chimeric antigen receptor (CAR) T cell therapy has transformed cancer immunotherapy. However, significant challenges limit its application beyond B cell-driven malignancies, including limited clinical efficacy, high toxicity, and complex autologous cell product manufacturing. Despite efforts to improve CAR T cell therapy outcomes, there is a growing interest in utilizing alternative immune cells to develop CAR cells. These immune cells offer several advantages, such as major histocompatibility complex (MHC)-independent function, tumor microenvironment (TME) modulation, and increased tissue infiltration capabilities. Currently, CAR products from various T cell subtypes, innate immune cells, hematopoietic progenitor cells, and even exosomes are being explored. These CAR products often show enhanced antitumor efficacy, diminished toxicity, and superior tumor penetration. With these benefits in mind, numerous clinical trials are underway to access the potential of these innovative CAR cells. This review aims to thoroughly examine the advantages, challenges, and existing insights on these new CAR products in cancer treatment. [ABSTRACT FROM AUTHOR]

Anaplastic thyroid cancer (ATC) is the most aggressive type of thyroid cancer. While ATC is rare, its mortality is high. Standard treatments, such as surgery, radiotherapy, and chemotherapy, have demonstrated limited efficacy in managing ATC. However, the advent of immunotherapy has significantly improved the prognosis for patients with ATC. Immunotherapy effectively targets and eliminates tumor cells by using the power of the body's immune cells. The neoantigen is an atypical protein generated by somatic mutation, is exclusively observed in neoplastic cells, and is devoid of central tolerance. Neoantigens exhibit enhanced specificity towards tumor cells and display robust immunogenic properties. Currently, neoantigen therapy is primarily applied in immune checkpoint inhibitors and cellular immunotherapy, encompassing adoptive immunotherapy and tumor vaccines. This study discusses the mechanism, tumor microenvironment, clinical trials, adverse events, limitations and future directions associated with ATC immunotherapy. [ABSTRACT FROM AUTHOR]

【Objective】Currently cellular immunotherapy is a fast-growing and reliable means of treating cancer. This study aims to develop a new method of detecting the effects of cell therapy products.【Method】By constructing tumor cells expressing green fluorescent protein（GFP）, a method for evaluating the cytotoxicity of cell therapy products was constructed based on a real-time live-cell dynamic imaging system.【Result】The real-time live-cell dynamic imaging system was used to monitor K562-GFP cells, and there was a good linear relationship between the total fluorescence intensity and the number of cells. In co-culture with extremely low effector to target（E∶T）ratio, high accuracy was also achieved. The cytotoxicity of natural killer（NK）cells was accurately evaluated by calculating the half-maximum effector concentration （EC50）of NK cells for K562-GFP cells. Flow cytometry（FCM）was used to detect the correlation between apoptosis of K562-GFP cells and the quenching of cell fluorescent protein, which proved the feasibility of the detection method.【Conclusion】This method can be used to evaluate killing ability of immune cells of different types or production processes at a low cost, without requiring the use of dyes or antibodies. [ABSTRACT FROM AUTHOR]

Transcription of distinct loci of human endogenous retroviruses (HERVs) and in some cases, translation of these transcripts have been consistently observed in many types of cancer. It is still debated whether HERV activation serves as a trigger for carcinogenesis or rather occurs as a consequence of epigenetic alterations and other molecular sequelae that characterize cellular transformation. Here we review the known molecular and epigenetic mechanisms of HERV activation in cancer cells as well as its potential contribution to carcinogenesis. Further, we describe the use of HERV expression in cancer diagnostic and characterize the potential of HERVderived antigens to serve as novel targets for cancer immunotherapy. We believe this review, which summarizes both what is known as well as unknown in this rapidly developing field, will boost interest in research on the therapeutic potential of targeting HERV elements in tumors and the impact of HERV activation in oncogenesis. [ABSTRACT FROM AUTHOR]

Adoptive cellular immunotherapy as a new paradigm to treat cancers is exemplified by the FDA approval of six chimeric antigen receptor-T cell therapies targeting hematological malignancies in recent years. Conventional αβ T cells applied in these therapies have proven efficacy but are confined almost exclusively to autologous use. When infused into patients with mismatched human leukocyte antigen, αβ T cells recognize tissues of such patients as foreign and elicit devastating graft-versus-host disease. Therefore, one way to overcome this challenge is to use naturally allogeneic immune cell types, such as γδ T cells. γδ T cells occupy the interface between innate and adaptive immunity and possess the capacity to detect a wide variety of ligands on transformed host cells. In this article, we review the fundamental biology of γδ T cells, including their subtypes, expression of ligands, contrasting roles in and association with cancer prognosis or survival, as well as discuss the gaps in knowledge pertaining to this cell type which we currently endeavor to elucidate. In addition, we propose how to harness the unique properties of γδ T cells for cellular immunotherapy based on lessons gleaned from past clinical trials and provide an update on ongoing trials involving these cells. Lastly, we elaborate strategies that have been tested or can be explored to improve the anti-tumor activity and durability of γδ T cells in vivo. [ABSTRACT FROM AUTHOR]

T cell therapy strategies, from allogeneic stem cell transplantation toward genetically‐modified T cells infusion, develop powerful anti‐tumor effects but are often accompanied by side effects and their efficacy remains sometimes to be improved. It therefore appears important to provide a flexible and easily reversible gene expression regulation system to control T cells activity. We developed a gene expression regulation technology that exploits the physiological GCN2‐ATF4 pathway's ability to induce gene expression in T cells in response to one essential amino acid deficiency. We first demonstrated the functionality of NUTRIREG in human T cells by transient expression of reporter genes. We then validated that NUTRIREG can be used in human T cells to transiently express a therapeutic gene such as IL‐10. Overall, our results represent a solid basis for the promising use of NUTRIREG to regulate transgene expression in human T cells in a reversible way, and more generally for numerous preventive or curative therapeutic possibilities in cellular immunotherapy strategies. [ABSTRACT FROM AUTHOR]

Despite major advances in therapeutic platforms, most patients with multiple myeloma (MM) eventually relapse and succumb to the disease. Among the novel therapeutic options developed over the past decade, genetically engineered T cells have a great deal of potential. Cellular immunotherapies, including chimeric antigen receptor (CAR) T cells, are rapidly becoming an effective therapeutic modality for MM. Marrow-infiltrating lymphocytes (MILs) derived from the bone marrow of patients with MM are a novel source of T cells for adoptive T-cell therapy, which robustly and specifically target myeloma cells. In this review, we examine the recent innovations in cellular immunotherapies, including the use of dendritic cells, and cellular tools based on MILs, natural killer (NK) cells, and CAR T cells, which hold promise for improving the efficacy and/or reducing the toxicity of treatment in patients with MM.

The MET receptor is one of the main drivers of ‘invasive growth’, a multifaceted biological response essential during embryonic development and tissue repair that is usurped by cancer cells to induce and sustain the malignant phenotype. MET stands out as one of the most important oncogenes activated in cancer and its inhibition has been explored since the initial era of cancer-targeted therapy. Different approaches have been developed to hamper MET signaling and/or reduce MET (over)expression as a hallmark of transformation. Considering the great interest gained by cancer immunotherapy, this review evaluates the opportunity of targeting MET within therapeutic approaches based on the exploitation of immune functions, either in those cases where MET impairment is crucial to induce an effective response (i.e., when MET is the driver of the malignancy), or when blocking MET represents a way for potentiating the treatment (i.e., when MET is an adjuvant of tumor fitness).

Transcription of distinct loci of human endogenous retroviruses (HERVs) and in some cases, translation of these transcripts have been consistently observed in many types of cancer. It is still debated whether HERV activation serves as a trigger for carcinogenesis or rather occurs as a consequence of epigenetic alterations and other molecular sequelae that characterize cellular transformation. Here we review the known molecular and epigenetic mechanisms of HERV activation in cancer cells as well as its potential contribution to carcinogenesis. Further, we describe the use of HERV expression in cancer diagnostic and characterize the potential of HERV-derived antigens to serve as novel targets for cancer immunotherapy. We believe this review, which summarizes both what is known as well as unknown in this rapidly developing field, will boost interest in research on the therapeutic potential of targeting HERV elements in tumors and the impact of HERV activation in oncogenesis.

Immune cell-based cancer therapies, such as chimeric antigen receptor T (CAR-T)-cell immunotherapy, have demonstrated impressive potency against hematological tumors. However, the efficacy of CAR-T cells against solid tumors remains limited. Herein, we designed tumor-targeting molecule-sialidase conjugates that potently and selectively stripped different sialoglycans from a variety of cancer cells. Desialylation enhanced induced pluripotent stem cell-derived chimeric antigen receptor-macrophage (CAR-iMac) infiltration and activation. Furthermore, the combination of cancer cell desialylation and CAR-iMac adoptive cellular therapy exerted a dramatic therapeutic effect on solid tumors and significantly prolonged the survival of tumor-bearing mice; these effects were mainly dependent on blockade of the checkpoint composed of sialic acid-binding immunoglobulin-like lectin (Siglec)-5 and Siglec-10 on the macrophages, and knockout of the glycoimmune checkpoint receptors could construct a CAR-iMac cell with stronger anticancer activity. This strategy that reverts the immune escape state ("cold tumor") to a sensitive recognition state ("hot tumor") has great significance for enhancing the effect of cellular immunotherapy on solid tumors. Therefore, desialylation combined with CAR-iMac cellular immunotherapy is a promising approach to enhance treatment with cellular immunotherapy and expand the valid indications among solid tumors, which provides inspiration for the development of cellular immunotherapies with glycoimmune checkpoint inhibition for the treatment of human cancer. [ABSTRACT FROM AUTHOR]

Epstein‒Barr virus (EBV) is a human herpes virus that is saliva-transmissible and universally asymptomatic. It has been confirmed that more than 90% of the population is latently infected with EBV for life. EBV can cause a variety of related cancers, such as nasopharyngeal carcinoma, diffuse large B-cell lymphoma, and Burkitt lymphoma. Currently, many clinical studies have demonstrated that EBV-specific cytotoxic T lymphocytes and other cell therapies can be safely and effectively transfused to prevent and treat some diseases caused by EBV. This review will mainly focus on discussing EBV-specific cytotoxic T lymphocytes and will touch on therapeutic EBV vaccines and chimeric antigen receptor T-cell therapy briefly. [ABSTRACT FROM AUTHOR]

Activation of T cells requires a rapid surge in cellular protein synthesis. However, the role of translation initiation in the early induction of specific genes remains unclear. Here, we show human translation initiation factor eIF3 interacts with select immune system related mRNAs including those encoding the T cell receptor (TCR) subunits TCRA and TCRB. Binding of eIF3 to the TCRA and TCRB mRNA 3'-untranslated regions (3'-UTRs) depends on CD28 coreceptor signaling and regulates a burst in TCR translation required for robust T cell activation. Use of the TCRA or TCRB 3'-UTRs to control expression of an anti-CD19 chimeric antigen receptor (CAR) improves the ability of CAR-T cells to kill tumor cells in vitro. These results identify a new mechanism of eIF3-mediated translation control that can aid T cell engineering for immunotherapy applications.

The global increase in cancer incidence presents significant economic and societal challenges. While chimeric antigen receptor-modified T cell (CAR-T) therapy has demonstrated remarkable success in hematologic malignancies and has earned FDA approval, its translation to solid tumors encounters faces significant obstacles, primarily centered around identifying reliable tumor-associated antigens and navigating the complexities of the tumor microenvironment. Recent developments in single-cell RNA sequencing (scRNA-seq) have greatly enhanced our understanding of tumors by offering high-resolution, unbiased analysis of cellular heterogeneity and molecular patterns. These technologies have revolutionized our comprehension of tumor immunology and have led to notable progress in cancer immunotherapy. This mini-review explores the progress of chimeric antigen receptor (CAR) cell therapy in solid tumor treatment and the application of scRNA-seq at various stages following the administration of CAR cell products into the body. The advantages of scRNA-seq are poised to further advance the investigation of the biological characteristics of CAR cells in vivo, tumor immune evasion, the impact of different cellular components on clinical efficacy, the development of clinically relevant biomarkers, and the creation of new targeted drugs and combination therapy approaches. The integration of scRNA-seq with CAR therapy represents a promising avenue for future innovations in cancer immunotherapy. This synergy holds the potential to enhance the precision and efficacy of CAR cell therapies while expanding their applications to a broader range of malignancies.

The design of chimeric antigen receptors (CAR) significantly enhances the antitumor efficacy of T cells. Although some CAR-T products have been approved by FDA in treating hematological tumors, adoptive immune therapy still faces many difficulties and challenges in the treatment of solid tumors. In this study, we reported a new strategy to treat solid tumors using a natural killer-like T (NKT) cell line which showed strong cytotoxicity to lyse 15 cancer cell lines, safe to normal cells and had low or no Graft-versus-host activity. We thus named it as universal NKT (UNKT). In both direct and indirect 3D tumor-like organ model, UNKT showed efficient tumor-killing properties, indicating that it could penetrate the microenvironment of solid tumors. In mesothelin (MSLN)-positive tumor cells (SKOV-3 and MCF-7), MSLN targeting CAR modified-UNKT cells had enhanced killing potential against MSLN positive ovarian cancer compared with the wild type UNKT, as well as MSLN-CAR-T cells. Compared with CAR-T, Single-cell microarray 32-plex proteomics revealed CAR-UNKT cells express more effector cytokines, such as perforin and granzyme B, and less interleukin-6 after activation. Moreover, our CAR-UNKT cells featured in more multifunctionality than CAR-T cells. CAR-UNKT cells also demonstrated strong antitumor activity in mouse models of ovarian cancer, with the ability to migrate and infiltrate the tumor without inducing immune memory. The fast-in and -out, enhanced and prolonged tumor killing properties of CAR-UNKT suggested a novel cure option of cellular immunotherapy in the treatment of MSLN-positive solid tumors.

γδ T cells, with their properties of both the innate and acquired immune systems, are suitable candidates for cellular immunotherapy in cancer. Because of their non-major histocompatibility complex (MHC) binding T cell receptor, allogenic transfer is feasible without relevant graft versus host reactions. In recent years, much experience has been gained with ex vivo expansion and stimulation of γδ T cells using bisphosphonates and Interleukin 2. Unfortunately, many current stimulation protocols are based on the use of xenogenic materials and other potentially hazardous supplements, which conflicts with basic principles of Good Manufacturing Practice (GMP). Adherence to the concept and current guidelines of GMP is state of the art for production of Advanced Therapy Medicinal Products (ATMP) like cell therapeutics and a necessity for clinical use under a regulatory perspective. In this study, we developed a new stimulation protocol that induces a marked increase of γδ T cell counts and allows for an easier transition from research to clinical applications with minimized regulatory workload. It reliably leads to a cell product with a purity of more than 90% γδ T cells and improved in vitro anti-tumor activity compared to our previous standard procedure. Furthermore, by investigating correlations between properties of unstimulated γδ T cells and proliferation rate as well as degranulation ability of stimulated γδ T cells, we can draw conclusions about suitable donors. Finally, we examined if expansion can be improved by pulsing zoledronate and/or using Interleukin 15 with or without Interleukin 2. Significant improvements can be achieved with respect to intrinsic and antibody-dependent cell-mediated cytotoxicity. Our results demonstrate that the stimulation protocol presented here leads to an improved γδ T cell product for future clinical applications. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T cells have demonstrated remarkable efficacy against hematological malignancies; however, they have not experienced the same success against solid tumors such as glioblastoma (GBM). There is a growing need for high-throughput functional screening platforms to measure CAR T-cell potency against solid tumor cells. We used real-time, label-free cellular impedance sensing to evaluate the potency of anti-disialoganglioside (GD2) targeting CAR T-cell products against GD2+ patient-derived GBM stem cells over a period of 2 days and 7 days in vitro. We compared CAR T products using two different modes of gene transfer: retroviral transduction and virus-free CRISPR-editing. Endpoint flow cytometry, cytokine analysis and metabolomics data were acquired and integrated to create a predictive model of CAR T-cell potency. Results indicated faster cytolysis by virus-free CRISPR-edited CAR T cells compared with retrovirally transduced CAR T cells, accompanied by increased inflammatory cytokine release, CD8+ CAR T-cell presence in co-culture conditions and CAR T-cell infiltration into three-dimensional GBM spheroids. Computational modeling identified increased tumor necrosis factor α concentrations with decreased glutamine, lactate and formate as being most predictive of short-term (2 days) and long-term (7 days) CAR T cell potency against GBM stem cells. These studies establish impedance sensing as a high-throughput, label-free assay for preclinical potency testing of CAR T cells against solid tumors. [ABSTRACT FROM AUTHOR]

Ring finger protein 43 (RNF43), a transmembrane E3 ubiquitin ligase, has been indicated to be a potential biomarker for gastric cancer treatment, as this protein increases tumour cell apoptosis and suppresses cellular proliferation. The role of RNF43 in cellular immunotherapy remains unclear. Herein, we aimed to explore the expression level of RNF43 in gastric cancer cell lines and its role in cellular immunotherapy. The expression level of RNF43 and PD‐L1 and their correlation in gastric cancer cell lines were analysed. The expression of PD‐L1 was negatively correlated with that of RNF43 in gastric cancer cell lines. RNF43 interacted with PD‐L1 to augment both K48‐ and K63‐linked ubiquitination of PD‐L1 in gastric cancer cell lines. In addition, RNF43 expression in gastric cancer cell lines could enhance the antitumour activity of T cells. In conclusion, this study reveals that RNF43 can inhibit PD‐L1 expression to enhance the antitumour activity of cellular immunotherapy. [ABSTRACT FROM AUTHOR]

Treatment and resolution of primary and metastatic brain tumors have long presented a challenge to oncologists. In response to the dismal survival outcomes associated with conventional therapies, various immunotherapy modalities, such as checkpoint inhibitors, vaccine, cellular immunotherapy and viral immunotherapy have been actively explored over the past couple of decades. Although improved patient survival has been more frequently noted in treatment of brain metastases, little progress has been made in improving patient survival in cases of primary brain tumors, specifically glioblastoma, which is the representative primary brain tumor discussed in this review. Herein, we will first overview the findings of recent clinical studies for treatment of primary and metastatic brain tumors with immunotherapeutic interventions. The clinical efficacy of these immunotherapies will be discussed in the context of their ability or inability to overcome inherent characteristics of the tumor as well as restricted antigen presentation and its immunosuppressive microenvironment. Additionally, this review aims to briefly inform clinicians in the field of neuro-oncology on the relevant aspects of the immune system as it pertains to the central nervous system, with special focus on the differing modes of antigen presentation and tumor microenvironment of primary and metastatic brain tumors and the role these differences may play in the efficacy of immunotherapy in eradicating the tumor.

Abstract In the last decade, Chimeric Antigen Receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach to fight cancers. This approach consists of genetically engineered immune cells expressing a surface receptor, called CAR, that specifically targets antigens expressed on the surface of tumor cells. In hematological malignancies like leukemias, myeloma, and non-Hodgkin B-cell lymphomas, adoptive CAR-T cell therapy has shown efficacy in treating chemotherapy refractory patients. However, the value of this therapy remains inconclusive in the context of solid tumors and is restrained by several obstacles including limited tumor trafficking and infiltration, the presence of an immunosuppressive tumor microenvironment, as well as adverse events associated with such therapy. Recently, CAR-Natural Killer (CAR-NK) and CAR-macrophages (CAR-M) were introduced as a complement/alternative to CAR-T cell therapy for solid tumors. CAR-NK cells could be a favorable substitute for CAR-T cells since they do not require HLA compatibility and have limited toxicity. Additionally, CAR-NK cells might be generated in large scale from several sources which would suggest them as promising off-the-shelf product. CAR-M immunotherapy with its capabilities of phagocytosis, tumor-antigen presentation, and broad tumor infiltration, is currently being investigated. Here, we discuss the emerging role of CAR-T, CAR-NK, and CAR-M cells in solid tumors. We also highlight the advantages and drawbacks of CAR-NK and CAR-M cells compared to CAR-T cells. Finally, we suggest prospective solutions such as potential combination therapies to enhance the efficacy of CAR-cells immunotherapy.

Abstract Background T cell receptor (TCR)-T cells possess similar effector function, but milder and more durable signal activation compared with chimeric antigen receptor-T cells. TCR-T cell therapy is another active field of cellular immunotherapy for cancer. Methods We previously developed a human anti-CD19 antibody (ET190L1) and generated novel CD19-specific γ/δ TCR-T cells, ET019003, by fusing the Fab fragment of ET190L1 with γ/δ TCR constant chain plus adding an ET190L1-scFv/CD28 co-stimulatory molecule. ET019003 cells were tested in preclinical studies followed by a phase 1 clinical trial. Results ET019003 cells produced less cytokines but retained comparable antitumor potency than ET190L1-CAR-T cells in vivo and in vitro. In the first-in-human trial, eight patients with relapsed or refractory DLBCL were treated. CRS of grade 1 was observed in three (37.5%) patients; ICANS of grade 3 was noted in one (12.5%) patient. Elevation of serum cytokines after ET019003 infusion was almost modest. With a median follow-up of 34 (range 6–38) months, seven (87.5%) patients attained clinical responses and six (75%) achieved complete responses (CR). OS, PFS and DOR at 3 years were 75.0%, 62.5%, and 71.4%, respectively. Notably, patient 1 with primary CNS lymphoma did not experience CRS or ICANS and got an ongoing CR for over 3 years after infusion, with detectable ET019003 cells in CSF. ET019003 showed striking in vivo expansion and persisted in 50% of patients at 12 months. Three patients received a second infusion, one for consolidation therapy after CR and two for salvage therapy after disease progression, but no response was observed. ET019003 expansion was striking in the first infusion, but poor in the second infusion. Conclusions CD19-specific γ/δ TCR-T cells, ET019003, had a good safety profile and could induce rapid responses and durable CR in patients with relapsed or refractory DLBCL, even primary CNS lymphoma, presenting a novel and potent therapeutic option for these patients. Trial registration: NCT04014894.

Chimeric antigen receptor (CAR) T cell therapy is a clinically approved cancer immunotherapy approach using genetically engineered T cells. The success of CAR T cells has been met with challenges regarding efficacy and safety. Although a broad spectrum of CAR T cell variants and applications is emerging, this review focuses on CAR T cells for the treatment of cancer. In the first part, the general principles of adoptive cell transfer, the architecture of the CAR molecule, and the effects of design on function are presented. The second part describes five conceptual challenges that hinder the success of CAR T cells; immunosuppressive tumour microenvironment, T cell intrinsic properties, tumour targeting, manufacturing cellular product, and immune-related adverse events. Throughout the review, selected current approaches to address these issues are presented.

Abstract Chimeric antigen receptor (CAR)-engineered T (CAR-T) cells have obtained prominent achievement in the clinical immunotherapy of hematological malignant tumors, leading to a rapid development of cellular immunotherapy in cancer treatment. Scientists are also aware of the prospective advantages of CAR engineering in cellular immunotherapy. Due to various limitations such as the serious side effects of CAR-T therapy, researchers began to investigate other immune cells for CAR modification. Natural killer (NK) cells are critical innate immune cells with the characteristic of non-specifically recognizing target cells and with the potential to become “off-the-shelf” products. In recent years, many preclinical studies on CAR-engineered NK (CAR-NK) cells have shown their remarkable efficacy in cancer therapy and their superiority over autologous CAR-T cells. In this review, we summarize the generation, mechanisms of anti-tumor activity and unique advantages of CAR-NK cells, and then analyze some challenges and recent clinical trials about CAR-NK cells therapy. We believe that CAR-NK therapy is a promising prospect for cancer immunotherapy in the future.

Abstract Cellular immunotherapy, including the chimeric antigen receptor T (CAR-T) cell therapy and CAR- natural killer (CAR-NK) cell therapy, has undergone extensive clinical investigation and development in recent years. CAR-T cell therapy is now emerging as a powerful cancer therapy with enormous potential, demonstrating impressive anti-tumor activity in the treatment of hematological malignancies. At the 2021 ASH annual meeting, numerous breakthroughs were reported concerning acute lymphocytic leukemia (ALL), lymphoma, acute myeloid leukemia (AML), and multiple myeloma (MM). Universal CAR-T cell and CAR-NK cell therapy, as well as induced pluripotent stem cell (iPSC)-derived immunotherapy, offer great “off-the-shelf” benefits. Major development and updates of cellular immunotherapy for hematological malignancies reported at the 2021 ASH annual meeting are summarized in this review.

CD19 chimeric antigen receptor (CAR) engineered NK cells have been used for treating patients with relapsed and/or refractory B cell malignancies and show encouraging outcomes and safety profile. However, the poor persistence of NK cells remains a major challenge for CAR NK cell therapy. Memory-like NK cells (MLNK) induced by IL-12, IL-15, and IL-18 have shown enhanced and prolonged responses to tumor re-stimulation, making them an attractive candidate for adoptive cellular immunotherapy. Here, we show efficient and stable gene delivery of CD19 CAR to memory-like NK cells using retroviral vectors with transduction efficiency comparable to those achieved with conventional NK cells. Analysis of surface molecules revealed a distinct phenotypic profile in CAR engineered memory-like NK cells (CAR MLNK), as evidenced by increased expression of CD94 and downregulation of NKp30 as well as KIR2DL1. Compared to conventional CAR NK cells, CAR MLNK cells exhibited significantly increased IFN-g production and degranulation in response to CD19+ target cells, resulting in enhanced cytotoxic activity against CD19+ leukemia cells and lymphoma cells. Furthermore, memory properties induced by IL-12/-15/-18 improved the in vivo persistence of CAR MLNK cells and significantly suppressed tumor growth in a exnograft mouse model of lymphoma, leading to prolonged survival of CD19+ tumor-bearing mouse. Altogether, our data indicate that CD19 CAR engineered memory-like NK cells exhibited superior persistence and antitumor activity against CD19+ tumors, which might be an attractive approach for treating patient with relapse or refractory B cell malignancies. [ABSTRACT FROM AUTHOR]

The widespread adoption of chimeric antigen receptor (CAR)-T cell therapy has been hindered by its complex and costly manufacturing process. Induced pluripotent stem cells (iPSCs) have shown promise as a cellular immunotherapy alternative, due to their unlimited self-renewal potential in culture and capacity to differentiate into functional immune cell types. However, it is imperative to carefully select the original cell for iPSC seed preparation, as iPSCs have been found to retain the epigenetic imprint of the original somatic cells. Additionally, the efficiency of reprogramming terminal differentiated cells for immunotherapy must be addressed. Our research highlights the superiority of lymphocyte-origin cells over embryonic stem cells in functional immune cell differentiation. Furthermore, blocking Fas-FasL induced apoptosis in T cells significantly improves iPSC generation. Interestingly, transient Fas suppression in T cells does not alter the expression of Fas in the resulting iPSCs or affect their differentiation potential. This finding brings up new avenues in the field of cellular immunotherapy and provides a solution for creating high-quality and suitable iPSCs for lymphocyte differentiation for immunotherapy purposes. • Our research has revealed that cells of lymphocyte origin outperformed embryonic stem cells for NK cell differentiation. • We clarify the importance of Fas/FasL for cell survival during terminally differentiated T cell reprogramming. • Transient Fas suppression provides a novel method for efficient induction of iPS from terminally differentiated T cells. • Transient reduction of Fas expression does not affect the pluripotency and differentiation potential of iPS. [ABSTRACT FROM AUTHOR]

The clinical use of cellular immunotherapies is gaining momentum and the number of approved indications is steadily increasing. One class of cellular therapies—chimeric antigen receptor (CAR)-modified T cells—has achieved impressive results in distinct blood cancer indications. These existing cellular therapies treating blood cancers face significant relapse rates, and their application beyond hematology has been underwhelming, especially in solid oncology. Major reasons for resistance source largely in the tumor microenvironment (TME). The TME in fact functionally suppresses, restricts, and excludes adoptive immune cells, which limits the efficacy of cellular immunotherapies from the onset. Many promising efforts are ongoing to adapt cellular immunotherapies to address these obstacles, with the aim of reshaping the tumor microenvironment to ameliorate function and to achieve superior efficacy against both hematological and solid malignancies. [ABSTRACT FROM AUTHOR]

γδ T cells, with their properties of both the innate and acquired immune systems, are suitable candidates for cellular immunotherapy in cancer. Because of their non-major histocompatibility complex (MHC) binding T cell receptor, allogenic transfer is feasible without relevant graft versus host reactions. In recent years, much experience has been gained with ex vivo expansion and stimulation of γδ T cells using bisphosphonates and Interleukin 2. Unfortunately, many current stimulation protocols are based on the use of xenogenic materials and other potentially hazardous supplements, which conflicts with basic principles of Good Manufacturing Practice (GMP). Adherence to the concept and current guidelines of GMP is state of the art for production of Advanced Therapy Medicinal Products (ATMP) like cell therapeutics and a necessity for clinical use under a regulatory perspective. In this study, we developed a new stimulation protocol that induces a marked increase of γδ T cell counts and allows for an easier transition from research to clinical applications with minimized regulatory workload. It reliably leads to a cell product with a purity of more than 90% γδ T cells and improved in vitro anti-tumor activity compared to our previous standard procedure. Furthermore, by investigating correlations between properties of unstimulated γδ T cells and proliferation rate as well as degranulation ability of stimulated γδ T cells, we can draw conclusions about suitable donors. Finally, we examined if expansion can be improved by pulsing zoledronate and/or using Interleukin 15 with or without Interleukin 2. Significant improvements can be achieved with respect to intrinsic and antibody-dependent cell-mediated cytotoxicity. Our results demonstrate that the stimulation protocol presented here leads to an improved γδ T cell product for future clinical applications.