Showing papers on "Antigen published in 2015"
TL;DR: CD19-CAR T cell therapy is feasible, safe, and mediates potent anti-leukaemic activity in children and young adults with chemotherapy-resistant B-precursor acute lymphoblastic leukaemia and non-Hodgkin lymphoma.
2,394 citations
TL;DR: Investigating the roles of tumor-specific neoantigens and alterations in the tumor microenvironment in the response to ipilimumab found no recurrent neoantigen peptide sequences predicted responder patient populations, suggesting detailed integrated molecular characterization of large patient cohorts may be needed to identify robust determinants of response and resistance to immune checkpoint inhibitors.
Abstract: Monoclonal antibodies directed against cytotoxic T lymphocyte–associated antigen-4 (CTLA-4), such as ipilimumab, yield considerable clinical benefit for patients with metastatic melanoma by inhibiting immune checkpoint activity, but clinical predictors of response to these therapies remain incompletely characterized. To investigate the roles of tumor-specific neoantigens and alterations in the tumor microenvironment in the response to ipilimumab, we analyzed whole exomes from pretreatment melanoma tumor biopsies and matching germline tissue samples from 110 patients. For 40 of these patients, we also obtained and analyzed transcriptome data from the pretreatment tumor samples. Overall mutational load, neoantigen load, and expression of cytolytic markers in the immune microenvironment were significantly associated with clinical benefit. However, no recurrent neoantigen peptide sequences predicted responder patient populations. Thus, detailed integrated molecular characterization of large patient cohorts may be needed to identify robust determinants of response and resistance to immune checkpoint inhibitors.
2,065 citations
TL;DR: It is shown that tumor-imposed metabolic restrictions can mediate T cell hyporesponsiveness during cancer, and it is found that blocking PD-L1 directly on tumors dampens glycolysis by inhibiting mTOR activity and decreasing expression of gly colysis enzymes.
1,983 citations
TL;DR: Major tumour regressions are reported in a subset of patients with metastatic melanoma treated with an anti-CTLA4 antibody and radiation and reproduced this effect in mouse models, showing that PD-L1 on melanoma cells allows tumours to escape anti- NCTLA4-based therapy, and the combination of radiation, anti- CTLA4 and anti-PD-L 1 promotes response and immunity through distinct mechanisms.
Abstract: Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies. This raises fundamental questions about mechanisms of non-redundancy and resistance. Here we report major tumour regressions in a subset of patients with metastatic melanoma treated with an anti-CTLA4 antibody (anti-CTLA4) and radiation, and reproduced this effect in mouse models. Although combined treatment improved responses in irradiated and unirradiated tumours, resistance was common. Unbiased analyses of mice revealed that resistance was due to upregulation of PD-L1 on melanoma cells and associated with T-cell exhaustion. Accordingly, optimal response in melanoma and other cancer types requires radiation, anti-CTLA4 and anti-PD-L1/PD-1. Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio. Radiation enhances the diversity of the T-cell receptor (TCR) repertoire of intratumoral T cells. Together, anti-CTLA4 promotes expansion of T cells, while radiation shapes the TCR repertoire of the expanded peripheral clones. Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion. Similarly to results from mice, patients on our clinical trial with melanoma showing high PD-L1 did not respond to radiation plus anti-CTLA4, demonstrated persistent T-cell exhaustion, and rapidly progressed. Thus, PD-L1 on melanoma cells allows tumours to escape anti-CTLA4-based therapy, and the combination of radiation, anti-CTLA4 and anti-PD-L1 promotes response and immunity through distinct mechanisms.
1,872 citations
TL;DR: The in vivo expansion of theCAR T cells correlated with clinical responses, and the CAR T cells persisted and remained functional beyond 4 years in the first two patients achieving CR, suggesting that disease eradication may be possible in some patients with advanced CLL.
Abstract: Patients with multiply relapsed or refractory chronic lymphocytic leukemia (CLL) have a poor prognosis. Chimeric antigen receptor (CAR)-modified T cells targeting CD19 have the potential to improve on the low complete response rates with conventional therapies by inducing sustained remissions in patients with refractory B cell malignancies. We previously reported preliminary results on three patients with refractory CLL. We report the mature results from our initial trial using CAR-modified T cells to treat 14 patients with relapsed and refractory CLL. Autologous T cells transduced with a CD19-directed CAR (CTL019) lentiviral vector were infused into patients with relapsed/refractory CLL at doses of 0.14 × 10(8) to 11 × 10(8) CTL019 cells (median, 1.6 × 10(8) cells). Patients were monitored for toxicity, response, expansion, and persistence of circulating CTL019 T cells. The overall response rate in these heavily pretreated CLL patients was 8 of 14 (57%), with 4 complete remissions (CR) and 4 partial remissions (PR). The in vivo expansion of the CAR T cells correlated with clinical responses, and the CAR T cells persisted and remained functional beyond 4 years in the first two patients achieving CR. No patient in CR has relapsed. All responding patients developed B cell aplasia and experienced cytokine release syndrome, coincident with T cell proliferation. Minimal residual disease was not detectable in patients who achieved CR, suggesting that disease eradication may be possible in some patients with advanced CLL.
1,373 citations
TL;DR: The results demonstrate the feasibility and effectiveness of treating chemotherapy-refractory B-cell malignancies with anti-CD19 CAR T cells and provide strong support for further development of this approach.
Abstract: Purpose T cells can be genetically modified to express an anti-CD19 chimeric antigen receptor (CAR). We assessed the safety and efficacy of administering autologous anti-CD19 CAR T cells to patients with advanced CD19 B-cell malignancies. Patients and Methods We treated 15 patients with advanced B-cell malignancies. Nine patients had diffuse large B-cell lymphoma (DLBCL), two had indolent lymphomas, and four had chronic lymphocytic leukemia. Patients received a conditioning chemotherapy regimen of cyclophosphamide and fludarabine followed by a single infusion of anti-CD19 CAR T cells. Results Of 15 patients, eight achieved complete remissions (CRs), four achieved partial remissions, one had stable lymphoma, and two were not evaluable for response. CRs were obtained by four of seven evaluable patients with chemotherapy-refractory DLBCL; three of these four CRs are ongoing, with durations ranging from 9 to 22 months. Acute toxicities including fever, hypotension, delirium, and other neurologic toxicities occurred in some patients after infusion of anti-CD19 CAR T cells; these toxicities resolved within 3 weeks after cell infusion. One patient died suddenly as a result of an unknown cause 16 days after cell infusion. CAR T cells were detected in the blood of patients at peak levels, ranging from nine to 777 CAR-positive T cells/L.
1,354 citations
TL;DR: The tailored immunotherapy approach introduced here may be regarded as a universally applicable blueprint for comprehensive exploitation of the substantial neo-epitope target repertoire of cancers, enabling the effective targeting of every patient’s tumour with vaccines produced ‘just in time’.
Abstract: Tumour-specific mutations are ideal targets for cancer immunotherapy as they lack expression in healthy tissues and can potentially be recognized as neo-antigens by the mature T-cell repertoire. Their systematic targeting by vaccine approaches, however, has been hampered by the fact that every patient's tumour possesses a unique set of mutations ('the mutanome') that must first be identified. Recently, we proposed a personalized immunotherapy approach to target the full spectrum of a patient's individual tumour-specific mutations. Here we show in three independent murine tumour models that a considerable fraction of non-synonymous cancer mutations is immunogenic and that, unexpectedly, the majority of the immunogenic mutanome is recognized by CD4(+) T cells. Vaccination with such CD4(+) immunogenic mutations confers strong antitumour activity. Encouraged by these findings, we established a process by which mutations identified by exome sequencing could be selected as vaccine targets solely through bioinformatic prioritization on the basis of their expression levels and major histocompatibility complex (MHC) class II-binding capacity for rapid production as synthetic poly-neo-epitope messenger RNA vaccines. We show that vaccination with such polytope mRNA vaccines induces potent tumour control and complete rejection of established aggressively growing tumours in mice. Moreover, we demonstrate that CD4(+) T cell neo-epitope vaccination reshapes the tumour microenvironment and induces cytotoxic T lymphocyte responses against an independent immunodominant antigen in mice, indicating orchestration of antigen spread. Finally, we demonstrate an abundance of mutations predicted to bind to MHC class II in human cancers as well by employing the same predictive algorithm on corresponding human cancer types. Thus, the tailored immunotherapy approach introduced here may be regarded as a universally applicable blueprint for comprehensive exploitation of the substantial neo-epitope target repertoire of cancers, enabling the effective targeting of every patient's tumour with vaccines produced 'just in time'.
963 citations
TL;DR: This first evaluation of the safety and efficacy of HER2-CAR T cells in patients with cancer shows the cells can persist for 6 weeks without evident toxicities, setting the stage for studies that combine Her2- CAR T cells with other immunomodulatory approaches to enhance their expansion and persistence.
Abstract: Purpose The outcome for patients with metastatic or recurrent sarcoma remains poor. Adoptive therapy with tumor-directed T cells is an attractive therapeutic option but has never been evaluated in sarcoma. Patients and Methods We conducted a phase I/II clinical study in which patients with recurrent/refractory human epidermal growth factor receptor 2 (HER2) –positive sarcoma received escalating doses (1 × 104/m2 to 1 × 108/m2) of T cells expressing an HER2-specific chimeric antigen receptor with a CD28.ζ signaling domain (HER2-CAR T cells). Results We enrolled 19 patients with HER2-positive tumors (16 osteosarcomas, one Ewing sarcoma, one primitive neuroectodermal tumor, and one desmoplastic small round cell tumor). HER2-CAR T-cell infusions were well tolerated with no dose-limiting toxicity. At dose level 3 (1 × 105/m2) and above, we detected HER2-CAR T cells 3 hours after infusion by quantitative polymerase chain reaction in 14 of 16 patients. HER2-CAR T cells persisted for at least 6 weeks in seven of ...
751 citations
TL;DR: NY-ESO-1–LAGE-1 TCR–engineered T cells were safe, trafficked to marrow and showed extended persistence that correlated with clinical activity against antigen-positive myeloma, according to the expected mechanism of action of the transferred T cells.
Abstract: Despite recent therapeutic advances, multiple myeloma (MM) remains largely incurable. Here we report results of a phase I/II trial to evaluate the safety and activity of autologous T cells engineered to express an affinity-enhanced T cell receptor (TCR) recognizing a naturally processed peptide shared by the cancer-testis antigens NY-ESO-1 and LAGE-1. Twenty patients with antigen-positive MM received an average 2.4 × 10(9) engineered T cells 2 d after autologous stem cell transplant. Infusions were well tolerated without clinically apparent cytokine-release syndrome, despite high IL-6 levels. Engineered T cells expanded, persisted, trafficked to marrow and exhibited a cytotoxic phenotype. Persistence of engineered T cells in blood was inversely associated with NY-ESO-1 levels in the marrow. Disease progression was associated with loss of T cell persistence or antigen escape, in accordance with the expected mechanism of action of the transferred T cells. Encouraging clinical responses were observed in 16 of 20 patients (80%) with advanced disease, with a median progression-free survival of 19.1 months. NY-ESO-1-LAGE-1 TCR-engineered T cells were safe, trafficked to marrow and showed extended persistence that correlated with clinical activity against antigen-positive myeloma.
699 citations
TL;DR: The current knowledge of the mechanisms of uptake and processing of antigens, the intracellular formation of peptide–MHC class II complexes, the intrusion into the plasma membrane of the APC plasma membrane and their ultimate degradation are described.
Abstract: Antigenic peptide-loaded MHC class II molecules (peptide-MHC class II) are constitutively expressed on the surface of professional antigen-presenting cells (APCs), including dendritic cells, B cells, macrophages and thymic epithelial cells, and are presented to antigen-specific CD4(+) T cells. The mechanisms of antigen uptake, the nature of the antigen processing compartments and the lifetime of cell surface peptide-MHC class II complexes can vary depending on the type of APC. It is likely that these differences are important for the function of each distinct APC subset in the generation of effective adaptive immune responses. In this Review, we describe our current knowledge of the mechanisms of uptake and processing of antigens, the intracellular formation of peptide-MHC class II complexes, the intracellular trafficking of peptide-MHC class II complexes to the APC plasma membrane and their ultimate degradation.
693 citations
TL;DR: The results suggest that, during infectious lung injury, Treg cells have a major direct and non-redundant role in tissue repair and maintenance-distinct from their role in suppression of immune responses and inflammation-and that these two essential Treg cell functions are invoked by separable cues.
TL;DR: The clinical benefit of therapeutic cancer vaccines has been established and the specificity of therapeutic vaccination combined with such immunomodulation offers an attractive avenue for the development of future cancer therapies.
Abstract: The clinical benefit of therapeutic cancer vaccines has been established. Whereas regression of lesions was shown for premalignant lesions caused by HPV, clinical benefit in cancer patients was mostly noted as prolonged survival. Suboptimal vaccine design and an immunosuppressive cancer microenvironment are the root causes of the lack of cancer eradication. Effective cancer vaccines deliver concentrated antigen to both HLA class I and II molecules of DCs, promoting both CD4 and CD8 T cell responses. Optimal vaccine platforms include DNA and RNA vaccines and synthetic long peptides. Antigens of choice include mutant sequences, selected cancer testis antigens, and viral antigens. Drugs or physical treatments can mitigate the immunosuppressive cancer microenvironment and include chemotherapeutics, radiation, indoleamine 2,3-dioxygenase (IDO) inhibitors, inhibitors of T cell checkpoints, agonists of selected TNF receptor family members, and inhibitors of undesirable cytokines. The specificity of therapeutic vaccination combined with such immunomodulation offers an attractive avenue for the development of future cancer therapies.
TL;DR: It is demonstrated that tumor-infiltrating lymphocytes (TILs) from 9 out of 10 patients with metastatic gastrointestinal cancers contained CD4+ and/or CD8+ T cells that recognized one to three neo-epitopes derived from somatic mutations expressed by the patient’s own tumor.
Abstract: It is unknown whether the human immune system frequently mounts a T cell response against mutations expressed by common epithelial cancers. Using a next-generation sequencing approach combined with high-throughput immunologic screening, we demonstrated that tumor-infiltrating lymphocytes (TILs) from 9 out of 10 patients with metastatic gastrointestinal cancers contained CD4(+) and/or CD8(+) T cells that recognized one to three neo-epitopes derived from somatic mutations expressed by the patient's own tumor. There were no immunogenic epitopes shared between these patients. However, we identified in one patient a human leukocyte antigen-C*08:02-restricted T cell receptor from CD8(+) TILs that targeted the KRAS(G12D) hotspot driver mutation found in many human cancers. Thus, a high frequency of patients with common gastrointestinal cancers harbor immunogenic mutations that can potentially be exploited for the development of highly personalized immunotherapies.
TL;DR: In this article, the authors used an in vivo "stress test" to challenge CD19-targeted T cells, and studied the functionality and persistence imparted by seven different CAR structures providing CD28 and/or 4-1BB costimulation.
TL;DR: It is demonstrated that antibodies reactive with the T cell-specific T3 antigen were insufficient to result in the activation of Jurkat cells, determined by the secretion of IL 2, demonstrating a two-stimulus requirement for gene expression in human T cells.
Abstract: The human T cell leukemia Jurkat was used as a model to examine the requirements of T cell activation. These studies demonstrated that antibodies reactive with the T cell-specific T3 antigen were insufficient to result in the activation of Jurkat cells, determined by the secretion of IL 2. IL 2 production occurred only in the presence of a second stimulus, the phorbol ester PMA. With the use of an IL 2-specific cDNA probe, the appearance of IL 2 RNA, similarly, occurred only when cells were stimulated with both anti-T3 antibodies and PMA. These results demonstrate a two-stimulus requirement for gene expression in human T cells.
TL;DR: A review of nanoparticle-based strategies to immune modulation in detail, and discuss the promise and outstanding challenges facing the field of immune engineering from a chemical biology/materials engineering perspective can be found in this article.
Abstract: 1.1 Progress and challenges in the new age of engineering immunity
The immune system plays a critical role in our health. No other component of human physiology plays a decisive role in as diverse an array of maladies, from deadly diseases with which we are all familiar to equally terrible esoteric conditions: HIV, malaria, pneumococcal and influenza infections; cancer; atherosclerosis; autoimmune diseases such as lupus, diabetes, and multiple sclerosis. The importance of understanding the function of the immune system and learning how to modulate immunity to protect against or treat disease thus cannot be overstated. Fortunately, we are entering an exciting era where the science of immunology is defining pathways for the rational manipulation of the immune system at the cellular and molecular level, and this understanding is leading to dramatic advances in the clinic that are transforming the future of medicine.1,2 These initial advances are being made primarily through biologic drugs– recombinant proteins (especially antibodies) or patient-derived cell therapies– but exciting data from preclinical studies suggest that a marriage of approaches based in biotechnology with the materials science and chemistry of nanomaterials, especially nanoparticles, could enable more effective and safer immune engineering strategies. This review will examine these nanoparticle-based strategies to immune modulation in detail, and discuss the promise and outstanding challenges facing the field of immune engineering from a chemical biology/materials engineering perspective.
1.1.1 Key cellular actors in the immune system
A brief summary of the cellular players in the immune response is worthwhile to preface the many immunomodulatory approaches described in this review. The immune system can be viewed at a high level as a collection of mobile cells that include members that traffic throughout the body in search of invading pathogens as well as cells that reside as sentinels at portals of entry (i.e. the airways, skin, gastrointestinal tract, etc.).3 These cells belong to one of two major arms, the innate immune system and adaptive immune system. Innate immune cells such as neutrophils and macrophages are poised to rapidly respond to pathogen invasion, expressing receptors that recognize conserved molecular motifs characteristic of bacteria, viruses, and fungi, to quickly phagocytose (internalize) microbes and secrete reactive oxygen species or cytokines that provide an immediate response to invading pathogens. The adaptive immune system is comprised of T-cells and B-cells, including CD4+ helper T-cells that secrete cytokines to direct the functions of innate cells, killer cells, and B-cells; and CD8+ killer T-cells that recognize and destroy infected or transformed cells. B-cells play a canonical role in vaccine responses by producing antibodies that bind to and neutralize the ability of microbes to invade host cells and/or promote their phagocytosis. The adaptive immune system is so named because of the clonal nature of T and B lymphocytes– each T-cell and B-cell expresses a unique T-cell receptor or B-cell receptor, respectively, which is generated in part by a process of stochastic DNA recombination, enabling the pool of lymphocytes the potential to recognize any microbial antigen they may encounter.4 When a T- or B-cell binds an antigen (essentially, any biological molecule from a microbe that is recognized by a T-cell receptor (TCR) or B-cell receptor (BCR)), this triggers massive proliferation of the antigen-specific cell, generating a pool of effectors within ~7 days following exposure. These effector T-cells and B-cells play an important role in backing up innate immune defenses to clear the invading pathogen. Following pathogen clearance, the majority of these cells (~90%) undergo programmed cell death, leaving a small pool of differentiated memory cells that can remain for the lifetime of the individual, to provide rapid recall protection if the same microbe is ever encountered again.5 A final key group of immune cells are the antigen presenting cells (APCs), and particularly a critical APC known as the dendritic cell, which is responsible for activating naive T-cells (and in some cases B-cells).6,7 Dendritic cells (DCs) are innate-like cells that reside in all peripheral tissues, and which act as sentinels, collecting antigens from the surrounding fluid and staying on constant alert for “danger signals”- molecular motifs signifying tissue damage or pathogen invasion. DCs and other immune cells express a host of receptors that specifically recognize danger signals to trigger their activation; the most studied among these receptors are the Toll-like receptors.8 If activated by danger signals, DCs migrate from their home tissue through the lymphatic vessels to local draining lymph nodes, where they physically present antigen to T-cells and B-cells. For T-cell activation, this is through the loading of short (8–15 amino acids) peptide fragments of antigens into the cleft of major histocompatibility complex (MHC) molecules displayed on the DC surface. These peptides are surveyed by the TCRs of T-cells, and on finding a cognate peptide, T-cells become activated by the DC to proliferate and carry out their effector functions.
The vastly complex set of cellular interactions summarized above (greatly oversimplified) is the network of interest to those interested in immune engineering, and in this review we aim to summarize the myriad ways in which materials scientists, chemical engineers, bioengineers, chemists, and physicists (often in collaboration with immunologists) are using nanomaterials as powerful tools to probe or manipulate immune responses for therapeutic ends. To set the stage for the rest of the review, we will briefly discuss two of the areas where synthetic nanoparticles have the prospect to play a significant role in the ongoing revolution of immunology in medicine– vaccines and active immunotherapy.
TL;DR: The ON-switch CAR exemplifies a simple and effective strategy to integrate cell-autonomous decision-making with exogenous, reversible user control and highlights the importance of developing optimized bio-inert, orthogonal control agents such as small molecules and light, together with their cellular cognate response components, in order to advance precision-controlled cellular therapeutics.
Abstract: There is growing interest in using engineered cells as therapeutic agents. For example, synthetic chimeric antigen receptors (CARs) can redirect T cells to recognize and eliminate tumor cells expressing specific antigens. Despite promising clinical results, these engineered T cells can exhibit excessive activity that is difficult to control and can cause severe toxicity. We designed "ON-switch" CARs that enable small-molecule control over T cell therapeutic functions while still retaining antigen specificity. In these split receptors, antigen-binding and intracellular signaling components assemble only in the presence of a heterodimerizing small molecule. This titratable pharmacologic regulation could allow physicians to precisely control the timing, location, and dosage of T cell activity, thereby mitigating toxicity. This work illustrates the potential of combining cellular engineering with orthogonal chemical tools to yield safer therapeutic cells that tightly integrate cell-autonomous recognition and user control.
TL;DR: In this paper, the authors investigated whether tumor-specific CD4+ T-cell reactivity is a common property in human melanoma and found that it is not common in most cases.
Abstract: Tumor-specific neo-antigens that arise as a consequence of mutations are thought to be important for the therapeutic efficacy of cancer immunotherapies. Accumulating evidence suggests that neo-antigens may be commonly recognized by intratumoral CD8+ T cells, but it is unclear whether neo-antigen-specific CD4+ T cells also frequently reside within human tumors. In view of the accepted role of tumor-specific CD4+ T-cell responses in tumor control, we addressed whether neo-antigen-specific CD4+ T-cell reactivity is a common property in human melanoma.
TL;DR: These findings provide promising first-in-human clinical experience for intracranial administration of IL13Rα2-specific CAR T cells for the treatment of GBM, establishing a foundation on which future refinements of adoptive CAR T-cell therapies can be applied.
Abstract: Purpose: A first-in-human pilot safety and feasibility trial evaluating chimeric antigen receptor (CAR)–engineered, autologous primary human CD8 + cytotoxic T lymphocytes (CTL) targeting IL13Rα2 for the treatment of recurrent glioblastoma (GBM). Experimental Design: Three patients with recurrent GBM were treated with IL13(E13Y)-zetakine CD8 + CTL targeting IL13Rα2. Patients received up to 12 local infusions at a maximum dose of 10 8 CAR-engineered T cells via a catheter/reservoir system. Results: We demonstrate the feasibility of manufacturing sufficient numbers of autologous CTL clones expressing an IL13(E13Y)-zetakine CAR for redirected HLA-independent IL13Rα2-specific effector function for a cohort of patients diagnosed with GBM. Intracranial delivery of the IL13-zetakine + CTL clones into the resection cavity of 3 patients with recurrent disease was well-tolerated, with manageable temporary brain inflammation. Following infusion of IL13-zetakine + CTLs, evidence for transient anti-glioma responses was observed in 2 of the patients. Analysis of tumor tissue from 1 patient before and after T-cell therapy suggested reduced overall IL13Rα2 expression within the tumor following treatment. MRI analysis of another patient indicated an increase in tumor necrotic volume at the site of IL13-zetakine + T-cell administration. Conclusions: These findings provide promising first-in-human clinical experience for intracranial administration of IL13Rα2-specific CAR T cells for the treatment of GBM, establishing a foundation on which future refinements of adoptive CAR T-cell therapies can be applied. Clin Cancer Res; 21(18); 4062–72. ©2015 AACR .
TL;DR: Macropinocytosis plays a key role in DC-mediated antigen presentation to T cells against pathogens and the efficiency of macropinocytes in antigen capture is regulated during the process of DC maturation.
Abstract: Dendritic cells (DCs) are outstanding antigen presenting cells (APCs) due to their robust ability to internalize extracellular antigens using endocytic processes such as receptor-mediated endocytosis, phagocytosis, and macropinocytosis. Macropinocytosis mediates the non-specific uptake of soluble antigens and occurs in DCs constitutively. Macropinocytosis plays a key role in DC-mediated antigen presentation to T cells against pathogens and the efficiency of macropinocytosis in antigen capture is regulated during the process of DC maturation. Here, we review the methods to study macropinocytosis, describe our current knowledge of the regulatory mechanisms of antigen uptake via macropinocytosis and the intracellular trafficking route followed by macropinocytosed antigens, and discuss the significance of macropinocytosis for DC function.
TL;DR: E engineered CAR-T cells to express HPSE and showed their improved capacity to degrade the ECM, which promoted tumor T cell infiltration and antitumor activity, and the use of this strategy may enhance the activity of CAR- T cells in individuals with stroma-rich solid tumors.
Abstract: Adoptive transfer of chimeric antigen receptor (CAR)-redirected T lymphocytes (CAR-T cells) has had less striking therapeutic effects in solid tumors than in lymphoid malignancies. Although active tumor-mediated immunosuppression may have a role in limiting the efficacy of CAR-T cells, functional changes in T lymphocytes after their ex vivo manipulation may also account for the reduced ability of cultured CAR-T cells to penetrate stroma-rich solid tumors compared with lymphoid tissues. We therefore studied the capacity of human in vitro-cultured CAR-T cells to degrade components of the extracellular matrix (ECM). In contrast to freshly isolated T lymphocytes, we found that in vitro-cultured T lymphocytes lack expression of the enzyme heparanase (HPSE), which degrades heparan sulfate proteoglycans, the main components of ECM. We found that HPSE mRNA is downregulated in in vitro-expanded T cells, which may be a consequence of p53 (officially known as TP53, encoding tumor protein 53) binding to the HPSE gene promoter. We therefore engineered CAR-T cells to express HPSE and showed their improved capacity to degrade the ECM, which promoted tumor T cell infiltration and antitumor activity. The use of this strategy may enhance the activity of CAR-T cells in individuals with stroma-rich solid tumors.
TL;DR: The applicability of TALEN-mediated genome editing to a scalable process enables the manufacturing of third-party CAR T-cell immunotherapies against arbitrary targets and can therefore be used in an "off-the-shelf" manner akin to other biologic immunopharmaceuticals.
Abstract: Adoptive immunotherapy using autologous T cells endowed with chimeric antigen receptors (CAR) has emerged as a powerful means of treating cancer. However, a limitation of this approach is that autologous CAR T cells must be generated on a custom-made basis. Here we show that electroporation of transcription activator-like effector nuclease (TALEN) mRNA allows highly efficient multiplex gene editing in primary human T cells. We use this TALEN-mediated editing approach to develop a process for the large-scale manufacturing of T cells deficient in expression of both their αβ T-cell receptor (TCR) and CD52, a protein targeted by alemtuzumab, a chemotherapeutic agent. Functionally, T cells manufactured with this process do not mediate graft-versus-host reactions and are rendered resistant to destruction by alemtuzumab. These characteristics enable the administration of alemtuzumab concurrently or prior to engineered T cells, supporting their engraftment. Furthermore, endowing the TALEN-engineered cells with a CD19 CAR led to efficient destruction of CD19(+) tumor targets even in the presence of the chemotherapeutic agent. These results demonstrate the applicability of TALEN-mediated genome editing to a scalable process, which enables the manufacturing of third-party CAR T-cell immunotherapies against arbitrary targets. As such, CAR T-cell immunotherapies can therefore be used in an "off-the-shelf" manner akin to other biologic immunopharmaceuticals
TL;DR: The results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8⁺ T cells and CD8¹ TILs in melanoma patients and suggest that dual TIGit andPD-1 blockade should be further explored to elicit potent antitumor CD8 ™ T cell responses in patients with advanced melanoma.
Abstract: T cell Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed by activated T cells, Tregs, and NK cells. Here, we determined that TIGIT is upregulated on tumor antigen-specific (TA-specific) CD8⁺ T cells and CD8⁺ tumor-infiltrating lymphocytes (TILs) from patients with melanoma, and these TIGIT-expressing CD8⁺ T cells often coexpress the inhibitory receptor PD-1. Moreover, CD8⁺ TILs from patients exhibited downregulation of the costimulatory molecule CD226, which competes with TIGIT for the same ligand, supporting a TIGIT/CD226 imbalance in metastatic melanoma. TIGIT marked early T cell activation and was further upregulated by T cells upon PD-1 blockade and in dysfunctional PD-1⁺TIM-3⁺ TA-specific CD8⁺ T cells. PD-1⁺TIGIT⁺, PD-1⁻TIGIT⁺, and PD-1⁺TIGIT⁻ CD8⁺ TILs had similar functional capacities ex vivo, suggesting that TIGIT alone, or together with PD-1, is not indicative of T cell dysfunction. However, in the presence of TIGIT ligand-expressing cells, TIGIT and PD-1 blockade additively increased proliferation, cytokine production, and degranulation of both TA-specific CD8⁺ T cells and CD8⁺ TILs. Collectively, our results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8⁺ T cells and CD8⁺ TILs in melanoma patients and suggest that dual TIGIT and PD-1 blockade should be further explored to elicit potent antitumor CD8⁺ T cell responses in patients with advanced melanoma.
TL;DR: The complementary effects of radiation on priming and effector phases of antitumor immunity make it an appealing strategy to generate immunity against a patient's own individual tumor, that through immunological memory, can result in long-lasting systemic responses.
Abstract: The recent success of cancer immunotherapy has demonstrated the power of the immune system to clear tumors, generating renewed enthusiasm for identifying ways to induce antitumor immune responses in patients. Natural antitumor immune responses are detectable in a fraction of patients across multiple malignant neoplasms and can be reactivated by targeting rate-limiting immunosuppressive mechanisms. In most patients, however, interventions to induce a de novo antitumor immune response are necessary. We review growing evidence that radiation therapy targeted to the tumor can convert it into an in situ tumor vaccine by inducing release of antigens during cancer cell death in association with proinflammatory signals that trigger the innate immune system to activate tumor-specific T cells. In addition, radiation’s effects on the tumor microenvironment enhance infiltration of activated T cells and can overcome some of the barriers to tumor rejection. Thus, the complementary effects of radiation on priming and effector phases of antitumor immunity make it an appealing strategy to generate immunity against a patient’s own individual tumor, that through immunological memory, can result in long-lasting systemic responses. Several anecdotal cases have demonstrated the efficacy of combining radiation with available immunotherapies, and results of prospective trials are forthcoming.
TL;DR: The ability of stereotactic XRT to induce endogenous antigen-specific immune responses when it is combined with anti–PD-1 checkpoint blockade immunotherapy is demonstrated and provides an additional mechanistic rationale for combining radiation with PD-1 blockade in the clinic.
Abstract: The immune-modulating effects of radiotherapy (XRT) have gained considerable interest recently, and there have been multiple reports of synergy between XRT and immunotherapy. However, additional preclinical studies are needed to demonstrate the antigen-specific nature of radiation-induced immune responses and elucidate potential mechanisms of synergy with immunotherapy. Here, we demonstrate the ability of stereotactic XRT to induce endogenous antigen-specific immune responses when it is combined with anti-PD-1 checkpoint blockade immunotherapy. Using the small animal radiation research platform (SARRP), image-guided stereotactic XRT delivered to B16-OVA melanoma or 4T1-HA breast carcinoma tumors resulted in the development of antigen-specific T cell- and B cell-mediated immune responses. These immune-stimulating effects of XRT were significantly increased when XRT was combined with either anti-PD-1 therapy or regulatory T cell (Treg) depletion, resulting in improved local tumor control. Phenotypic analyses of antigen-specific CD8 T cells revealed that XRT increased the percentage of antigen-experienced T cells and effector memory T cells. Mechanistically, we found that XRT upregulates tumor-associated antigen-MHC complexes, enhances antigen cross-presentation in the draining lymph node, and increases T-cell infiltration into tumors. These findings demonstrate the ability of XRT to prime an endogenous antigen-specific immune response and provide an additional mechanistic rationale for combining radiation with PD-1 blockade in the clinic.
TL;DR: The identification of mutated and aberrantly expressed self-tumor antigens has been a time consuming and laborious task as mentioned in this paper, which has been solved by using next-generation sequencing and epitope prediction.
Abstract: It is now well established that the immune system can recognize developing cancers and that therapeutic manipulation of immunity can induce tumor regression. The capacity to manifest remarkably durable responses in some patients has been ascribed in part to T cells that can (a) kill tumor cells directly, (b) orchestrate diverse antitumor immune responses, (c) manifest long-lasting memory, and (d) display remarkable specificity for tumor-derived proteins. This specificity stems from fundamental differences between cancer cells and their normal counterparts in that the former develop protein-altering mutations and undergo epigenetic and genetic alterations, resulting in aberrant protein expression. These events can result in formation of tumor antigens. The identification of mutated and aberrantly expressed self-tumor antigens has historically been time consuming and laborious. While mutant antigens are usually expressed in a tumor-specific manner, aberrantly expressed antigens are often shared between cancers and, therefore, in the past, have been the major focus of therapeutic cancer vaccines. However, advances in next-generation sequencing and epitope prediction now permit the rapid identification of mutant tumor neoantigens. This review focuses on a discussion of mutant tumor neoantigens and their use in personalizing cancer immunotherapies.
TL;DR: It is demonstrated that the transcription factor NFAT controls the program of T cell exhaustion and promotes T cell anergy and exhaustion by binding at sites that do not require cooperation with AP-1.
TL;DR: A patient with refractory multiple myeloma received an infusion of CTL019 cells, a cellular therapy consisting of autologous T cells transduced with an anti-CD19 chimeric antigen receptor, after myeloablative chemotherapy and autOLOGous stem-cell transplantation, which led to a complete response.
Abstract: A patient with refractory multiple myeloma received an infusion of CTL019 cells, a cellular therapy consisting of autologous T cells transduced with an anti-CD19 chimeric antigen receptor, after myeloablative chemotherapy (melphalan, 140 mg per square meter of body-surface area) and autologous stem-cell transplantation Four years earlier, autologous transplantation with a higher melphalan dose (200 mg per square meter) had induced only a partial, transient response Autologous transplantation followed by treatment with CTL019 cells led to a complete response with no evidence of progression and no measurable serum or urine monoclonal protein at the most recent evaluation, 12 months after treatment This response was achieved despite the absence of CD19 expression in 9995% of the patient's neoplastic plasma cells (Funded by Novartis and others; ClinicalTrialsgov number, NCT02135406)
TL;DR: Adjuvants are the most advanced new technology in the search for new vaccines against challenging pathogens and for vulnerable populations that respond poorly to traditional vaccines.
TL;DR: In this article, the authors showed that CEACAM1 facilitates the maturation and cell surface expression of TIM-3 by forming a heterodimeric interaction in cis through the highly related membrane-distal N-terminal domains of each molecule.
Abstract: T-cell immunoglobulin domain and mucin domain-3 (TIM-3, also known as HAVCR2) is an activation-induced inhibitory molecule involved in tolerance and shown to induce T-cell exhaustion in chronic viral infection and cancers. Under some conditions, TIM-3 expression has also been shown to be stimulatory. Considering that TIM-3, like cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1), is being targeted for cancer immunotherapy, it is important to identify the circumstances under which TIM-3 can inhibit and activate T-cell responses. Here we show that TIM-3 is co-expressed and forms a heterodimer with carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1), another well-known molecule expressed on activated T cells and involved in T-cell inhibition. Biochemical, biophysical and X-ray crystallography studies show that the membrane-distal immunoglobulin-variable (IgV)-like amino-terminal domain of each is crucial to these interactions. The presence of CEACAM1 endows TIM-3 with inhibitory function. CEACAM1 facilitates the maturation and cell surface expression of TIM-3 by forming a heterodimeric interaction in cis through the highly related membrane-distal N-terminal domains of each molecule. CEACAM1 and TIM-3 also bind in trans through their N-terminal domains. Both cis and trans interactions between CEACAM1 and TIM-3 determine the tolerance-inducing function of TIM-3. In a mouse adoptive transfer colitis model, CEACAM1-deficient T cells are hyper-inflammatory with reduced cell surface expression of TIM-3 and regulatory cytokines, and this is restored by T-cell-specific CEACAM1 expression. During chronic viral infection and in a tumour environment, CEACAM1 and TIM-3 mark exhausted T cells. Co-blockade of CEACAM1 and TIM-3 leads to enhancement of anti-tumour immune responses with improved elimination of tumours in mouse colorectal cancer models. Thus, CEACAM1 serves as a heterophilic ligand for TIM-3 that is required for its ability to mediate T-cell inhibition, and this interaction has a crucial role in regulating autoimmunity and anti-tumour immunity.