Human Leukocyte Antigen (HLA) A*1101-Restricted Epstein-Barr Virus-Specific T-cell Receptor Gene Transfer to Target Nasopharyngeal Carcinoma

An EBV-related CD4 TCR immunotherapy inhibits tumor growth in an HLA-DP5+ nasopharyngeal cancer mouse model

Adoptive transfer of T cell receptor-engineered T cells (TCR-T) is a promising strategy for immunotherapy against solid tumors. However, the potential of CD4+ T cells in mediating tumor regression has been neglected. Nasopharyngeal cancer is consistently associated with EBV. Here, to evaluate the therapeutic potential of CD4 TCR-T in nasopharyngeal cancer, we screened for CD4 TCRs recognizing EBV nuclear antigen 1 (EBNA1) presented by HLA-DP5. Using mass spectrometry, we identified EBNA1567-581, a peptide naturally processed and presented by HLA-DP5. We isolated TCR135, a CD4 TCR with high functional avidity, that can function in both CD4+ and CD8+ T cells and recognizes HLA-DP5-restricted EBNA1567-581. TCR135-transduced T cells functioned in two ways: directly killing HLA-DP5+EBNA1+ tumor cells after recognizing EBNA1 presented by tumor cells and indirectly killing HLA-DP5-negative tumor cells after recognizing EBNA1 presented by antigen-presenting cells. TCR135-transduced T cells preferentially infiltrated into the tumor microenvironment and significantly inhibited tumor growth in xenograft nasopharyngeal tumor models. Additionally, we found that 62% of nasopharyngeal cancer patients showed 50%-100% expression of HLA-DP on tumor cells, indicating that nasopharyngeal cancer is well suited for CD4 TCR-T therapy. These findings suggest that TCR135 may provide a new strategy for EBV-related nasopharyngeal cancer immunotherapy in HLA-DP5+ patients.

Update of Natural Products and Their Derivatives Targeting Epstein-Barr Infection

Epstein-Barr (EBV) is a human γ-herpesvirus that undergoes both a productive (lytic) cycle and a non-productive (latent) phase. The virus establishes enduring latent infection in B lymphocytes and productive infection in the oral mucosal epithelium. Like other herpesviruses, EBV expresses its genes in a coordinated pattern during acute infection. Unlike others, it replicates its DNA during latency to maintain the viral genome in an expanding pool of B lymphocytes, which are stimulated to divide upon infection. The reactivation from the latent state is associated with a productive gene expression pattern mediated by virus-encoded transcriptional activators BZLF-1 and BRLF-1. EBV is a highly transforming virus that contributes to the development of human lymphomas. Though viral vectors and mRNA platforms have been used to develop an EBV prophylactic vaccine, currently, there are no vaccines or antiviral drugs for the prophylaxis or treatment of EBV infection and EBV-associated cancers. Natural products and bioactive compounds are widely studied for their antiviral potential and capability to modulate intracellular signaling pathways. This review was intended to collect information on plant-derived products showing their antiviral activity against EBV and evaluate their feasibility as an alternative or adjuvant therapy against EBV infections and correlated oncogenesis in humans.

Virus-specific T-cells from third party or transplant donors for treatment of EBV lymphoproliferative diseases arising post hematopoietic cell or solid organ transplantation

EBV+ lymphomas constitute a significant cause of morbidity and mortality in recipients of allogeneic hematopoietic cell (HCT) and solid organ transplants (SOT). Phase I and II trials have shown that in HCT recipients, adoptive transfer of EBV-specific T-cells from the HCT donor can safely induce durable remissions of EBV+ lymphomas including 70->90% of patients who have failed to respond to treatment with Rituximab. More recently, EBV-specific T-cells generated from allogeneic 3rd party donors have also been shown to induce durable remission of EBV+ lymphomas in Rituximab refractory HCT and SOT recipients. In this review, we compare results of phase I and II trials of 3rd party and donor derived EBV-specific T-cells. We focus on the attributes and limitations of each product in terms of access, safety, responses achieved and durability. The limited data available regarding donor and host factors contributing to T cell persistence is also described. We examine factors contributing to treatment failures and approaches to prevent or salvage relapse. Lastly, we summarize strategies to further improve results for virus-specific immunotherapies for post-transplant EBV lymphomas.

Adoptive cell therapy in paediatric extracranial solid tumours: current approaches and future challenges

Immunotherapy has ignited hope to cure paediatric solid tumours that resist traditional therapies. Among the most promising methods is adoptive cell therapy (ACT). Particularly, ACT using T cells equipped with chimeric antigen receptors (CARs) has moved into the spotlight in clinical studies. However, the efficacy of ACT is challenged by ACT-intrinsic factors, like lack of activation or T cell exhaustion, as well as immune evasion strategies of paediatric solid tumours, such as their highly immunosuppressive microenvironment. Novel strategies, including ACT using innate-like lymphocytes, innovative cell engineering techniques, and ACT combination therapies, are being developed and will be crucial to overcome these challenges. Here, we discuss the main classes of ACT for the treatment of paediatric extracranial solid tumours, reflect on the available preclinical and clinical evidence supporting promising strategies, and address the challenges that ACT is still facing. Ultimately, we highlight state-of-the-art developments and opportunities for new therapeutic options, which hold great potential for improving outcomes in this challenging patient population.

EBV-induced T-cell responses in EBV-specific and nonspecific cancers

Epstein-Barr virus (EBV) is a ubiquitous human tumor virus associated with various malignancies, including B-lymphoma, NK and T-lymphoma, and epithelial carcinoma. It infects B lymphocytes and epithelial cells within the oropharynx and establishes persistent infection in memory B cells. With a balanced virus-host interaction, most individuals carry EBV asymptomatically because of the lifelong surveillance by T cell immunity against EBV. A stable anti-EBV T cell repertoire is maintained in memory at high frequency in the blood throughout persistent EBV infection. Patients with impaired T cell immunity are more likely to develop life-threatening lymphoproliferative disorders, highlighting the critical role of T cells in achieving the EBV-host balance. Recent studies reveal that the EBV protein, LMP1, triggers robust T-cell responses against multiple tumor-associated antigens (TAAs) in B cells. Additionally, EBV-specific T cells have been identified in EBV-unrelated cancers, raising questions about their role in antitumor immunity. Herein, we summarize T-cell responses in EBV-related cancers, considering latency patterns, host immune status, and factors like human leukocyte antigen (HLA) susceptibility, which may affect immune outcomes. We discuss EBV-induced TAA-specific T cell responses and explore the potential roles of EBV-specific T cell subsets in tumor microenvironments. We also describe T-cell immunotherapy strategies that harness EBV antigens, ranging from EBV-specific T cells to T cell receptor-engineered T cells. Lastly, we discuss the involvement of γδ T-cells in EBV infection and associated diseases, aiming to elucidate the comprehensive interplay between EBV and T-cell immunity.

The role of Epstein-Barr virus in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a metastasis-prone malignancy closely associated with the Epstein-Barr virus (EBV). Despite ubiquitous infection of EBV worldwide, NPC incidences displayed predominance in certain ethnic groups and endemic regions. The majority of NPC patients are diagnosed with advanced-stage disease, as a result of anatomical isolation and non-specific clinical manifestation. Over the decades, researchers have gained insights into the molecular mechanisms underlying NPC pathogenesis as a result of the interplay of EBV infection with several environmental and genetic factors. EBV-associated biomarkers were also used for mass population screening for the early detection of NPC. EBV and its encoded products also serve as potential targets for the development of therapeutic strategies and tumour-specific drug delivery. This review will discuss the pathogenic role of EBV in NPC and efforts in exploiting the potential of EBV-associated molecules as biomarkers and therapeutic targets. The current knowledge on the role of EBV and its associated products in NPC tumorigenesis, development and progression will offer a new outlook and potential intervention strategy against this EBV-associated malignancy.

Targeting Driver Oncogenes and Other Public Neoantigens Using T Cell Receptor-Based Cellular Therapy

T cell reactivity to tumor-specific neoantigens can drive endogenous and therapeutically induced antitumor immunity. However, most tumor-specific neoantigens are unique to each patient (private) and targeting them requires personalized therapy. A smaller subset of neoantigens includes epitopes that span recurrent mutation hotspots, translocations, or gene fusions in oncogenic drivers and tumor suppressors, as well as epitopes that arise from viral oncogenic proteins. Such antigens are likely to be shared across patients (public), uniformly expressed within a tumor, and required for cancer cell survival and fitness. Although a limited number of these public neoantigens are naturally immunogenic, recent studies affirm their clinical utility. In this review, we highlight efforts to target mutant KRAS, mutant p53, and epitopes derived from oncogenic viruses using T cells engineered with off-the-shelf T cell receptors. We also discuss the challenges and strategies to achieving more effective T cell therapies, particularly in the context of solid tumors.

Immune landscape of viral cancers: Insights from single-cell sequencing

Viral infections trigger a wide range of immune responses thought to drive tumorigenesis and malignant progression. Dissecting virus-induced changes in the tumor immune microenvironment (TIME) is therefore crucial to identify key leukocyte populations that may represent novel targets for cancer therapy. Single-cell sequencing approaches have now been widely applied to the analysis of various tumors, thus enabling multiomics characterization of the highly heterogeneous TIME that bulk-sequencing cannot fully elucidate. In this review, we summarized key recent findings from sequencing studies of the immune infiltrate and antitumor response in virus-associated cancers at single cell resolution. Additionally, we also reviewed recent developments in immunotherapy for virus-associated cancers. We anticipate that the strategic use of single-cell sequencing will advance our understanding of the TIME of viral cancers, leading to the development of more potent novel treatments.

MET-Induced CD73 Restrains STING-Mediated Immunogenicity of EGFR-Mutant Lung Cancer

Immunotherapy has shown limited efficacy in patients with EGFR-mutated lung cancer. Efforts to enhance the immunogenicity of EGFR-mutated lung cancer have been unsuccessful to date. Here, we discover that MET amplification, the most common mechanism of resistance to third-generation EGFR tyrosine kinase inhibitors (TKI), activates tumor cell STING, an emerging determinant of cancer immunogenicity (1). However, STING activation was restrained by ectonucleosidase CD73, which is induced in MET-amplified, EGFR-TKI-resistant cells. Systematic genomic analyses and cell line studies confirmed upregulation of CD73 in MET-amplified and MET-activated lung cancer contexts, which depends on coinduction of FOSL1. Pemetrexed (PEM), which is commonly used following EGFR-TKI treatment failure, was identified as an effective potentiator of STING-dependent TBK1-IRF3-STAT1 signaling in MET-amplified, EGFR-TKI-resistant cells. However, PEM treatment also induced adenosine production, which inhibited T-cell responsiveness. In an allogenic humanized mouse model, CD73 deletion enhanced immunogenicity of MET-amplified, EGFR-TKI-resistant cells, and PEM treatment promoted robust responses regardless of CD73 status. Using a physiologic antigen recognition model, inactivation of CD73 significantly increased antigen-specific CD8+ T-cell immunogenicity following PEM treatment. These data reveal that combined PEM and CD73 inhibition can co-opt tumor cell STING induction in TKI-resistant EGFR-mutated lung cancers and promote immunogenicity.

SIGNIFICANCE

MET amplification upregulates CD73 to suppress tumor cell STING induction and T-cell responsiveness in TKI-resistant, EGFR-mutated lung cancer, identifying a strategy to enhance immunogenicity and improve treatment.

EBV-associated diseases: Current therapeutics and emerging technologies

EBV is a prevalent virus, infecting >90% of the world's population. This is an oncogenic virus that causes ~200,000 cancer-related deaths annually. It is, in addition, a significant contributor to the burden of autoimmune diseases. Thus, EBV represents a significant public health burden. Upon infection, EBV remains dormant in host cells for long periods of time. However, the presence or episodic reactivation of the virus increases the risk of transforming healthy cells to malignant cells that routinely escape host immune surveillance or of producing pathogenic autoantibodies. Cancers caused by EBV display distinct molecular behaviors compared to those of the same tissue type that are not caused by EBV, presenting opportunities for targeted treatments. Despite some encouraging results from exploration of vaccines, antiviral agents and immune- and cell-based treatments, the efficacy and safety of most therapeutics remain unclear. Here, we provide an up-to-date review focusing on underlying immune and environmental mechanisms, current therapeutics and vaccines, animal models and emerging technologies to study EBV-associated diseases that may help provide insights for the development of novel effective treatments.

Epstein Barr Virus: Development of Vaccines and Immune Cell Therapy for EBV-Associated Diseases

Epstein-Barr virus (EBV) is the first human tumor virus discovered and is strongly implicated in the etiology of multiple lymphoid and epithelial cancers. Each year EBV associated cancers account for over 200,000 new cases of cancer and cause 150,000 deaths world-wide. EBV is also the primary cause of infectious mononucleosis, and up to 70% of adolescents and young adults in developed countries suffer from infectious mononucleosis. In addition, EBV has been shown to play a critical role in the pathogenesis of multiple sclerosis. An EBV prophylactic vaccine that induces neutralizing antibodies holds great promise for prevention of EBV associated diseases. EBV envelope proteins including gH/gL, gB and gp350 play key roles in EBV entry and infection of target cells, and neutralizing antibodies elicited by each of these proteins have shown to prevent EBV infection of target cells and markedly decrease EBV titers in the peripheral blood of humanized mice challenged with lethal dose EBV. Recent studies demonstrated that immunization with the combination of gH/gL, gB and/or gp350 induced markedly increased synergistic EBV neutralizing activity compared to immunization with individual proteins. As previous clinical trials focused on gp350 alone were partially successful, the inclusion of gH/gL and gB in a vaccine formulation with gp350 represents a promising approach of EBV prophylactic vaccine development. Therapeutic EBV vaccines have also been tested clinically with encouraging results. Immunization with various vaccine platforms expressing the EBV latent proteins EBNA1, LMP1, and/or LMP2 promoted specific CD4+ and CD8+ cytotoxic responses with anti-tumor activity. The addition of EBV envelope proteins gH/gL, gB and gp350 has the potential to increase the efficacy of a therapeutic EBV vaccine. The immune system plays a critical role in the control of tumors, and immune cell therapy has emerged as a promising treatment of cancers. Adoptive T-cell therapy has been successfully used in the prevention and treatment of post-transplant lymphoproliferative disorder. Chimeric antigen receptor T cell therapy and T cell receptor engineered T cell therapy targeting EBV latent proteins LMP1, LMP2 and/or EBNA1 have been in development, with the goal to increase the specificity and efficacy of treatment of EBV associated cancers.

CD4-positive lymphoepithelial-like carcinoma: Report of unusual case

We are reporting an unusual case of lymphoepithelial-like carcinoma (LELC) in an 8-year-old female patient where the tumor cells showed unusual CD4 expression. The lesion was found in the left submandibular neck region, in the vicinity of the submandibular gland. The salivary gland was not infiltrated by the tumor, and the tumor exhibited a classic LELC with single and clusters of tumor cells surrounded by many hematolymphoid cells. The tumor cells revealed strong positivity for Epstein-Bar virus as confirmed by the EBER: Epstein-Barr Virus in situ hybridization (EBER-ISH) method of staining. Interestingly, the tumor cells expressed membranous immunostaining for the T-helper lymphocyte antibody (CD4) in addition to pan-cytokeratin. A brief discussion about this unusual finding is offered. The patient was treated as a case of Epstein-Bar virus-associated nasopharyngeal carcinoma with excellent response.

Induction of EBV latent membrane protein-2A (LMP2A)-specific T cells and construction of individualized TCR-engineered T cells for EBV-associated malignancies

Background

Latent membrane protein-2A (LMP2A)-specific TCR-engineered T cells could be a promising treatment approach to Epstein–Barr virus-associated malignancies. However, previous studies mainly reported LMP2A-reactive TCRs only focusing on specific HLA subtypes and corresponding epitopes, and thus, they were only suitable for patients with specific HLA.

Methods

Due to hugely varied HLA subtypes and presented LMP2A epitopes in different individuals, our study attempted to develop an individualized approach, based on the weekly in vitro stimulation of peripheral T cells for 2 weeks with autologous dendritic cells (DCs) pulsed with a pool of LMP2A peptides covering LMP2A whole protein and combination analysis of high throughput TCRβ sequencing of prestimulated and poststimulated T cells and single-cell TCR sequencing of poststimulated T cells, and to identify LMP2A-specific TCRs of which poststimulated frequencies significantly increased than corresponding prestimulated frequencies.

Results

Following this approach, multiple LMP2A-reactive TCRs were identified, optimized and cloned into lentiviral vector, and then transduced into peripheral T cells. These engineerd T cells were demonstrated to specifically recognize the LMP2A presented by autologous DCs and lymphoblastoid cell lines in vitro and in vivo.

Conclusions

This approach provides an efficient procedure to isolate individualized LMP2A-specific TCRs for basic and translational research, as well as for clinical applications.

Advances in Adoptive Cell Therapy for Head and Neck Cancer

This article reviews the most recent literature describing clinical advances in adoptive cell therapy for patients with head and neck cancer. Clinical trials with tumor-infiltrating lymphocyte and gene-engineered T-cell receptor T-cell therapy are highlighted.

Generation of Epstein-Barr Virus Antigen-Specific T Cell Receptors Recognizing Immunodominant Epitopes of LMP1, LMP2A, and EBNA3C for Immunotherapy

Epstein-Barr virus (EBV) infections in healthy individuals are usually cleared by immune cells, wherein CD8⁺ T lymphocytes play the most important role. However, in some immunocompromised individuals, EBV infections can lead to the development of cancer in B, T, natural killer (NK) cells and epithelial cells. Most EBV-associated cancers express a limited number of virus-specific antigens such as latent membrane proteins (LMP1 and LMP2) and nuclear proteins (EBNA1, -2, EBNA3A, -B, -C, and EBNA-LP). These antigens represent true tumor-specific antigens and can be considered useful targets for T cell receptor (TCR) gene therapy to treat EBV-associated diseases. We used a TCR isolation platform based on a single major histocompatibility complex class I (MHC I) K562 cell library for the detection, isolation, and re-expression of TCRs targeting immunodominant peptide MHC (pMHC). Mature dendritic cells (mDCs) were pulsed with in vitro-transcribed (ivt) RNA encoding for the selected antigen to stimulate autologous T cells. The procedure allowed the mDCs to select an immunogenic epitope of the antigen for processing and presentation on the cell surface in combination with the most suitable MHC I molecule. We isolated eight EBV-specific TCRs. They recognize various pMHCs of EBV antigens LMP1, LMP2A, and EBNA3C, some of them described previously and some newly identified in this study. The TCR genes were molecularly cloned into retroviral vectors and the resultant TCR-engineered T cells secreted interferon-γ after antigen contact and were able to lyse tumor cells. The EBV-specific TCRs can be used as a basis for the generation of a TCR library, which provides a valuable source of TCRs for the production of EBV-specific T cells to treat EBV-associated diseases in patients with different MHC I types.

CAR T cells targeting tumor endothelial marker CLEC14A inhibit tumor growth

Engineering T cells to express chimeric antigen receptors (CARs) specific for antigens on hematological cancers has yielded remarkable clinical responses, but with solid tumors, benefit has been more limited. This may reflect lack of suitable target antigens, immune evasion mechanisms in malignant cells, and/or lack of T cell infiltration into tumors. An alternative approach, to circumvent these problems, is targeting the tumor vasculature rather than the malignant cells directly. CLEC14A is a glycoprotein selectively overexpressed on the vasculature of many solid human cancers and is, therefore, of considerable interest as a target antigen. Here, we generated CARs from 2 CLEC14A-specific antibodies and expressed them in T cells. In vitro studies demonstrated that, when exposed to their target antigen, these engineered T cells proliferate, release IFN-γ, and mediate cytotoxicity. Infusing CAR engineered T cells into healthy mice showed no signs of toxicity, yet these T cells targeted tumor tissue and significantly inhibited tumor growth in 3 mouse models of cancer (Rip-Tag2, mPDAC, and Lewis lung carcinoma). Reduced tumor burden also correlated with significant loss of CLEC14A expression and reduced vascular density within malignant tissues. These data suggest the tumor vasculature can be safely and effectively targeted with CLEC14A-specific CAR T cells, offering a potent and widely applicable therapy for cancer.

T cells expressing a chimeric antigen receptor specific for the tumor vascular marker CLEC14A inhibited tumor growth in three mouse cancer models.

Identification of Functional HLA-A*01 :01-Restricted EBV-LMP2-Specific T-cell Receptors

BACKGROUND

Adoptive transfer of genetically engineered T cells expressing antigen-specific T-cell receptors (TCRs), is an appealing therapeutic approach for Epstein-Barr virus (EBV)-associated malignancies of latency type II/III that express EBV-antigens (LMP1/2). Patients who are HLA-A*01:01pos could benefit from such products, since no T cells recognizing any EBV-derived peptide in this common HLA allele have been found thus far.

METHODS

HLA-A*01:01-restricted EBV-(LMP2)-specific T-cells were isolated using peptide-MHC-tetramers. Functionality was assessed by production of IFNγ and cytotoxicity when stimulated with EBV-LMP2-expressing cell-lines. Functionality of primary T cells transduced with HLA-A*01:01-restricted EBV-LMP2-specific TCRs was optimized by knocking out the endogenous TCR of primary T cells (ΔTCR) using CRISPR-Cas9 technology.

RESULTS

EBV-LMP2-specific T cells were successfully isolated and their TCRs were characterized. TCR gene-transfer in primary T cells resulted in specific peptide-MHC-tetramer binding and reactivity against EBV-LMP2-expressing cell-lines. The mean-fluorescence intensity of peptide-MHC-tetramer binding was increased 1.5-2 fold when the endogenous TCR of CD8pos T cells was knocked out. CD8pos/ΔTCR T cells modified to express EBV-LMP2-specific TCRs showed IFNγ secretion and cytotoxicity towards EBV-LMP2-expressing malignant cell-lines.

DISCUSSION

We isolated the first functional HLA-A*01:01-restricted EBV-LMP2-specific T-cell populations and TCRs, which can potentially be used in future TCR gene-therapy to treat EBV-associated latency type II/III malignancies.

Redirecting T Cells against Epstein-Barr Virus Infection and Associated Oncogenesis

The Epstein-Barr virus (EBV) is associated with lymphomas and carcinomas. For some of these, the adoptive transfer of EBV specific T cells has been therapeutically explored, with clinical success. In order to avoid naturally occurring EBV specific autologous T cell selection from every patient, the transgenic expression of latent and early lytic viral antigen specific T cell receptors (TCRs) to redirect T cells, to target the respective tumors, is being developed. Recent evidence suggests that not only TCRs against transforming latent EBV antigens, but also against early lytic viral gene products, might be protective for the control of EBV infection and associated oncogenesis. At the same time, these approaches might be more selective and cause less collateral damage than targeting general B cell markers with chimeric antigen receptors (CARs). Thus, EBV specific TCR transgenic T cells constitute a promising therapeutic strategy against EBV associated malignancies.

Targeting Cancer with Genetically Engineered TCR T Cells

The adoptive cell transfer (ACT) of genetically engineered T cell receptor (TCR) T cells is one of the burgeoning fields of immunotherapy, with promising results in current clinical trials. Presently, clinicaltrials.gov has over 200 active trials involving adoptive cell therapy. The ACT of genetically engineered T cells not only allows the ability to select for TCRs with desired properties such as high-affinity receptors and tumor reactivity but to further enhance those receptors allowing for better targeting and killing of cancer cells in patients. Moreover, the addition of genetic material, including cytokines and cytokine receptors, can increase the survival and persistence of the T cell allowing for complete and sustained remission of cancer targets. The potential for improvement in adoptive cell therapy is limitless, with genetic modifications targeting to improve weaknesses of ACT and to thus enhance receptor affinity and functional avidity of the genetically engineered T cells.

Current Perspectives in Cancer Immunotherapy

Different immunotherapeutic approaches have proved to be of significant clinical value to many patients with different types of advanced cancer. However, we need more precise immunotherapies and predictive biomarkers to increase the successful response rates. The advent of next generation sequencing technologies and their applications in immuno-oncology has helped us tremendously towards this aim. We are now moving towards the realization of personalized medicine, thus, significantly increasing our expectations for a more successful management of the disease. Here, we discuss the current immunotherapeutic approaches against cancer, including immune checkpoint blockade with an emphasis on anti-PD-L1 and anti-CTLA-4 monoclonal antibodies. We also analyze a growing list of other co-inhibitory and co-stimulatory markers and emphasize the mechanism of action of the principal pathway for each of these, as well as on drugs that either have been FDA-approved or are under clinical investigation. We further discuss recent advances in other immunotherapies, including cytokine therapy, adoptive cell transfer therapy and therapeutic vaccines. We finally discuss the modulation of gut microbiota composition and response to immunotherapy, as well as how tumor-intrinsic factors and immunological processes influence the mutational and epigenetic landscape of progressing tumors and response to immunotherapy but also how immunotherapeutic intervention influences the landscape of cancer neoepitopes and tumor immunoediting.

Immune reconstitution of HLA-A*0201/BMLF1- and HLA-A*1101/LMP2-specific Epstein Barr virus cytotoxic T lymphocytes within 90 days after haploidentical hematopoietic stem cell transplantation

Background

Haploidentical hematopoietic stem cell transplant (haplo-HSCT) recipients are at high risk for Epstein Barr virus (EBV)-related diseases. EBV-specific CD8⁺ cytotoxic T cells can control EBV-infected B cell expansion; however, no studies have investigated EBV-specific immune reconstitution after HSCT, particularly haplo-HSCT. Therefore, in this study, we aimed to characterize EBV-specific immune cell reconstitution after haplo-HSCT.

Methods

HLA-A*1101 and HLA-A*0201 pentamers folded with immunodominant EBV peptides were used to detect EBV-specific CD8⁺ T cells by flow cytometry in peripheral blood mononuclear cells from 19 haplo-HSCT recipients and the results were compared with those in controls. We also compared the EBV-specific pentamer-binding cell frequencies in patients with or without EBV-related diseases by flow cytometry.

Results

Pentamer-binding EBV-specific CD8⁺ T cells were detected at + 30, + 60 and + 90 days after haplo-HSCT in EBV-seropositive patients subjected to haplo-HSCT from an EBV-seropositive donor. The frequencies of the HLA-A*0201/BMLF1-GLC pentamer in haplo-HSCT patients at + 30 days were significantly lower than those in HLA-A*0201-positive healthy controls (p = 0.019) and patients at + 60 days (p = 0.003). The frequencies of the HLA-A*1101/LMP2-SSC pentamer at + 30, + 60, and + 90 days were significantly decreased compared with those in healthy controls (p = 0.009, 0.019, and 0.039, respectively); however, the frequencies of the HLA-A*1101/LMP2-SSC pentamer did not differ significantly among patients at + 30, + 60, and + 90 days (p = 0.886). There was a significant difference in the frequency of the HLA-A*0201/BMLF1-GLC pentamer at + 60 days between patients with and without EBV-related diseases (p = 0.024). Patients with EBV-related diseases showed lower percentages of HLA-A*0201/BMLF1-GLC specific CD8⁺ T cells.

Conclusions

Haplo-HSCT recipients could generate EBV-specific CD8⁺ T cells within + 30 days after transplantation. The HLA-A*0201/BMLF1-GLC pentamer cell frequency at + 60 days may be a useful indicator for monitoring EBV-related diseases in patients after haplo-HSCT. Transfusion with EBV-CTLs within 60 days after haplo-HSCT may have prophylactic effects against EBV-related diseases.

HLA-A*11:01 is associated with levetiracetam-induced psychiatric adverse events

Levetiracetam (LEV) is effective for focal and generalized epilepsy and is used worldwide because of its relatively few drug interactions and favorable tolerability. However, some psychiatric adverse events (PAEs) have been reported, resulting in drug withdrawal. The pathophysiology of LEV-induced PAE has not yet been elucidated. In this study, we investigated the relationship between PAEs and human leukocyte antigen (HLA) genes. Eleven epilepsy patients, who developed PAEs after the administration of LEV and spontaneously improved after drug withdrawal, were enrolled retrospectively. Genomic DNA from the peripheral blood was extracted, and four-digit allele genotyping of HLA genes was performed. The genotype frequencies of HLA genes were compared to those of 80 patients in which LEV was well tolerated, as well as to 485 individuals from the general Korean population. The frequency of the HLA-A*1101 allele was significantly higher in the LEV-induced PAEs group compared to both the LEV-tolerant group (p = 0.021, OR 4.80, 95% CI 1.30-17.74) and the general Korean population (p = 0.015, OR 4.62, 95% CI 1.38-15.45). This study is the first attempt at investigating the relationship between the HLA system and LEV-induced PAE. The results of this study suggest that the HLA-A*1101 allele could be a risk factor for the development of PAEs.

CD40L-adjuvanted DNA vaccine carrying EBV-LMP2 antigen enhances anti-tumor effect in NPC transplantation tumor animal

CD40L, a costimulatory molecule for dendritic cells (DCs) and B cells, can serve as an adjuvant for enhancing the specific immune response induced by DNA vaccine carrying tumor-associated antigens. In this study, we investigated the potential of CD40L as an adjuvant to enhance the anti-tumor effect mediated by a DNA vaccine based on the Epstein-Barr virus-latent membrane protein 2 (EBV-LMP2) antigen. The plasmids capable of expressing the fusion protein EBV-LMP2-CD40L were constructed. Expression vector pVAX1 and plasmid expressing the individual antigen EBV-LMP2 were used as control groups. These plasmids were used to immunize female BALB/c mice (4-6 weeks old) at days 0, 7 and 14. The results suggest that immunization with DNA vaccines carrying fusion gene EBV-LMP2-CD40L can induce specific immunity more effectively than the plasmid expression individual antigen EBV-LMP2. In order to evaluate the anti-tumor effect of this DNA vaccine, we constructed a tumor bearing mouse model. After immunization, the tumor bearing mouse model, DNA vaccination with EBV-LMP2-CD40L plasmid significantly inhibited tumor growth in the tumor bearing mouse model and enhanced the tumor inhibition rate. This study demonstrated that encoding the EBV-LMP2 tumor antigen within an EBV-LMP2-CD40L DNA vaccine generates an effective antitumor response against EBV tumor, which may be a promising method to improve the antitumor immunity of DNA vaccine.

A novel Epstein-Barr virus-latent membrane protein-1-specific T-cell receptor for TCR gene therapy

BACKGROUND

Adoptive transfer of genetically engineered T-cells to express antigen-specific T-cell receptor (TCR) is a feasible and effective therapeutic approach for numerous types of cancers, including Epstein-Barr virus (EBV)-associated malignancies. Here, we describe a TCR gene transfer regimen to rapidly and reliably generate T-cells specific to EBV-encoded latent membrane protein-1 (LMP1), which is a potential target for T-cell-based immunotherapy.

METHODS

A novel TCR specific to LMP1 (LMP1-TCR) was isolated from HLA-A*0201 transgenic mice that were immunised with the minimal epitope LMP1₁₆₆ (TLLVDLLWL), and LMP1-TCR-transduced peripheral blood lymphocytes were evaluated for functional specificities.

RESULTS

Both human CD8 and CD4 T-cells expressing the LMP1-TCR provoked high levels of cytokine secretion and cytolytic activity towards peptide-pulsed and LMP1-expressing tumour cells. Notably, recognition of these T-cells to peptide-pulsed cells was maintained at low concentration of peptide, implying that the LMP1-TCR has high avidity. Infusion of these engineered T-cells revealed remarkable therapeutic effects and inhibition of tumour growth in a preclinical xenogeneic model. We observed explosive ex vivo proliferation of functional TCR-transduced T-cells with artificial antigen-presenting cells that express co-stimulatory molecules CD80 and 4-1BBL.

CONCLUSIONS

These data suggest that the novel TCR-targeting LMP1 might allow the potential design of T-cell-based immunotherapeutic strategies against EBV-positive malignancies.

Dual non-contiguous peptide occupancy of HLA class I evoke antiviral human CD8 T cell response and form neo-epitopes with self-antigens

Host CD8 T cell response to viral infections involves recognition of 8-10-mer peptides presented by MHC-I molecules. However, proteasomes generate predominantly 2-7-mer peptides, but the role of these peptides is largely unknown. Here, we show that single short peptides of <8-mer from Latent Membrane Protein 2 (LMP2) of Epstein Barr Virus (EBV) can bind HLA-A*11:01 and stimulate CD8+ cells. Surprisingly, two peptide fragments between 4-7-mer derived from LMP2(340-349) were able to complement each other, forming combination epitopes that can stimulate specific CD8+ T cell responses. Moreover, peptides from self-antigens can complement non-self peptides within the HLA binding cleft, forming neoepitopes. Solved structures of a tetra-complex comprising two peptides, HLA and β2-microglobulin revealed the free terminals of the two peptides to adopt an upward conformation directed towards the T cell receptor. Our results demonstrate a previously unknown mix-and-match combination of dual peptide occupancy in HLA that can generate vast combinatorial complexity.

Strategies to genetically engineer T cells for cancer immunotherapy

Immunotherapy is one of the most promising and innovative approaches to treat cancer, viral infections, and other immune-modulated diseases. Adoptive immunotherapy using gene-modified T cells is an exciting and rapidly evolving field. Exploiting knowledge of basic T cell biology and immune cell receptor function has fostered innovative approaches to modify immune cell function. Highly translatable clinical technologies have been developed to redirect T cell specificity by introducing designed receptors. The ability to engineer T cells to manifest desired phenotypes and functions is now a thrilling reality. In this review, we focus on outlining different varieties of genetically engineered T cells, their respective advantages and disadvantages as tools for immunotherapy, and their promise and drawbacks in the clinic.

Novel targets for natural killer/T-cell lymphoma immunotherapy

Extranodal natural killer/T-cell lymphoma, nasal type (NKTL) is a rare but highly aggressive Epstein-Barr virus-related malignancy, which mainly occurs in nasopharyngeal and nasal/paranasal areas. In addition to its high prevalence in Asian, Central American and South American populations, its incidence rate has been gradually increasing in Western countries. The current mainstay of treatment is a combination of multiple chemotherapies and irradiation. Although chemoradiotherapy can cure NKTL, it often causes severe and fatal adverse events. Because a growing body of evidence suggests that immunotherapy is effective against hematological malignancies, this treatment could provide an alternative to chemoradiotherapy for treatment of NKTL. In this review, we focus on how recent findings could be used to develop efficient immunotherapies against NKTL.