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Adoptive therapy with cytomegalovirus (CMV)-specific cytotoxic T lymphocytes (CMV-CTLs) has emerged as an effective method for CMV infection. However, the efficacy reportedly ranges from 50% to 90%, and factors affecting anti-CMV efficacy have not been established. We investigated the safety and efficacy of adoptive therapy with CMV-CTLs for CMV infection in 190 patients after haploidentical stem cell transplantation (haplo-SCT), and importantly, we analyzed the main factors affecting antiviral efficacy. The CMV peak titer decreased from 19 (range, 1.0-503.0) × 10

Influenza (flu) infection is a leading cause of respiratory diseases and death worldwide. Although seasonal flu vaccines are effective at reducing morbidity and mortality, such effects rely on the odds of successful prediction of the upcoming viral strains. Additional threats from emerging flu viruses that we cannot predict and avian flu viruses that can be directly transmitted to humans urge the strategic development of universal vaccination that can protect against flu viruses of different subtypes and across species. Annual flu vaccines elicit mainly humoral responses. Under circumstances when antibodies induced by vaccination fail to recognize and neutralize the emerging virus adequately, virus-specific cytotoxic T lymphocytes (CTLs) are the major contributors to the control of viral replication and elimination of infected cells. Our studies exploited the evolutionary conservation of influenza A nucleoprotein (NP) and the fact that NP-specific CTL responses pose a constant selecting pressure on functional CTL epitopes to screen for NP epitopes that are highly conserved among heterosubtypes but are subjected to positive selection historically. We identified a region on NP that is evolutionarily conserved and historically positively selected (NP

Bach2 codes for a transcriptional regulator exerting major influences on T cell-mediated immune regulation. Effector CTLs derived from in vitro activation of murine CD8+ T cells showed increased proliferative and cytolytic capacity in the absence of BACH2. Before activation, BACH2-deficient splenic CD8+ T cells had a higher abundance of memory and reduced abundance of naïve cells compared to wild-type. CTLs derived from central memory T cells were more potently cytotoxic than those derived from naïve T cells, but even within separated subsets, BACH2-deficiency conferred a cytotoxic advantage. Immunofluorescence and electron microscopy revealed larger granules in BACH2-deficient compared to wild-type CTLs, and proteomic analysis showed an increase in granule content, including perforin and granzymes. Thus, the enhanced cytotoxicity observed in effector CTLs lacking BACH2 arises not only from differences in their initial differentiation state but also inherent production of enlarged cytolytic granules. These results demonstrate how a single gene deletion can produce a CTL super-killer.

Vγ9Vδ2 T cells are attractive effector cells for immunotherapy with potent cytotoxic activity against a variety of malignant cells. However, the effect of Vγ9Vδ2 T cells on chemotherapy‐resistant acute myeloid leukemia (AML) blasts, especially highly refractory leukemia stem cells (LSCs) is still unknown. In this study, we investigated the effect of cytotoxicity of allogeneic Vγ9Vδ2 T cells on chemotherapy‐resistant AML cell lines, as well as on primary AML blasts and LSCs obtained from refractory AML patients. The results indicated that Vγ9Vδ2 T cells can efficiently kill drug‐resistant AML cell lines in vitro and in vivo, and the sensitivity of AML cells to Vγ9Vδ2 T cell–mediated cytotoxicity is not influenced by the sensitivity of AML cells to chemotherapy. We further found that Vγ9Vδ2 T cells exhibited a comparable effect of cytotoxicity against LSCs to primary AML blasts. More importantly, we revealed that the CD226–extracellular signal–regulatory kinase1/2 (ERK1/2)–lysosome‐associated membrane protein 1 (LAMP1) pathway is an important mechanism for Vγ9Vδ2 T cell–induced cytotoxicity against AML cells. First, Vγ9Vδ2 T cells recognized AML cells by receptor‐ligand interaction of CD226–Nectin‐2, which then induced ERK1/2 phosphorylation in Vγ9Vδ2 T cells. Finally, triggering the movement of lytic granules toward AML cells induced cytolysis of AML cells. The expression level of Nectin‐2 may be used as a novel marker to predict the susceptibility/resistance of AML cells to Vγ9Vδ2 T cell treatment., In this study, we indicated that Vγ9Vδ2 T cells can efficiently kill drug‐resistant acute myeloid leukemia (AML) cell lines in vitro and in vivo. We further found that Vγ9Vδ2 T cells exhibited a comparable effect of cytotoxicity against leukemia stem cells (LSCs) to primary AML blasts. More importantly, we revealed that Vγ9Vδ2 T cells induced cytotoxicity against AML cells via the CD226–extracellular signal–regulatory kinase1/2 (ERK1/2)–lysosome‐associated membrane protein 1 (LAMP1) pathway.

In a recent issue of The Journal of Pathology, a study by de Andrea, Ochoa, Villalba-Esparza et al demonstrated the presence of neutrophil extracellular traps (NETs) in a variety of human solid tumor types detected by multiplex immunofluorescence. In addition to NET identification and quantification, they found that there is individual heterogeneity in NET abundance in tumors and in circulation, and that NETs are positively associated with IL-8 and negatively associated with tumor-infiltrating CD8+ T cells. © 2021 The Pathological Society of Great Britain and Ireland. Published by John WileySons, Ltd.

CKLF‐like MARVEL transmembrane domain–containing protein 6 (CMTM6) maintains membrane PD‐L1 expression by controlling its endosomal recycling. However, in patients with hepatocellular carcinoma (HCC), the correlation among CMTM6, B7 family ligands, and CD8‐positive cytotoxic T lymphocytes (CTLs), and the molecular function of CMTM6 in HCC have not been established. We performed immunohistochemistry to evaluate the relationships among CMTM6 expression, clinicopathological factors, B7 family ligands expression, and CTL infiltration in HCC samples. Moreover, we established CMTM6‐knockout human HCC cell lines to evaluate the function of human CMTM6 in immune regulation and tumor viability. CMTM6 expression was positively associated with membrane B7 family ligands expression and CTL infiltration in HCC samples. High CMTM6 expression in HCC tissues was associated with the expression of the proliferation marker Ki‐67 and shorter recurrence‐free survival. In vitro analysis showed the downregulation of membrane B7 family ligands and proliferation potency in the CMTM6‐knockout human HCC cell line. High membrane CMTM6 expression was associated with tumor recurrence and proliferation via the regulation of membranous B7 family ligands expression. Thus, CMTM6 might be a biomarker to predict the risk of HCC recurrence and a therapeutic target to suppress tumor growth and increase CTL activity., CMTM6 expression was positively associated with B7 family ligand expression and cytotoxic T lymphocyte (CTL) infiltration in hepatocellular carcinoma (HCC) samples. The CMTM6‐knockout human HCC cell line showed the downregulation of membrane B7 family ligands expression and proliferation potency. High membrane CMTM6 expression was associated with tumor recurrence and proliferation via the regulation of membranous B7 family expression.

Regulatory T cells (Tregs) are indispensable for the maintenance of immunological self-tolerance and homeostasis. Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) is required for optimal Treg induction. Here, we reveal that human-induced Tregs (iTregs) lacking hnRNPA1 show reduced expression of the transcription factor FOXP3, increased ubiquitination level of FOXP3, and impaired suppressive abilities. Human naïve CD4 T cells with hnRNPA1 knockdown show a decreased Treg differentiation ratio. hnRNPA1 could interact with FOXP3 as well as with the E3 ligase Stub1. The phosphorylation at hnRNPA1 S199 could increase both interactions. The overexpression of FOXP3 in Tregs containing shhnRNPA1 could not recover the phenotype caused by hnRNPA1 knockdown. Therefore, there might be multiple essential pathways regulated by hnRNPA1 in Tregs. In conclusion, we present a new role of hnRNPA1 in promoting Treg function, indicating it as a promising target for tumor therapies.

Advances in immunotherapy with T cells armed with chimeric antigen receptors (CAR-Ts), opened up new horizons for the treatment of B-cell lymphoid malignancies. However, the lack of appropriate targetable antigens on the malignant myeloid cell deprives patients with refractory acute myeloid leukaemia of effective CAR-T therapies. Although non-engineered T cells targeting multiple leukaemia-associated antigens [i.e. leukaemia-specific T cells (Leuk-STs)] represent an alternative approach, the prerequisite challenge to obtain high numbers of dendritic cells (DCs) for large-scale Leuk-ST generation, limits their clinical implementation. We explored the feasibility of generating bivalent-Leuk-STs directed against Wilms tumour 1 (WT1) and preferentially expressed antigen in melanoma (PRAME) from umbilical cord blood units (UCBUs) disqualified for allogeneic haematopoietic stem cell transplantation. By repurposing non-transplantable UCBUs and optimising culture conditions, we consistently produced at clinical scale, both cluster of differentiation (CD)34+ cell-derived myeloid DCs and subsequently polyclonal bivalent-Leuk-STs. Those bivalent-Leuk-STs contained CD8+ and CD4+ T cell subsets predominantly of effector memory phenotype and presented high specificity and cytotoxicity against both WT1 and PRAME. In the present study, we provide a paradigm of circular economy by repurposing unusable UCBUs and a platform for future banking of Leuk-STs, as a 'third-party', 'off-the-shelf' T-cell product for the treatment of acute leukaemias.

Recurrent pregnancy loss (RPL) is one of the big challenges of normal pregnancy. Immune dysregulation has been proposed for the key underline mechanisms of RPL. However, the essential roles of T cells, especially γδ T cells, have not been defined.Decidua were obtained from normal pregnancy women or recurrent pregnancy loss patients and the surface molecules of γδ T cells in decidua were evaluated via flow cytometric analysis. The expression of PD-1 in clinical samples was analyzed by immunohistochemistry assay. The intracellular cytokines of decidual PD-1We demonstrated that PD-1 was significantly decreased on decidual tissue γδ T cells of patients with RPL, resulting in the enhanced cytotoxicity of γδ T cells against trophoblasts. We further elucidated an Erk-dependent TNF-α production mediates the γδ T cell cytotoxicity against the trophoblast cells. Finally, the reduced expression of PD-L1 in the villi tissues of patients with RPL might be the cause of the reduction of PD-1 on the tissue γδ T cells.Our study uncovers an important role of PD-1 expression on decidual γδ T cells in maintaining the normal pregnancy, and may provide a new strategy for immune therapy against RPL.

An approach of decorating bacteria with triple immune nanoactivators is reported to develop tumor-resident living immunotherapeutics. Under cytocompatible conditions, tumor-specific antigens and checkpoint blocking antibodies are simultaneously conjugated onto bacterial surface and then polydopamine nanoparticles are formed via in situ dopamine polymerization. In addition to serving as a linker, polydopamine with its photothermal effect can repolarize tumor-associated macrophages to a pro-inflammatory phenotype. The linked antigens promote the maturation of dendritic cells and generate tumor-specific immune responses, while the anchored antibodies block immune checkpoints and activate cytotoxic T lymphocytes. Decorated bacteria show spatiotemporal tumor retention and proliferation-dependent drug release, achieving potent antitumor effects in two antigen-overexpressing tumor models. This work provides a versatile platform to prepare multimodal and long-acting therapeutics for cancer immunotherapy.

The functional avidity (FA) of cytotoxic CD8 T cells impacts strongly on their functional capabilities and correlates with protection from infection and cancer. FA depends on TCR affinity, downstream signaling strength, and TCR affinity‐independent parameters of the immune synapse, such as costimulatory and inhibitory receptors. The functional impact of coreceptors on FA remains to be fully elucidated. Despite its importance, FA is infrequently assessed and incompletely understood. There is currently no consensus as to whether FA can be enhanced by optimized vaccine dose or boosting schedule. Recent findings suggest that FA is remarkably stable in vivo, possibly due to continued signaling modulation of critical receptors in the immune synapse. In this review, we provide an overview of the current knowledge and hypothesize that in vivo, codominant T cells constantly “equalize” their FA for similar function. We present a new model of constant FA regulation, and discuss practical implications for T‐cell‐based cancer immunotherapy., The functional avidity (FA) of CD8 T cells is stably maintained, and similar despite different TCR affinities of the codominant clonotypes. We hypothesize that continued adjustment of the net coreceptor signal strength (i) compensates for the differences in TCR affinity and (ii) acts to keep FA stable despite changing T‐cell activation stages.

Development of real-time non-invasive imaging probes to assess infiltration and activation of cytotoxic T cells (CTLs) is critical to predict the efficacy of cancer immunotherapy, which however remains challenging. Reported here is an activatable semiconducting polymer nanoprobe (SPNP) for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of a biomarker (granzyme B) associated with activation of CTLs. SPNP comprises a semiconducting polymer (SP) conjugated with a granzyme B cleavable and dye-labeled peptide as the side chain, both of which emit NIRF and PA signals. After systemic administration, SPNP passively targets the tumor and in situ reacts with granzyme B to release the dye-labeled peptide, leading to decreased NIRF and PA signals from the dye but unchanged signals from the polymer. Such ratiometric NIRF and PA signals of SPNP correlate well with the expression level of granzyme B and intratumoral population of CTLs. Thus, this study not only presents the first PA probes for in vivo imaging of immune activation but also provides a molecular design strategy that can be generalized for molecular imaging of other immune-related biomarkers. Ministry of Education (MOE) Nanyang Technological University K.P. thanks Nanyang Technological University (Start-Up grant:M4081627) and the Singapore Ministry of Education Academic Research Fund Tier 1 (2019-T1-002-045,RG125/19) and Academic Research Fund Tier 2 (MOE2018-T2-2-042) for the financial support. This work was also supported by the National Natural Science Foundation of China (81703031 and 81672937).

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the human gastrointestinal tract. In this study, we performed single‐cell RNA sequencing (RNA‐seq) on intra‐ and peri‐tumor tissues from GIST patients with the aim of discovering the heterogeneity of tumor cells in GIST and their interactions with other cells. We found four predominating cell types in GIST tumor tissue, including T cells, macrophages, tumor cells, and NK cells. Tumor cells could be clustered into two groups: one was highly proliferating and associated with high risk of metastasis, the other seemed “resting” and associated with low risk. Their clinical relevance and prognostic values were confirmed by RNA‐seq of 65 GIST samples. T cells were the largest cell type in our single‐cell data. Two groups of CD8+ effector memory (EM) cells were in the highest clonal expansion and performed the highest cytotoxicity but were also the most exhausted among all T cells. A group of macrophages were found polarized to possess both M1 and M2 signatures, and increased along with tumor progression. Cell‐to‐cell interaction analysis revealed that adipose endothelial cells had high interactions with tumor cells to facilitate their progression. Macrophages were at the center of the tumor microenvironment, recruiting immune cells to the tumor site and having most interactions with both tumor and nontumor cells. In conclusion, we obtained an overview of the GIST microenvironment and revealed the heterogeneity of each cell type and their relevance to risk classifications, which provided a novel theoretical basis for learning and curing GISTs., We performed single‐cell analysis on GISTs, obtained an overview of the GIST microenvironment, and revealed the heterogeneity of each cell type and their relevance to risk classifications according to bulk RNA sequencing cohorts. One subgroup of tumor cells was highly proliferating and associated with high risk of metastasis. A group of macrophages were found polarized to possess both M1 and M2 signatures, and increased along with tumor progression.

Objective Patients with epithelial ovarian cancer (EOC) typically present with late‐stage disease, posing a significant challenge to treatment. Although taxane and platinum‐based chemotherapy plus surgical debulking are initially effective, EOC is marked by frequent recurrence with resistant disease. Immunotherapy represents an appealing treatment paradigm given the ability of immune cells to engage metastatic sites and impede recurrence; however, response rates to checkpoint blockade in ovarian cancer have been disappointing. Here, we tested whether class I HDAC inhibition can promote anti‐tumor T cell responses in a spontaneous and nonspontaneous murine model of EOC. Methods We used the spontaneous Tg‐MISIIR‐Tag and nonspontaneous ID8 models of murine ovarian cancer to test this hypothesis. Whole tumor transcriptional changes were assessed using the nCounter PanCancer Mouse Immune Profiling Panel. Changes in select protein expression of regulatory and effector T cells were measured by flow cytometry. Results We found that treatment with the class I HDAC inhibitor entinostat upregulated pathways and genes associated with CD8 T cell cytotoxic function, while downregulating myeloid derived suppressor cell chemoattractants. Suppressive capacity of regulatory T cells within tumors and associated ascites was significantly reduced, reversing the CD8‐Treg ratio. Conclusions Our findings suggest class I HDAC inhibition can promote activation of intratumoral CD8 T cells, potentially by compromising suppressive networks within the EOC tumor microenvironment. In this manner, class I HDAC inhibition might render advanced‐stage EOC susceptible to immunotherapeutic treatment modalities., Expression of genes corresponding to CD8 T cell activation and effector function are upregulated following entinostat treatment. Class I HDAC inhibition also compromises the intratumoral suppressive network at multiple nodes in epithelial ovarian cancer. Accordingly, class I HDAC inhibition can be integrated into current treatment strategies to promote endogenous anti‐tumor immune responses and sensitize ovarian cancer to immunotherapy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can trigger a cytokine storm in the pulmonary tissue by releasing various types of mediators, leading to acute respiratory distress syndrome (ARDS). Increased neutrophil-to-lymphocyte ratio as well as CD4+ T lymphopenia is reported in cases with novel coronavirus disease (COVID-19), meanwhile lymphopenia is a significant finding in the majority of COVID-19 cases with severe phenotype. Moreover, excessive activation of monocyte/macrophage and cytokine storms is associated with the severity of the disease and the related complications in SARS-CoV-2 infection. Understanding the immune response dysregulation in COVID-19 is essential to develop more effective diagnostic, therapeutic, and prophylactic strategies in this pandemic. This article is protected by copyright. All rights reserved.

The programmed cell death‐1/programmed cell death‐ligand 1 (PD‐1/PD‐L1) pathway is involved in preventing immune system‐mediated destruction of malignant tumors including glioblastoma. However, the therapeutic influence of PD‐1/PD‐L1 inhibition alone in glioblastoma is limited. To develop effective combination therapy involving PD‐1/PD‐L1 inhibition, we used a non‐replicating virus‐derived vector, hemagglutinating virus of Japan‐envelope (HVJ‐E), to inhibit tumor cell PD‐L1 expression by delivering siRNA targeting PD‐L1. HVJ‐E is a promising vector for efficient delivery of enclosed substances to the target cells. Moreover, HVJ‐E provokes robust antitumoral immunity by activating natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), and by suppressing regulatory T lymphocytes (Treg). We hypothesized that we could efficiently deliver PD‐L1‐inhibiting siRNAs to tumor cells using HVJ‐E, and that synergistic activation of antitumoral immunity would occur due to the immunostimulating effects of HVJ‐E and PD‐1/PD‐L1 inhibition. We used artificially induced murine glioma stem‐like cells, TS, to create mouse (C57BL/6N) glioblastoma models. Intratumoral injection of HVJ‐E containing siRNA targeting PD‐L1 (siPDL1/HVJ‐E) suppressed the expression of tumor cell PD‐L1 and significantly suppressed tumor growth in subcutaneous models and prolonged overall survival in brain tumor models. Flow cytometric analyses of brain tumor models showed that the proportions of brain‐infiltrating CTL and NK cells were significantly increased after giving siPDL1/HVJ‐E; in contrast, the rate of Treg/CD4+ cells was significantly decreased in HVJ‐E‐treated tumors. CD8 depletion abrogated the therapeutic effect of siPDL1/HVJ‐E, indicating that CD8+ T lymphocytes mainly mediated this therapeutic effect. We believe that this non‐replicating immunovirotherapy may be a novel therapeutic alternative to treat patients with glioblastoma., HVJ‐E containing PD‐L1 siRNA significantly prolonged overall survival in mouse brain glioblastoma models. The therapeutic performance was mediated by antitumor immune responses via increased proportions of brain‐infiltrating CTL and a decreased rate of Treg among CD4+ T cells. This non‐replicating immunovirotherapy appears to show great promise as an attractive novel alternative to treat patients with glioblastoma.

Microglial cells are the main reservoir for HIV-1 within the brain and potential exists for negative immune checkpoint blockade therapies to purge this viral reservoir. Here, we investigated cytolytic responses of CD8(+) T lymphocytes against microglia loaded with peptide epitopes. Initially, flow cytometric analysis demonstrated efficient killing of HIV-1 p24 AI9 or YI9 peptide-loaded splenocytes in MHC-matched recipients. Cytolytic killing of microglia was first demonstrated using ovalbumin (OVA) as a model antigen for in vitro cytotoxic T lymphocyte (CTL) assays. Peptide-loaded primary microglia obtained from programmed death ligand (PD-L) 1 knockout (KO) animals showed significantly more killing than cells from wild-type (WT) animals when co-cultured with activated CD8(+) T-cells isolated from rAd5-OVA primed animals. Moreover, when peptide loaded-microglial cells from WT animals were treated with neutralizing α-PD-L1 Ab, significantly more killing was observed compared to either untreated or IgG isotype-treated cells. Most importantly, significantly increased in vivo killing of HIV-1 p24 YI9 peptide-loaded microglia from PD-L1 KO animals, as well as AI9 peptide-loaded BALB/c microglial cells treated with α-PD-L1, was observed within brains of rAd5-p24 primed-CNS boosted C57BL/6 or BALB/c mice, respectively. Finally, ex vivo responses of brain CD8(+) T-cells in response to AI9 stimulation showed significantly increased IFN-γ and IL-2 production when treated with α-PD-1 Abs. Greater proliferation of CD8+ T-cells from the brain was also observed following blockade. Taken together, these studies demonstrate that PD-L1 induction on microglia restrains CTL responses and indicate that immune checkpoint blockade targeting this pathway may be beneficial in clearing viral brain reservoirs.

In recent years, inhibitors of the BET bromodomain proteins, such as BRD4 inhibitors, have demonstrated robust antitumor activity. JQ-1, a representative small molecular BRD4 inhibitor, is also effective to block PD-1/PD-L1 signaling by significantly decreasing the PD-L1 expression on tumor cells. However, toxicity of BRD4 inhibitors on lymphoid and hematopoietic tissues limits their clinical usage. In this research, we designed and studied an immunogenic BRD4 inhibitor, SZU-119, by coupling JQ-1 with a TLR7 agonist, SZU-101. In vitro, SZU-119 stimulated the production of cytokines in mouse BMDCs and spleen lymphocytes, and inhibited the expression of PD-L1 in mouse B16 tumor cells. In vivo, SZU-119 suppressed the B16 tumor growth at both injected and uninjected sites, and prolonged the survival time of mice. SZU-119 elevated the number of total CD8+ and IFN-γ+ CD8+ T cells in spleens, with greater CTL cytotoxicity to B16 tumor cells. It was also observed that the infiltration of CD8+ T cells was increased in tumors at both local and distant sites, and the PD-L1 expression was decreased in tumor cells at the primary site. In conclusion, we have demonstrated that SZU-119 activated the innate immune cells, kept efficacy of PD-L1 blockade and abrogated immune toxicity, showing more potent antitumor effects than the simple mixture of SZU-101 and JQ-1 in a mouse melanoma model. Our work provides new insights for the development of anti-melanoma drugs that concurrently target innate and adaptive immunity.

Predictive biomarkers of response to immune checkpoint inhibitors (ICI) help to identify cancer patients who will benefit from immunotherapy. Protein kinase, DNA‐activated, catalytic subunit (PRKDC) is an important gene for DNA double‐strand break (DSB) repair and central T‐cell tolerance. We aimed to investigate the association between PRKDC mutations and tumor mutation burden (TMB), tumor microenvironment (TME), and response to ICI. Whole‐exome sequencing data of 4023 solid tumor samples from the Cancer Genome Atlas (TCGA) and panel‐based sequencing data of 3877 solid tumor samples from Geneplus‐Beijing, China, were used to analyze the TMB. The mRNA expression data of 3541 solid tumor samples from TCGA were used to explore the effect of PRKDC mutations on the TME. Four ICI‐treated cohorts were analyzed for verifying the correlation between PRKDC mutations and the response to ICI. In both the TCGA and Geneplus datasets, we found that the TMB in PRKDC mutation samples was significantly higher than in PRKDC wild‐type samples (P, Protein kinase, DNA‐activated, catalytic subunit (PRKDC) is a gene related to DNA damage response (DDR). Here, we found that PRKDC mutation often co‐exists with other DNA damage repair deficiencies and is associated with an increased tumor mutation burden, an inflamed tumor microenvironment, and a good response to immune checkpoint inhibitors.

A major challenge for the development of anticancer vaccines is the induction of a safe and effective immune response, particularly mediated by CD8+ T lymphocytes, in an adjuvant-free manner. In this respect, we present a simple strategy to improve the specific CD8+ T cell responses using KFE8 nanofibers bearing a Class I (Kb)-restricted peptide epitope (called E. nanofibers) without the use of adjuvant. We demonstrate that incorporation of Tat, a cell-penetrating peptide (CPP) of the HIV transactivator protein, into E. nanofibers remarkably enhanced tumor-specific CD8+ T cell responses. E. nanofibers containing 12.5% Tat peptide (E.Tat12.5 nanofiber) increased antigen cross-presentation by bone marrow-derived dendritic cells as compared with E. nanofibers, or E. nanofibers containing 25 or 50% the Tat peptide. Uptake of KFE8.Tat12.5 nanofibers by dendritic cells (DCs) was significantly increased compared with KFE8 nanofiber lacking Tat. Peritoneal and lymph node DCs of mice immunized with E.Tat12.5 nanofibers exhibited increased presentation of the H2kb-epitope (reminiscent for cross-presentation) compared with DCs obtained from E. nanofiber vaccinated mice. Tetrameric and intracellular cytokine staining revealed that vaccination with E.Tat12.5 triggered a robust and specific CD8+ T lymphocyte response, which was more pronounced than in mice vaccinated with E. nanofibers alone. Furthermore, E.Tat12.5 nanofibers were more potent than E. nanofiber to induce antitumor immune response and tumor-infiltrating IFN-γ CD8 T lymphocyte. In terms of cancer vaccine development, we propose that harnessing the nanofiber-based vaccine platform with incorporated Tat peptide could present a simple and promising strategy to induce highly effective antitumor immune response.

Lung cancer is the leading cause of cancer-related deaths worldwide. Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have often good clinical activity against non-small cell lung cancer (NSCLC) with activating EGFR mutations. Osimertinib, which is third-generation EGFR-TKI, provides clinical effect even on NSCLC harboring the threonine to methionine change at codon 790 of EGFR (EGFR T790M) mutation that cause TKI resistance. However, most NSCLC patients develop acquired resistance to Osimertinib within about one year, and 40% of these patients have the EGFR T790M and cysteine to serine change at codon 797 (C797S) mutations. Therefore, there is an urgent need for the development of novel treatment strategies for NSCLC patients with the EGFR T790M/C797S mutation. In this study, we novelty identified the EGFR T790M/C797S mutation-derived peptide (790-799) (MQLMPFGSLL) that binds the human leukocyte antigen (HLA)-A*02:01, and successfully established EGFR T790M/C797S-peptide-specific cytotoxic T lymphocyte (CTL) clones from human peripheral blood mononuclear cells (PBMCs) of HLA-A2 healthy donors. One established CTL clone demonstrated adequate cytotoxicity against T2 cells pulsed with the EGFR T790M/C797S peptide. This CTL clone also had high reactivity against cancer cells that expressed an endogenously EGFR T790M/C797S peptide using an interferon-γ (IFN-γ) enzyme-linked immunospot (ELISPOT) assay. In addition, we demonstrated using a mouse model that EGFR T790M/C797S peptide-specific CTLs were induced by EGFR T790M/C797S peptide vaccine in vivo. These findings suggest that an immunotherapy targeting a neoantigen derived from EGFR T790M/C797S mutation could be a useful novel therapeutic strategy for NSCLC patients with EGFR-TKI resistance, especially resistant to Osimertinib.

There is no established postoperative adjuvant therapy for hepatocellular carcinoma (HCC), and improvement of patient prognosis has been limited. We conducted long‐term monitoring of patients within a phase II trial that targeted a cancer antigen, glypican‐3 (GPC3), specifically expressed in HCC. We sought to determine if the GPC3 peptide vaccine was an effective adjuvant therapy by monitoring disease‐free survival and overall survival. We also tracked GPC3 immunohistochemical (IHC) staining, CTL induction, and postoperative plasma GPC3 for a patient group that was administered the vaccine (n = 35) and an unvaccinated patient group that underwent surgery only (n = 33). The 1‐y recurrence rate after surgery was reduced by approximately 15%, and the 5‐y and 8‐y survival rates were improved by approximately 10% and 30%, respectively, in the vaccinated group compared with the unvaccinated group. Patients who were positive for GPC3 IHC staining were more likely to have induced CTLs, and 60% survived beyond 5 y. Vaccine efficacy had a positive relationship with plasma concentration of GPC3; high concentrations increased the 5‐y survival rate to 75%. We thus expect GPC3 vaccination in patients with HCC, who are positive for GPC3 IHC staining and/or plasma GPC3 to induce CTL and have significantly improved long‐term prognosis., This phase II study demonstrated that postoperative adjuvant vaccination may reduce the 1‐y recurrence rate and prolong overall survival in patients who are positive for GPC3 IHC staining. The GPC3 peptide vaccine used induces specific CTLs and can be expected to improve patient prognosis.

The present study provides the first multiepitope vaccine construct using the 3CL hydrolase protein of SARS-CoV-2. The coronavirus 3CL hydrolase (Mpro) enzyme is essential for proteolytic maturation of the virus. This study was based on immunoinformatics and structural vaccinology strategies. The design of the multiepitope vaccine was built using helper T-cell and cytotoxic T-cell epitopes from the 3CL hydrolase protein along with an adjuvant to enhance immune response; these are joined to each other by short peptide linkers. The vaccine also carries potential B-cell linear epitope regions, B-cell discontinuous epitopes, and interferon-I³-inducing epitopes. Epitopes of the constructed multiepitope vaccine were found to be antigenic, nonallergic, nontoxic, and covering large human populations worldwide. The vaccine construct was modeled, validated, and refined by different programs to achieve a high-quality three-dimensional structure. The resulting high-quality model was applied for conformational B-cell epitope selection and docking analyses with toll-like receptor-3 for understanding the capability of the vaccine to elicit an immune response. In silico cloning and codon adaptation were also performed with the pET-19b plasmid vector. The designed multiepitope peptide vaccine may prompt the development of a vaccine to control SARS-CoV-2 infection.

Introduction Immunotherapy has shown promising results in non-small cell lung cancer (NSCLC), for which tumour-infiltrating cytotoxic (CD8+) T cells play a critical role. We investigated the utility of image analysis (IA) to quantify CD8+ T cells in a series of matched small biopsies and resections of NSCLC. Methods CD8 immunohistochemistry was performed on cell-blocks (CB), core needle biopsies (CNB) and corresponding resections from primary NSCLCs. Slides were digitised using an Aperio AT2 scanner (Leica) and annotated by whole slide image (WSI) or fields of view occupied by tissue spots (TS). Quantitative IA was performed with a customised Aperio algorithm (Leica). CD8 scores (number of T cells with 1-3+ staining/total area) were then compared. Results Forty-four cases with CB or CNB material and a corresponding resection were analysed. Average CD8 score was determined in CB (7.67 WSI, 77.67 TS) and/or CNB (47.35 WSI, 325.67 TS), and corresponding resections (190.35 WSI, 336.58 TS). CD8 score concordance was highest (78.6%) for CNBs using WSI annotation. Overall, small biopsies (CB or CNB) correlated with the resection in 71.4% cases using WSI and 63.3% cases using TS annotation. IA performed better for low CD8 scores. Conclusions These findings show that CD8 density in NSCLC can be quantified by IA in small biopsies and cell blocks, achieving the best concordance using WSI scores. Discrepancies were attributed to values near the cut-off and background detection of staining. These data warrant future studies with more cases and follow-up data to further investigate the clinical utility of IA for CD8 analysis in NSCLC.

Summary Excessive inflammatory immune responses during infections with Plasmodium parasites are responsible for severe complications such as cerebral malaria (CM) that can be studied experimentally in mice. Dendritic cells (DCs) activate cytotoxic CD8+ T‐cells and initiate immune responses against the parasites. Batf3 −/− mice lack a DC subset, which efficiently induces strong CD8 T‐cell responses by cross‐presentation of exogenous antigens. Here we show that Batf3 −/− mice infected with Plasmodium berghei ANKA (PbA) were protected from experimental CM (ECM), characterized by a stable blood−brain barrier (BBB) and significantly less infiltrated peripheral immune cells in the brain. Importantly, the absence of ECM in Batf3 −/− mice correlated with attenuated responses of cytotoxic T‐cells, as their parasite‐specific lytic activity as well as the production of interferon gamma and granzyme B were significantly decreased. Remarkably, spleens of ECM‐protected Batf3 −/− mice had elevated levels of regulatory immune cells and interleukin 10. Thus, protection from ECM in PbA‐infected Batf3 −/− mice was associated with the absence of strong CD8+ T‐cell activity and induction of immunoregulatory mediators and cells., Batf3‐deficient mice lack cross‐presenting dendritic cells that are crucial for CD8 T‐cell activation. Here we show that these mice are protected from experimental cerebral malaria upon infection with Plasmodium berghei ANKA. The protected mice showed a decreased cytotoxic response and signs of immune regulation.

Background Agglomeration of myeloid‐derived suppressor cells (MDSCs) in tumors impedes immunotherapeutic effects. Doxorubicin (DOX) is currently the most specific drug used for the selective removal of MDSCs. Here, we study the feasibility and mechanism of eliminating MDSCs by DOX to improve antigen‐specific cytotoxic T lymphocyte (CTL)‐killing neuroblastoma (NB) cells in vitro. Methods CTL and MDSC were prepared; then, CTLs, NB cells, MDSCs, and DOX were mixed and cultivated in different collocation patterns and divided into different groups. The levels of cluster of differentiation 3ζ chain (CD3ζ) and L‐selectin in CTL in different groups were detected. Thereafter, the killing rate of NB cells and secretion of interleukin‐2 and interferon‐γ were measured and compared. Results By real‐time polymerase chain reaction (PCR) and Western blot test respectively, the proliferation and killing effect of CTLs on NB cells were all inhibited by MDSC through downregulating CD3ζ (p = 0.002; p = 0.001) and L‐selectin (p = 0.006; p 0.05). Conclusions Targeted elimination of MDSCs by DOX can improve Ag‐specific CTL killing of NB cells in vitro by upregulating CD3ζ and L‐selectin. This study provides a novel method to enhance the immunotherapeutic effects of NB., High aggregation of myeloid‐derived suppressor cells (MDSCs) in the tumor microenvironment of neuroblastoma results in immunosuppression and affects its therapeutic effectiveness. Targeted elimination of MDSC by doxorubicin can improve antigen‐specific cytotoxic T lymphocyte killing neuroblastoma cells in vitro by upregulating the levels of cluster of differentiation 3ζ chain and L‐selectin. The present study provided a novel method to enhance immunotherapeutic effects for neuroblastoma.

Background Esophageal squamous cell carcinoma (ESCC) as the most prominent type of esophageal cancer (EC) in developing countries encompasses a substantial contribution of cancer‐related mortalities and morbidities. Cytotoxic T lymphocytes (CTLs) are the major subset of effector T cells against cancer. However, the microRNAs involved in the development and regulation of CTLs could be disrupted in cancers such as EC. Methods Here, we evaluated the population of IL‐10, TGF‐β, IFN‐γ, and IL‐17a‐producing CD3+CD8+ T cells, their association with the circulating levels of miR‐21 and miR‐29b, and their diagnostic and/or prognostic (after 160 weeks of follow‐up) utilities in 34 ESCC patients (12 newly diagnosed: ND, 24 under‐treatment: UT) and 34 matched healthy donors. Results The population of IL‐10 and TGF‐β‐producing CTLs (CD8+ Tregs) were considerably expanded, in addition to the overexpression of miR‐21 in both groups (ND and UT) of ESCC patients, while the frequency of Tc17 and CD8+ Treg cells increased only in UT patients. The expression means of TGF‐β and IL‐10 in CTLs were considered to be excellent biomarkers (1 ≥ area under the curve: AUC ≥0.9) in distinguishing ESCC patients and associated subgroups from healthy subjects. Moreover, the lower expressions of TGF‐β, IL‐17a, IL‐10, and IFN‐γ in CTLs were associated with ESCC better prognosis. Conclusions The association between the impaired function of CD3+ CD8+ T cell subsets and miR‐21 expression could be introduced as novel therapeutic targets and powerful diagnostic and prognostic markers for ESCC., Association between the expression of miR‐21 and miR‐29b with the impaired function of CD8+ T‐cell subsets could be introduced as novel therapeutic targets and powerful diagnostic and prognostic markers for ESCC.

Introduction Zoonotic cutaneous leishmaniasis (ZCL), due to infection by Leishmania (L). major, is characterized by polymorphic clinical manifestations which could be attributed to the host's immune response. In this study we investigated the involvement of cytotoxic cells on the outcome of the disease. Methods Expression of granzyme B (GrB), granulysine (Grly), and interferon (IFN)‐γ was evaluated within ZCL lesion specimens using the technique of real‐time quantitative polymerase chain reaction (RT‐qPCR). Immunohistochemical staining was performed using anti‐CD3, CD4, CD8, CD56, GrB, and IFN‐γ antibodies to identify the phenotype of GrB and IFN‐γ‐producing cells. Results GrB and Grly mRNA was detected within 75% and 80% of ZCL lesions, respectively. Statistical analysis demonstrated a significant correlation between levels of GrB and Grly. Interestingly, expression of these molecules correlates negatively with the lesion's age. The highest levels were measured in early lesions (E‐ZCL) (lesion age ≤1 month) comparing to late lesions (L‐ZCL) (lesion age >1 month). Otherwise, IFN‐γ mRNA was detected only within 56% and a positive correlation was found between levels of this cytokine and those of GrB. Immunohistochemical analysis showed that GrB is produced essentially by CD8+T cells whereas IFN‐γ is produced by both CD4+ and CD8+T cells. Conclusion Together our results demonstrate the presence of cytotoxic cells producing GrB and Grly within leishmaniasis cutaneous lesions.

Objective Human T cell lymphotropic virus 1 (HTLV‐1)‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive, neurological disease. Chronic activation of CD8+ T cells, as evidenced by increased spontaneous lymphoproliferation and HTLV‐1‐specific cytotoxic T cells, has been demonstrated in HAM/TSP patients. Since IL‐2 and IL‐15 stimulate memory CD8+ T cell activity, these cytokines have been implicated in the immunopathogenesis of HAM/TSP. In this phase I trial, we evaluated the safety, pharmacokinetics, and ability of Hu‐Mikβ1, a humanized monoclonal antibody directed toward the IL‐2/IL‐15 receptor β‐chain (IL‐2/IL‐15Rβ: CD122), to saturate CD122 and regulate abnormal immune responses in patients with HAM/TSP by inhibition of IL‐15 action. Methods Hu‐Mikβ1 was administered intravenously at doses of 0.5 mg/kg, 1.0 mg/kg, or 1.5 mg/kg in a total of nine HAM/TSP patients. Five doses of Hu‐Mikβ1 were administered at 3‐week intervals. The clinical response was evaluated using standardized scales. Viral and immunologic outcome measures were examined including HTLV‐1 proviral load, T cell phenotypic analysis and spontaneous lymphoproliferation in HAM/TSP patients. Results There was no significant toxicity associated with Hu‐Mikβ1 administration in HAM/TSP patients. Saturation of CD122 by Hu‐Mikβ1 was achieved in five out of nine HAM/TSP patients. Administration of Hu‐Mikβ1 was associated with inhibition of aberrant CD8+ T cell function including spontaneous lymphoproliferation and degranulation and IFN‐γ expression, especially in HAM/TSP patients that achieved CD122 saturation. Interpretation The treatment with Hu‐Mikβ1 had a number of immunological effects on HAM/TSP patients although no clinical efficacy was observed. We also did not see any dose‐related toxicity.

The majority of human CD8 cytotoxic T lymphocytes express αβ T-cell receptors that recognize peptide-MHC class I complexes. Considerable attention has been devoted to TCR β repertoires, but study of TCR α chains has been limited. To gain a better understanding of the features of CDR3α and CDR3β in paired samples, we comprehensively analyzed 776 unique paired αβ TCR CDR3 regions in this study. We found that (I) the CDR3 length among paired αβ TCRs had a fairly narrow distribution due to random assortment of CDR3 length in alpha and beta chains; (II) nucleotide deletions among CDR3 regions were positively correlated with insertions in both α and β TCRs; (III) the CDR3 loops of both α and β chains contained an abundance of charged/polar residues and the CDR3 base regions contained a conserved motif; and (IV) the occurrence of Gly was CDR3 length- and position-dependent in both chains, whereas the frequency of Ser at positions 106 and 107 was positively correlated with CDR3 length in TCR β. Overall, the amino acids in CDR3 loop regions were significantly different between TCR α and β, which suggests a distinct role for each chain in the recognition of antigen-MHC complexes. Here, we have provided detailed information on CDR3 in paired TCRs expressed on human CD8+ T cells and established the basis of a reference set for αβ TCR repertoires in healthy humans.

Foxp3-expressing regulatory T (Treg) cells, which are indispensable for preventing autoimmunity, also suppress effective tumor immunity. Treg cells abundantly infiltrate into tumor tissues, which is often associated with poor prognosis in cancer patients. Removal of Treg cells enhances anti-tumor immune responses but may also elicit autoimmunity. A key issue in devising Treg-targeting cancer immunotherapy is, therefore, how to specifically deplete Treg cells infiltrating into tumor tissues without affecting tumor-reactive effector T cells, while suppressing autoimmunity. This can be achieved by differentially controlling Treg and effector T cells by various ways. In this review, we discuss how tumor-infiltrating Foxp3+ Treg cells hamper effective anti-tumor immune responses especially in tumor tissues and how they can be specifically targeted for augmenting tumor immunity but not autoimmunity.

Alopecia areata (AA) is a relatively common disease, but no satisfactory treatment has yet been developed. Recently, research progress has been made in the pathogenesis of AA, revealing that autoreactive cytotoxic T cells are important and that the Janus kinase (JAK) pathway is involved. Therefore, the potential of JAK inhibitors as therapeutic agents for AA is attracting attention. Several single-arm clinical trials and retrospective studies demonstrated that oral JAK inhibitors are effective and tolerable treatments for moderate to severe AA. Although JAK inhibitors are emerging as an innovative treatment for AA, further placebo-controlled clinical trials are required to confirm their efficacy and long-term safety.

Adult T‐cell leukemia/lymphoma (ATL) is an aggressive lymphoproliferative disease caused by human T‐cell leukemia virus type 1 (HTLV‐1). Multi‐agent chemotherapy can reduce ATL cells but frequently allows relapses within a short period of time. Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) following chemotherapy is now a standard therapy for ATL in Japan as it can achieve long‐term remission in approximately one‐third of recipient ATL patients; however, it also has a risk of treatment‐related mortality. Allo‐HSCT often induces HTLV‐1 Tax‐specific cytotoxic T cells (CTL) as well as graft‐versus‐host (GVH) response in ATL patients. This observation led to development of a new therapeutic vaccine to activate Tax‐specific CTL, anticipating anti‐ATL effects without GVH response. The newly developed Tax‐DC vaccine consists of autologous dendritic cells pulsed with Tax peptides corresponding to CTL epitopes that have been identified in post‐allo‐HSCT ATL patients. In a pilot study of Tax‐DC therapy in three ATL patients after various initial therapies, two patients survived for more than 4 years after vaccination without severe adverse effects (UMIN000011423). The Tax‐DC vaccine is currently under phase I trial, showing a promising clinical outcome so far. These findings indicate the importance of patients’ own HTLV‐1‐specific T‐cell responses in maintaining remission and provide a new approach to anti‐ATL immunotherapy targeting Tax. Although Tax‐targeted vaccination is ineffective against Tax‐negative ATL cells, it can be a safe alternative maintenance therapy for Tax‐positive ATL and may be further applicable for treatment of indolent ATL or even prophylaxis of ATL development among HTLV‐1‐carriers.

Tumor immunotherapy is only effective in a fraction of patients due to a low response rate and severe side effects, and these challenges of immunotherapy in clinics can be addressed through induction of immunogenic cell death (ICD). ICD is elicited from many antitumor therapies to release danger associated molecular patterns (DAMPs) and tumor-associated antigens to facilitate maturation of dendritic cells (DCs) and infiltration of cytotoxic T lymphocytes (CTLs). The process can reverse the tumor immunosuppressive microenvironment to improve the sensitivity of immunotherapy. Nanostructure-based drug delivery systems (NDDSs) are explored to induce ICD by incorporating therapeutic molecules for chemotherapy, photosensitizers (PSs) for photodynamic therapy (PDT), photothermal conversion agents for photothermal therapy (PTT), and radiosensitizers for radiotherapy (RT). These NDDSs can release loaded agents at a right dose in the right place at the right time, resulting in greater effectiveness and lower toxicity. Immunotherapeutic agents can also be combined with these NDDSs to achieve the synergic antitumor effect in a multi-modality therapeutic approach. In this review, NDDSs are harnessed to load multiple agents to induce ICD by chemotherapy, PDT, PTT, and RT in combination of immunotherapy to promote the therapeutic effect and reduce side effects associated with cancer treatment.

Systemic immunosuppression mediated by tumor-derived exosomes is an important cause for the resistance of immune checkpoint blockade (ICB) therapy. Herein, self-adaptive platelet (PLT) pharmacytes are engineered to mediate cascaded delivery of exosome-inhibiting siRNA and anti-PD-L1 (aPDL1) toward synergized antitumor immunity. In the pharmacytes, polycationic nanocomplexes (NCs) assembled from Rab27 siRNA (siRab) and a membrane-penetrating polypeptide are encapsulated inside the open canalicular system of PLTs, and cytotoxic T lymphocytes (CTLs)-responsive aPDL1 nanogels (NGs) are covalently backpacked on the PLT surface. Upon systemic administration, the pharmacytes enable prolonged blood circulation and active accumulation to tumors, wherein PLTs are activated to liberate siRab NCs, which efficiently transfect tumor cells, silence Rab27a, and inhibit exosome secretion. The immunosuppression is thus relieved, leading to the activation, proliferation, and tumoral infiltration of cytotoxic T cells, which trigger latent aPDL1 release. As such, the competitive aPDL1 exhaustion by PD-L1-expressing exosomes is minimized to sensitize ICB. Synergistically, siRab and aPDL1 induce strong antitumor immunological response and memory against syngeneic murine melanoma. This study reports a bioinspired mechanism to resolve the blood circulation/cell internalization contradiction of polycationic siRNA delivery systems, and renders an enlightened approach for the spatiotemporal enhancement of antitumor immunity.

For efficacy of peptide vaccination immunotherapy for patients with cancer, endogenous expression of the target peptide/human leukocyte antigen (HLA) on cancer cells is required. However, it is difficult to evaluate the expression status of a peptide/HLA complex because of the lack of a soluble T‐cell receptor (TCR) that reacts with tumor‐associated antigen (TAA) with high avidity. In the present study, we developed two soluble TCR‐multimers that were each directed to TAA, survivin‐2B (SVN‐2B) and PBF in the context of HLA‐A24 (SVN‐2B TCR‐multimer and PBF TCR‐multimer, respectively), from CTL clones that were established from peptide‐vaccinated patients. Both TCR multimers could recognize cognate peptide‐pulsed antigen‐presenting cells, C1R‐A24 cells, in a CD8‐independent method. Moreover, the PBF TCR‐multimer successfully recognized a PBF peptide naturally presented on HLA‐A24+ PBF + osteosarcoma cells. Taken together, the results indicated that a TCR‐multimer might be useful for detection of a TAA‐derived peptide presented by HLA in patients receiving immunotherapy.

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is one of the important molecules that regulate the anti-melanoma T-cell response. Currently, there are some reports showing that CTLA-4 is expressed not only by T cells but also by various kinds of tumor cells, including melanoma cells. However, there is no report that shows the role of CTLA-4 expressed by melanoma cells in melanoma-specific cytotoxic T-lymphocyte (CTL) response. In this report, we confirmed substantial CTLA-4 expression and the localization of CTLA-4 in melanoma cell lines and tissues. Also, we examined its impact on melanoma-specific CTL in vitro, and found that CTLA-4 expressed by melanoma cells does not affect melanoma-specific CTL in the effector phase. Our findings suggest the importance of elucidating the role of CTLA-4 expressed by melanoma cells, particularly in anti-CTLA-4 antibody therapy.

Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma (pcAECyTCL) is a rare provisionally categorized cutaneous lymphoma characterized by an aggressive course. Its pathogenesis and molecular mechanisms are still unknown, and only two individual cases have so far been molecularly characterized. The aim of this study was to define the pattern of numerical chromosomal alterations in tumor samples taken from 20 patients with pcAECyTCL at the time of diagnosis by means of array-comparative genomic hybridization (a-CGH). a-CGH detected numerous genomic aberrations in all the patients and, putting these together as a whole, they affected all the chromosomes. However, no specific profile of recurrent copy number alterations (CNAs) was found. Most of the gains involved regions previously described in other aggressive cutaneous lymphomas such as 7q, 8q24.3, and 17q, whereas the most significant CNA was the loss of 9p21.3 (CDKN2A-CDKN2B), which has already been found in a variety of malignant tumors and is associated with aggressive cutaneous T-cell lymphomas. In brief, CGH analysis revealed a large number of CNAs with only few recurring regions that probably do not represent driving events. The genomic instability found in this aggressive variant of cutaneous lymphoma may therefore be a secondary event but, at the time of the diagnosis of pcAECyTCL, the genomic integrity of tumor cells is already compromised.

Despite the clinically proven efficacies of immune checkpoint blockades, including anti-cytotoxic T lymphocyte-associated protein 4 antibody (αCTLA-4), the low response rate and immune-related adverse events (irAEs) in cancer patients represent major drawbacks of the therapy. These drawbacks of αCTLA-4 therapy are mainly due to the suboptimal activation of tumor-specific cytotoxic T lymphocytes (CTLs) and the systemic nonspecific activation of T cells. To overcome such drawbacks, αCTLA-4 is delivered by dendritic cell-derived nanovesicles presenting tumor antigens (DCNV-TAs) that exclusively interact with tumor-specific T cells, leading to selective activation of tumor-specific CTLs. Compared to conventional αCTLA-4 therapy, treatment with αCTLA-4-conjugated DCNV-TAs significantly inhibits tumor growth and reduces irAEs in syngeneic tumor-bearing mice. This study demonstrates that the spatiotemporal presentation of both αCTLA-4 and tumor antigens enables selective activation of tumor-specific T cells and potentiates the antitumor efficacy of αCTLA-4 without inducing systemic irAEs.

Over the last 30 years, genetically engineered DNA has been tested as novel vaccination strategy against various diseases, including human immunodeficiency virus (HIV), hepatitis B, several parasites, and cancers. However, the clinical breakthrough of the technique is confined by the low transfection efficacy and immunogenicity of the employed vaccines. Therefore, carrier materials were designed to prevent the rapid degradation and systemic clearance of DNA in the body. In this context, biopolymers are a particularly promising DNA vaccine carrier platform due to their beneficial biochemical and physical characteristics, including biocompatibility, stability, and low toxicity. This article reviews the applications, fabrication, and modification of biopolymers as carrier medium for genetic vaccines.

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia commonly affecting children with frequent somatic mutations in MAPK pathway genes including BRAFV600E and MAP2K1. Some studies suggest that LCH cells can recruit and modulate inflammatory cells, which could provide reciprocal survival signals. To characterize the immune profile of infiltrating inflammatory cells, and to clarify their participation in LCH pathogenesis, a detailed immunohistochemical analysis was performed. Fifteen (10 children, 5 adults) LCH cases were assessed through macrophage (CD68 and CD163), mature dendritic cell (mDC; CD83 and CD208), regulatory T cell (Treg; CD4, CD25 and FOXP3) and cytotoxic lymphocyte (CL; CD56, CD57, perforin and granzyme B) immunomarkers. Moreover, lymphocytic and LCH markers were also analysed. All cases were S100, CD1a, CD207 and CD4-positive. Bcl-2 and cyclin D1 expression was observed in 13 of 15 cases. In the immune microenvironment, M2-polarized macrophages and Tregs were the predominant cell populations, followed by significantly (P < .005) smaller levels of mDCs and CLs. Additionally, the number of CD3 + cells was significantly higher than that of CD20 + cells. In the CD3 + cell population, there were a significantly higher number of CD4 + cells than CD8 + cells. While there were no differences when comparing the paediatric and adult populations, FOXP3 + cells were significantly higher in patients with multisystem involvement and treated with chemotherapy, than single-site cases and those without chemotherapy. Our results suggest that M2-polarized macrophages and Treg infiltration can promote LCH development and survival, probably through pro-tumoral, immunosuppressive and/or cytokine-mediated mechanisms. This work highlights the need for further exploration of immune-targeted therapy for LCH.

Both CD8(+) T cells and NK cells contribute to the immune response against the protozoan Leishmania parasite. Both are able to generate IFN‐γ and both display cytotoxic features. These features may enable them to not only contribute to parasite clearance but also to cause immune‐mediated pathology. This pathology is evident, for example, in the Leismania‐induced skin lesions found in patients with cutaneous leismaniasis (CL). Here we highlight new data demonstrating that CD8(+) T cells and NK cells in CL display a highly cytotoxic senescent phenotype, and that the senescent T cells play a major role in mediating skin pathology. This is the first demonstration that senescent CD8 T cells contribute to immunopathology in vivo.

Epstein-Barr virus (EBV) viremia and post-transplant lymphoproliferative disease (PTLD) are severe complications after hematopoietic stem cell transplantation (HSCT). A series of risk factors have been found to predict EBV viremia and PTLD, including the T-cell depletion, reduced intensity conditioning, and alternative donor. The rituximab pre-emptive therapy could improve PTLD prognosis significantly, but the trigger of initiating rituximab pre-emptive therapy has not been well established. Additionally, EBV-specific cytotoxic T cell (CTL) is a promising approach to treat EBV-PTLD.

CD4(+) Foxp3(+) regulatory T (Treg) cells can control both cellular and humoral immune responses; however, when and how Treg cells play a predominant role in regulating autoimmune disease remains elusive. To deplete Treg cells in vivo at given time‐points, we used a mouse strain, susceptible to glucose‐6‐phosphate isomerase peptide‐induced arthritis (GIA), in which the deletion of Treg cells can be controlled by diphtheria toxin treatment. By depleting Treg cells in the GIA mouse model, we found that a temporary lack of Treg cells at both priming and onset exaggerated disease development. Ablation of Treg cells led to the expansion of antigen‐specific CD4(+) T cells including granulocyte–macrophage colony‐stimulating factor, interferon‐γ and interleukin‐17‐producing T cells, and promoted both T‐cell and B‐cell epitope spreading, which perpetuated arthritis. Interestingly, specific depletion of cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4) on Treg cells only, was sufficient to protect mice from GIA, due to the expansion of CTLA‐4(−) Treg cells expressing alternative suppressive molecules. Collectively, our findings suggest that Treg cells, independently of CTLA‐4, act as the key driving force in controlling autoimmune arthritis development.

The cytotoxic synapse formed between cytotoxic T lymphocytes or natural killer cells expressing CD95L and target cells with CD95 on their surface is a key pathway for apoptosis induction by the immune system. Despite similarities with the immune synapse in antigen presenting cells, little is known about the role of the spatiotemporal organization of agonistic proteins/receptor interactions for CD95 signaling. Here, we have developed an artificial cytotoxic synapse to examine how mobility and geometry of an anti-CD95 agonistic antibody affect receptor aggregation and mobility, ie the first step of receptor activation. By measuring the distribution, diffusion coefficient, and fraction of immobile CD95 receptor in living cells, we show that at short times, the initial activation of CD95 occurs locally and is limited to the contact region of the cytotoxic synapse. This anisotropic activation of apoptotic signaling supports a role for confined interactions on the efficiency of signal transduction that may have implications for biomedical applications of extrinsic apoptosis induction. Fil: Sánchez, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina Fil: Murad, Fabronia. Universität Tübingen; Alemania Fil: Gülcüler Balta, Gülce S.. German Cancer Research Center; Alemania. Heidelberg University; Alemania Fil: Martin Villalba, Ana. German Cancer Research Center; Alemania Fil: García Sáez, Ana J.. Universität Tübingen; Alemania Fil: Carrer, Dolores Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina

Recently, bi-functional molecules that can redirect immune effectors to tumour cells have emerged as potentially robust mediators of tumour regression in clinical trials. Two modalities in particular, bi-specific antibodies for T-cell redirection and activation (BiTe) and immune-mobilizing monoclonal T-cell receptors against cancer (ImmTAC), are being evaluated in efficacy studies as 'off-the-shelf' reagents. Optimal therapy will require an understanding and means to address regulatory mechanisms of limiting efficacy. In light of this, we evaluated the impact of induced regulatory T (iTreg) cells on the efficacy of tumour cell killing redirected by ImmTAC and demonstrated down-regulation of T-cell proliferation and expression of CD25, CD107a, Granzyme B and Perforin by ImmTAC-redirected T cells. Significant recovery of ImmTAC potency, however, could be achieved when combined with an anti-programmed cell death protein 1 monoclonal antibody. Furthermore, we found that among lung cancer patients failing to respond to ImmTAC therapy, there was a significantly higher fraction of Treg cells in the peripheral blood mononuclear cells of lung cancer patients than in healthy donors. These results provide in vitro evidence for an iTreg cell-mediated immunosuppression of ImmTAC-redirected T-cell responses. Whilst immune checkpoint blockade can reverse the Treg cell suppression, it forms a rational basis for a combination of the blockade with ImmTAC in clinical trials.

In the first half of the 20th century, the major histocompatibility complex (MHC) of the laboratory mouse, the H-2 complex, was defined by a combination of serology and genetics. In the second half of the 20th century, its human counterpart, the human leukocyte antigen (HLA) complex was similarly defined and shown to mediate rejection of allogeneic kidney grafts. The clinical relevance of the transplantation antigens created the field of transplant immunology, which aimed to reduce graft rejection by HLA matching of transplant donors and recipients, and to use immunosuppressive drugs to prevent and treat rejection. Because tissue transplantation is not a natural phenomenon, the relevance of the MHC for immunology and immune defense against microbial pathogens was frequently questioned. In the 1970s, the general observation that cytotoxic T-cell responses to viral infection required recognition of both a viral antigen and a transplantation antigen argued for the immunological importance of the MHC. Proving this point was not achieved until close to the end of the 20th century. This required detailed biochemical and structural analysis of the transplantation antigens, the viral antigens, and the T-cell receptors that recognized them. This century of research culminated in 1996 with the three-dimensional crystallographic structure of the complex of these three components. In this complex is MAC, the very first HLA antigen to be detected and now more formally known as HLA-A*02:01.