Differences in CD44 Surface Expression Levels and Function Discriminates IL-17 and IFN-γ Producing Helper T Cells

Comparative analysis of changes in immune cell in the chicken spleen across different ages using flow cytometry

BACKGROUND

Concurrent emerging and reemerging avian infectious diseases cause multiple risk factors in poultry. A body amount studies attempted to understand pathogen-associated immunity in chickens. Recent research has made progress in identifying immune functions in chicken, there are still gaps in knowledge, especially regarding immune responses during infectious diseases. A deeper understanding in chicken immune system is critical for improving disease control strategies and vaccine development.

RESULTS

This study proposes analytical method for chicken splenocytes, enabling the tracking changes in T cells, monocytes, and B cells across three ages. Optimized lymphocyte-activating conditions were suggested using concanavalin A and chicken interleikin-2, which facilitate immune cell activation and proliferation. Next, splenocytes from embryonic day 18, day 5, and day 30 were compared using surface markers and flow cytometry analysis. We observed an increase in T cell subsets, including activated T cells (CD4+CD44+ and CD8+CD44+), and B cells, along with a reduced monocyte population after hatching. However, morphological changes and genetic expression of functional immune molecules were limited.

CONCLUSIONS

The present findings on chicken immune system development offer valuable insights into the avian immune system, including analytical methods and the phenotypic and functional changes in immune cells. Updated immune-boosting strategies during the early stages of life are crucial for developing preventive measures against major infectious diseases in the poultry industry.

Transient PU.1 low fetal progenitors generate lymphoid progeny that contribute to adult immunity

Hematopoietic stem cells and multipotential progenitors emerge in multiple, overlapping waves of fetal development. Some of these populations seed the bone marrow and sustain adult B- and T-cell development long-term after birth. However, others are present transiently, but whether they are vestigial or generate B and T cells that contribute to the adult immune system is not well understood. We now report that transient fetal progenitors distinguished by expression of low levels of the PU.1 transcription factor generated activated and memory T and B cells that colonized and were maintained in secondary lymphoid tissues. These included the small and large intestines, where they may contribute to the maintenance of gut homeostasis through at least middle age. At least some of the activated/memory cells may have been the progeny of B-1 and marginal zone B cells, as transient PU.1low fetal progenitors efficiently generated those populations. Taken together, our data demonstrate the potential of B- and T-cell progeny of transient PU.1low fetal progenitors to make an early and long-term contribution to the adult immune system.

Comprehensive proteomic analysis of the differential expression of 62 proteins following intracortical microelectrode implantation

Intracortical microelectrodes (IMEs) are devices designed to be implanted into the cerebral cortex for various neuroscience and neuro-engineering applications. A critical feature of IMEs is their ability to detect neural activity from individual neurons. Currently, IMEs are limited by chronic failure, largely considered to be caused by the prolonged neuroinflammatory response to the implanted devices. Over the past few years, the characterization of the neuroinflammatory response has grown in sophistication, with the most recent advances focusing on mRNA expression following IME implantation. While gene expression studies increase our broad understanding of the relationship between IMEs and cortical tissue, advanced proteomic techniques have not been reported. Proteomic evaluation is necessary to describe the diverse changes in protein expression specific to neuroinflammation, neurodegeneration, or tissue and cellular viability, which could lead to the further development of targeted intervention strategies designed to improve IME functionality. In this study, we have characterized the expression of 62 proteins within 180 μm of the IME implant site at 4-, 8-, and 16-weeks post-implantation. We identified potential targets for immunotherapies, as well as key pathways that contribute to neuronal dieback around the IME implant.

Longitudinal molecular profiling elucidates immunometabolism dynamics in breast cancer

Although metabolic reprogramming within tumor cells and tumor microenvironment (TME) is well described in breast cancer, little is known about how the interplay of immune state and cancer metabolism evolves during treatment. Here, we characterize the immunometabolic profiles of tumor tissue samples longitudinally collected from individuals with breast cancer before, during and after neoadjuvant chemotherapy (NAC) using proteomics, genomics and histopathology. We show that the pre-, on-treatment and dynamic changes of the immune state, tumor metabolic proteins and tumor cell gene expression profiling-based metabolic phenotype are associated with treatment response. Single-cell/nucleus RNA sequencing revealed distinct tumor and immune cell states in metabolism between cold and hot tumors. Potential drivers of NAC based on above analyses were validated in vitro. In summary, the study shows that the interaction of tumor-intrinsic metabolic states and TME is associated with treatment outcome, supporting the concept of targeting tumor metabolism for immunoregulation.

PI3K/mTOR inhibition induces tumour microenvironment remodelling and sensitises pS6high uterine leiomyosarcoma to PD-1 blockade

BACKGROUND

Uterine leiomyosarcomas (uLMS) are aggressive tumours with poor prognosis and limited treatment options. Although immune checkpoint blockade (ICB) has proven effective in some 'challenging-to-treat' cancers, clinical trials showed that uLMS do not respond to ICB. Emerging evidence suggests that aberrant PI3K/mTOR signalling can drive resistance to ICB. We therefore explored the relevance of the PI3K/mTOR pathway for ICB treatment in uLMS and explored pharmacological inhibition of this pathway to sensitise these tumours to ICB.

METHODS

We performed an integrated multiomics analysis based on TCGA data to explore the correlation between PI3K/mTOR dysregulation and immune infiltration in 101 LMS. We assessed response to PI3K/mTOR inhibitors in immunodeficient and humanized uLMS patient-derived xenografts (PDXs) by evaluating tumour microenvironment modulation using multiplex immunofluorescence. We explored response to single-agent and a combination of PI3K/mTOR inhibitors with PD-1 blockade in humanized uLMS PDXs. We mapped intratumoural dynamics using single-cell RNA/TCR sequencing of serially collected biopsies.

RESULTS

PI3K/mTOR over-activation (pS6high) associated with lymphocyte depletion and wound healing immune landscapes in (u)LMS, suggesting it contributes to immune evasion. In contrast, PI3K/mTOR inhibition induced profound tumour microenvironment remodelling in an ICB-resistant humanized uLMS PDX model, fostering adaptive anti-tumour immune responses. Indeed, PI3K/mTOR inhibition induced macrophage repolarisation towards an anti-tumourigenic phenotype and increased antigen presentation on dendritic and tumour cells, but also promoted infiltration of PD-1+ T cells displaying an exhausted phenotype. When combined with anti-PD-1, PI3K/mTOR inhibition led to partial or complete tumour responses, whereas no response to single-agent anti-PD-1 was observed. Combination therapy reinvigorated exhausted T cells and induced clonal hyper-expansion of a cytotoxic CD8+ T-cell population supported by a CD4+ Th1 niche.

CONCLUSIONS

Our findings indicate that aberrant PI3K/mTOR pathway activation contributes to immune escape in uLMS and provides a rationale for combining PI3K/mTOR inhibition with ICB for the treatment of this patient population.

Comprehensive Proteomic Analysis of the Differential Expression of 83 Proteins Following Intracortical Microelectrode Implantation

Intracortical microelectrodes (IMEs) are devices designed to be implanted into the cerebral cortex for various neuroscience and neuro-engineering applications. A critical feature of these devices is their ability to detect neural activity from individual neurons. Currently, IMEs are limited by chronic failure, largely considered to be caused by the prolonged neuroinflammatory response to the implanted devices. Over the decades, characterization of the neuroinflammatory response has grown in sophistication, with the most recent advances including advanced genomics and spatially resolved transcriptomics. While gene expression studies increase our broad understanding of the relationship between IMEs and cortical tissue, advanced proteomic techniques have not been reported. Proteomic evaluation is necessary to describe the diverse changes in protein expression specific to neuroinflammation, neurodegeneration, or tissue and cellular viability, which could lead to the development of more targeted intervention strategies designed to improve IME function. In this study, we have characterized the expression of 83 proteins within 180 μm of the IME implant site at 4-, 8-, and 16-weeks post-implantation. We identified potential targets for immunotherapies, as well as key pathways and functions that contribute to neuronal dieback around the IME implant.

Near-infrared photoimmunotherapy and anti-cancer immunity

The activation of the anti-cancer immune system is an important strategy to control cancer. A new form of cancer phototherapy, near-infrared photoimmunotherapy (NIR-PIT), was approved for clinical use in 2020 and uses IRDye® 700DX (IR700)-conjugated antibodies and NIR light. After irradiation with NIR light, the antibody-IR700 conjugate forms water-insoluble aggregations on the plasma membrane of target cells. This aggregation causes lethal damage to the plasma membrane, and effectively leads to immunogenic cell death (ICD). Subsequently, ICD activates anti-cancer immune cells such as dendritic cells and cytotoxic T cells. Combination therapy with immune-checkpoint blockade has synergistically improved the anti-cancer effects of NIR-PIT. Additionally, NIR-PIT can eliminate immunosuppressive immune cells in light-irradiated tumors by using specific antibodies against regulatory T cells and myeloid-derived suppressor cells. In addition to cancer-cell-targeted NIR-PIT, such immune-cell-targeted NIR-PIT has shown promising results by activating the anti-cancer immune system. Furthermore, NIR-PIT can be used to manipulate the tumor microenvironment by eliminating only targeted cells in the tumor, and thus it also can be used to gain insight into immunity in basic research.

Adaptive immune cells are necessary for SARS-CoV-2-induced pathology

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the ongoing global pandemic associated with morbidity and mortality in humans. Although disease severity correlates with immune dysregulation, the cellular mechanisms of inflammation and pathogenesis of COVID-19 remain relatively poorly understood. Here, we used mouse-adapted SARS-CoV-2 strain MA10 to investigate the role of adaptive immune cells in disease. We found that while infected wild-type mice lost ~10% weight by 3 to 4 days postinfection, rag-/- mice lacking B and T lymphocytes did not lose weight. Infected lungs at peak weight loss revealed lower pathology scores, fewer neutrophils, and lower interleukin-6 and tumor necrosis factor-α in rag-/- mice. Mice lacking αβ T cells also had less severe weight loss, but adoptive transfer of T and B cells into rag-/- mice did not significantly change the response. Collectively, these findings suggest that while adaptive immune cells are important for clearing SARS-CoV-2 infection, this comes at the expense of increased inflammation and pathology.

Social anxiety disorder-associated gut microbiota increases social fear

Social anxiety disorder (SAD) is a crippling psychiatric disorder characterized by intense fear or anxiety in social situations and their avoidance. However, the underlying biology of SAD is unclear and better treatments are needed. Recently, the gut microbiota has emerged as a key regulator of both brain and behaviour, especially those related to social function. Moreover, increasing data supports a role for immune function and oxytocin signalling in social responses. To investigate whether the gut microbiota plays a causal role in modulating behaviours relevant to SAD, we transplanted the microbiota from SAD patients, which was identified by 16S rRNA sequencing to be of a differential composition compared to healthy controls, to mice. Although the mice that received the SAD microbiota had normal behaviours across a battery of tests designed to assess depression and general anxiety-like behaviours, they had a specific heightened sensitivity to social fear, a model of SAD. This distinct heightened social fear response was coupled with changes in central and peripheral immune function and oxytocin expression in the bed nucleus of the stria terminalis. This work demonstrates an interkingdom basis for social fear responses and posits the microbiome as a potential therapeutic target for SAD.

Elucidating the neuroimmunology of traumatic brain injury: methodological approaches to unravel intercellular communication and function

The neuroimmunology of traumatic brain injury (TBI) has recently gained recognition as a crucial element in the secondary pathophysiological consequences that occur following neurotrauma. Both immune cells residing within the central nervous system (CNS) and those migrating from the periphery play significant roles in the development of secondary brain injury. However, the precise mechanisms governing communication between innate and adaptive immune cells remain incompletely understood, partly due to a limited utilization of relevant experimental models and techniques. Therefore, in this discussion, we outline current methodologies that can aid in the exploration of TBI neuroimmunology, with a particular emphasis on the interactions between resident neuroglial cells and recruited lymphocytes. These techniques encompass adoptive cell transfer, intra-CNS injection(s), selective cellular depletion, genetic manipulation, molecular neuroimaging, as well as in vitro co-culture systems and the utilization of organoid models. By incorporating key elements of both innate and adaptive immunity, these methods facilitate the examination of clinically relevant interactions. In addition to these preclinical approaches, we also detail an emerging avenue of research that seeks to leverage human biofluids. This approach enables the investigation of how resident and infiltrating immune cells modulate neuroglial responses after TBI. Considering the growing significance of neuroinflammation in TBI, the introduction and application of advanced methodologies will be pivotal in advancing translational research in this field.

Targeting PD-1/PD-L1 inhibits rejection in a heterotopic tracheal allograft model of lung transplantation

Immune checkpoint molecules such as programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) have revolutionized the field of lung cancer treatment. As part of our study, we examined the role of these proteins in acute rejection in a mouse model of heterotopic tracheal transplantation. Recipient mice were untreated (Allo group) or treated with anti-PD-L1 (aPDL1 group) or PD-L1 Fc recombinant protein (PD-L1 Fc group). A further group of C57BL/6 mice received isografts (Iso group). The occlusion rate was significantly higher in the Allo group than in the Iso group (p = 0.0075), and also higher in the aPD-L1 group (p = 0.0066) and lower in the PD-L1 Fc group (p = 0.030) than in the Allo group. PD-L1 Fc recombinant protein treatment significantly decreased interleukin-6 and interferon-γ levels and reduced the CD4+/CD8+ T cell ratio, without increasing PD-1 and T-cell immunoglobulin mucin 3 expression in CD4+ T cells. These data suggest that PD-L1 Fc recombinant protein decreases the levels of inflammatory cytokines and the proportion of CD4+ T cells without exhaustion. The PD-L1-mediated immune checkpoint mechanism was associated with rejection in the murine tracheal transplant model, suggesting a potential novel target for immunotherapy in lung transplantation.

Immunobiology of cancer stem cells and their immunoevasion mechanisms

Cancer stem cells (CSCs) defined as a small fraction of cells within malignancies have been isolated from tumors with different histological origins with stem related characteristics such as self-replicating potential, tumorigenesis, and therapy resistance. The dynamic communication between CSCs and tumor microenvironment particularly immune cells orchestrates their fate and plasticity as well as the patient outcome. According to recent evidence, it has been reported that they harness different immunological pathways to escape immunosurveillance and express aberrantly immunomodulatory agents or decreased levels of factors forming antigen presenting machinery (APM), subsequently followed by impaired antigen presentation and suppressed immune detection. As effective therapies are expected to be able to eradicate CSCs, mechanistic understanding of such interactions can provide insights into causes of therapy failure particularly in immunotherapy. Also, it can contribute to enhance the practical interventions against CSCs and their immunomodulatory features resulting in CSCs eradication and improving patient clinical outcome. The aim of this review is to explain the present knowledge regarding the immunobiology of CSCs and the immunoevasion mechanisms they use.

Graft conditioning with fluticasone propionate reduces graft-versus-host disease upon allogeneic hematopoietic cell transplantation in mice

Hematopoietic cell transplantation (HCT) treats many blood conditions but remains underused due to complications such as graft-versus-host disease (GvHD). In GvHD, donor immune cells attack the patient, requiring powerful immunosuppressive drugs like glucocorticoids (GCs) to prevent death. In this study, we tested the hypothesis that donor cell conditioning with the glucocorticoid fluticasone propionate (FLU) prior to transplantation could increase hematopoietic stem cell (HSC) engraftment and reduce GvHD. Murine HSCs treated with FLU had increased HSC engraftment and reduced severity and incidence of GvHD after transplantation into allogeneic hosts. While most T cells died upon FLU treatment, donor T cells repopulated in the hosts and appeared less inflammatory and alloreactive. Regulatory T cells (Tregs) are immunomodulatory and survived FLU treatment, resulting in an increased ratio of Tregs to conventional T cells. Our results implicate an important role for Tregs in maintaining allogeneic tolerance in FLU-treated grafts and suggest a therapeutic strategy of pre-treating donor cells (and not the patients directly) with GCs to simultaneously enhance engraftment and reduce GvHD upon allogeneic HCT.

T memory stem cell characteristics in autoimmune diseases and their promising therapeutic values

Memory T cells are conventionally subdivided into T central memory (T_CM) and T effector memory (T_EM) cells. However, a new subset of memory T cells named T memory stem cell (T_SCM) cells has been recognized that possesses capabilities of both T_CM and T_EM cells including lymphoid homing and performing effector roles through secretion of cytokines such as interleukin-2 (IL-2) and interferon-gamma (IFN-γ). The T_SCM subset has some biological properties including stemness, antigen independency, high proliferative potential, signaling pathway and lipid metabolism. On the other hand, memory T cells are considered one of the principal culprits in the pathogenesis of autoimmune diseases. T_SCM cells are responsible for developing long-term defensive immunity against different foreign antigens, alongside tumor-associated antigens, which mainly derive from self-antigens. Hence, antigen-specific T_SCM cells can produce antitumor responses that are potentially able to trigger autoimmune activities. Therefore, we reviewed recent evidence on T_SCM cell functions in autoimmune disorders including type 1 diabetes, systemic lupus erythematosus, rheumatoid arthritis, acquired aplastic anemia, immune thrombocytopenia, and autoimmune uveitis. We also introduced T_SCM cell lineage as an innovative prognostic biomarker and a promising therapeutic target in autoimmune settings.

A potential platform of combining sialic acid derivative-modified paclitaxel cationic liposomes with antibody-drug conjugates inspires robust tumor-specific immunological memory in solid tumors

The recent approvals for antibody-drug conjugates (ADCs) in multiple malignancies in the past few years have fueled the ongoing development of this class of drug. However, the limitation of ADCs is selectivity toward cancer cells especially overexpressing the antigen of interest. To broaden the anti-cancer spectrum of ADCs, combinatorial strategies of ADCs with chemotherapy have become a central focus of the current preclinical and clinical research. Here, we used the microtubule stabilizer paclitaxel and enfortumab vedotin-ejfv (EV), an ADC carrying the microtubule inhibitor payload monomethyl auristatin E (MMAE), for co-administration under the consideration of their mechanism of action associated with microtubules. We designed a sialic acid-cholesterol (SA-CH) conjugate-modified cationic liposome platform loaded with PTX (PTX-SAL) for efficiently targeting tumor-associated immune cells. Compared with monotherapy, PTX-SAL-mediated combination therapy with ADCs significantly inhibited S180 tumor growth in mice, with complete tumor regression occurring. The formation of a durable tumor-specific immunological memory response in mice that experienced complete tumor regression was assessed by secondary tumor cell rechallenge, and the production of memory T cells in the spleen was detected as related to the increased CD4⁺T memory cells and the enhanced serum IFN-γ. All our preliminary results throw light on the tremendous application potential for the application of this combination therapy regimen capable of mounting a durable immune response and stimulating a robust T cell-mediated tumor-specific immunological memory.

TCR-signals downstream adversely correlate with the survival signals of memory CD8+ T cells under homeostasis

The significance of self-peptide-MHC-I/TCR (SMT) interaction in the survival of CD8⁺ T cells during naïve- and developmental-stages is well documented. However, the same for the memory stage is contentious. Previous studies have attempted to address the issue using MHC-I or TCR deficient systems, but inconsistent findings with memory CD8⁺ T cells of different TCR specificities have complicated the interpretation. Differential presence and/or processing of TCR-signals downstream in memory CD8⁺ T cells of different TCR specificities could be thought of as a reason. In this study, we examined the TCR-signals downstream in memory CD8⁺ T cells and compared them to the presence of survival-related signals (Annexin-V, Bcl-2, and Ki-67). We categorically tracked foreign antigen-experienced memory CD8⁺ T (TM) cells generated after Plasmodium pre-erythrocytic-stage malaria infection in C57BL/6 mice. Interestingly, we found that memory CD8⁺ T cells had more TCR-signals downstream than naive cells. We reasoned and attributed the increased expression of cell adhesion molecules to the enhanced TCR-signaling. TCR-signals downstream correlate more closely with survival signals in naive CD8⁺ T cells than with death signals in TM cells. Further investigation using antigen-specific CD8⁺ T cells and diverse infection systems would aid in conceptualizing the findings.

Preparation of chitosan nanoparticle containing recombinant CD44v antigen and evaluation of its immunization capacity against breast cancer in BALB/c mice

OBJECTIVE(S)

Breast tumors show heterogeneity containing cancer stem cells as a small subpopulation of a tumor mass. CD44 as a cancer stem cells antigen is abnormally expressed by carcinomas of epithelial origin. Also, overexpression of CD44 variable isoforms (CD44v) is associated with malignancy in breast cancer. In the present research, our objective was to evaluate the immunogenicity of prepared nanoparticles containing a novel recombinant CD44v (rCD44v) protein in the mouse model.

MATERIALS AND METHODS

CD44 gene was expressed in E. coli BL21 DE3 using the pET28a-CD44 vector. The expressed rCD44v protein was purified, encapsulated into the chitosan nanoparticles, and administered to BALB/c mice. ELISA was used to evaluate the immunoglobulin levels of immunized animals. For challenge experiment, 2 × 10⁶ 4T1-CD44 tumor cells were injected subcutaneously in mice, and tumor size, necrosis, and metastases were measured. Finally, cell proliferation assay, cytokines assay, and neutralization assay of the mouse anti-rCD44v on the human breast cancer cell line were examined.

RESULTS

The measured size of chitosan-rCD44v nanoparticles was 146.5 nm. Recombinant CD44v encapsulated by chitosan nanoparticles increases immunological responses via the adjuvant nature of chitosan nanoparticles. In the immunized mice, IgG and IgA titers were significantly increased. Tumor growth in injection and nano-injection test groups compared with the mice control groups displayed a significant reduction (P < 0.05). A high amount of splenocytes secreting IFNγ and IL-17 was seen in immunized mice with rCD44v (P < 0.05). Furthermore, a smaller size of lung metastases compared to the control mice groups was detected.

CONCLUSION

The encapsulated rCD44v within the chitosan nanoparticles induced a significant immune response in mice and can establish significant protection against breast cancer. Therefore, it can be considered a vaccine candidate for breast cancer therapeutic modalities.

Expansion of T memory stem cells with superior anti-tumor immunity by Urolithin A-induced mitophagy

T memory stem cells (T_SCM) display increased self-renewal and prolonged survival capabilities, thus preventing T cell exhaustion and promoting effective anti-tumor T cell responses. T_SCM cells can be expanded by Urolithin A (UA), which is produced by the commensal gut microbiome from foods rich in ellagitannins and is known to improve mitochondrial health. Oral UA administration to tumor-bearing mice conferred strong anti-tumor CD8⁺ T cell immunity, whereas ex vivo UA pre-treated T cells displayed improved anti-tumor function upon adoptive cell transfer. UA-induced T_SCM formation depended on Pink1-mediated mitophagy triggering cytosolic release of the mitochondrial phosphatase Pgam5. Cytosolic Pgam5 dephosphorylated β-catenin, which drove Wnt signaling and compensatory mitochondrial biogenesis. Collectively, we unravel a critical signaling pathway linking mitophagy to T_SCM formation and suggest that the well-tolerated metabolic compound UA represents an attractive option to improve immune therapy.

A Distinctive γδ T Cell Repertoire in NOD Mice Weakens Immune Regulation and Favors Diabetic Disease

Previous studies in mice and humans suggesting that γδ T cells play a role in the development of type 1 diabetes have been inconsistent and contradictory. We attempted to resolve this for the type 1 diabetes-prone NOD mice by characterizing their γδ T cell populations, and by investigating the functional contributions of particular γδ T cells subsets, using Vγ-gene targeted NOD mice. We found evidence that NOD Vγ4+ γδ T cells inhibit the development of diabetes, and that the process by which they do so involves IL-17 production and/or promotion of regulatory CD4+ αβ T cells (Tregs) in the pancreatic lymph nodes. In contrast, the NOD Vγ1+ cells promote diabetes development. Enhanced Vγ1+ cell numbers in NOD mice, in particular those biased to produce IFNγ, appear to favor diabetic disease. Within NOD mice deficient in particular γδ T cell subsets, we noted that changes in the abundance of non-targeted T cell types also occurred, which varied depending upon the γδ T cells that were missing. Our results indicate that while certain γδ T cell subsets inhibit the development of spontaneous type 1 diabetes, others exacerbate it, and they may do so via mechanisms that include altering the levels of other T cells.

Single-cell atlas unveils cellular heterogeneity and novel markers in human neonatal and adult intervertebral discs

The origin, composition, distribution, and function of cells in the human intervertebral disc (IVD) have not been fully understood. Here, cell atlases of both human neonatal and adult IVDs have been generated and further assessed by gene ontology pathway enrichment, pseudo-time trajectory, histology, and immunofluorescence. Comparison of cell atlases revealed the presence of two subpopulations of notochordal cells (NCs) and their associated markers in both the neonatal and adult IVDs. Developmental trajectories predicted 7 different cell states that describe the developmental process from neonatal to adult cells in IVD and analyzed the NC’s role in the IVD development. A high heterogeneity and gradual transition of annulus fibrosus cells (AFCs) in the neonatal IVD was detected and their potential relevance in IVD development assessed. Collectively, comparing single-cell atlases between neonatal and adult IVDs delineates the landscape of IVD cell biology and may help discover novel therapeutic targets for IVD degeneration.

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Compared scRNA-seq between human neonatal and adult IVD

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Identified two notochordal cell populations in adults and their novel markers

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Notochordal cells preserved their identity and functions into adulthood

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Unveiled heterogeneity of nucleus pulposus and annulus fibrosus cells in human IVD

Current Strategies for the Treatment of Hepatocellular Carcinoma by Modulating the Tumor Microenvironment via Nano-Delivery Systems: A Review

Liver cancer remains a global health challenge with a projected incidence of over one million cases by 2025. Hepatocellular carcinoma (HCC) is a common primary liver cancer, accounting for about 90% of all liver cancer cases. The tumor microenvironment (TME) is the internal and external environment for tumor development, which plays an important role in tumorigenesis, immune escape and treatment resistance. Knowing that TME is a unique setting for HCC tumorigenesis, exploration of strategies to modulate TME has attracted increasing attention. Among them, the use of nano-delivery systems to deliver therapeutic agents to regulate TME components has shown great potential. TME-modulating nanoparticles have the advantages of protecting therapeutic agents from degradation, enhancing the ability of targeting HCC and reducing systemic toxicity. In this article, we summarize the TME components associated with HCC, including cancer-associated fibroblasts (CAFs), extracellular matrix (ECM), endothelial cells and immune cells, discuss their impact on the HCC progression, and highlight recent studies on nano-delivery systems that modulate these components. Finally, we also discuss opportunities and challenges in this field.

Nanoparticle-delivered TLR4 and RIG-I agonists enhance immune response to SARS-CoV-2 subunit vaccine

Despite recent success in vaccinating populations against SARS-CoV-2, concerns about immunity duration, continued efficacy against emerging variants, protection from infection and transmission, and worldwide vaccine availability, remain. Although mRNA, pDNA, and viral-vector based vaccines are being administered, no protein subunit-based SARS-CoV-2 vaccine is approved. Molecular adjuvants targeting pathogen-recognition receptors (PRRs) on antigen-presenting cells (APCs) could improve and broaden the efficacy and durability of vaccine responses. Native SARS-CoV-2 infection stimulate various PRRs, including toll-like receptors (TLRs) and retinoic-acid-inducible gene I-like receptors (RIG-I). We hypothesized that targeting the same PRRs using adjuvants on nanoparticles along with a stabilized spike (S) protein antigen could provide broad and efficient immune responses. Formulations targeting TLR4 (MPLA), TLR7/8 (R848), TLR9 (CpG), and RIG-I (PUUC) delivered on degradable polymer-nanoparticles (NPs) were combined with the S1 subunit of S protein and assessed in vitro with isogeneic mixed lymphocyte reactions (iso-MLRs). For in vivo studies, the adjuvanted nanoparticles were combined with stabilized S protein and assessed using intranasal and intramuscular prime-boost vaccination models in mice. Combination NP-adjuvants targeting both TLR and RIG-I (MPLA+PUUC, CpG+PUUC, or R848+PUUC) differentially increased proinflammatory cytokine secretion (IL-1β, IL-12p70, IL-27, IFN-β) by APCs cultured in vitro, and induced differential T cell proliferation. When delivered intranasally, MPLA+PUUC NPs enhanced local CD4+CD44+ activated memory T cell responses while MPLA NPs increased anti-S-protein-specific IgG and IgA in the lung. Following intramuscular delivery, PUUC-carrying NPs induced strong humoral immune responses, characterized by increases in anti-S-protein IgG and neutralizing antibody titers and germinal center B cell populations (GL7+ and BCL6+ B cells). MPLA+PUUC NPs further boosted S-protein-neutralizing antibody titers and T follicular helper cell populations in draining lymph nodes. These results suggest that SARS-CoV-2-mimicking adjuvants and subunit vaccines could lead to robust and unique route-specific adaptive immune responses and may provide additional tools against the pandemic.

Modulating donor mitochondrial fusion/fission delivers immunoprotective effects in cardiac transplantation

Early insults associated with cardiac transplantation increase the immunogenicity of donor microvascular endothelial cells (ECs), which interact with recipient alloreactive memory T cells and promote responses leading to allograft rejection. Thus, modulating EC immunogenicity could potentially alter T cell responses. Recent studies have shown modulating mitochondrial fusion/fission alters immune cell phenotype. Here, we assess whether modulating mitochondrial fusion/fission reduces EC immunogenicity and alters EC-T cell interactions. By knocking down DRP1, a mitochondrial fission protein, or by using the small molecules M1, a fusion promoter, and Mdivi1, a fission inhibitor, we demonstrate that promoting mitochondrial fusion reduced EC immunogenicity to allogeneic CD8⁺ T cells, shown by decreased T cell cytotoxic proteins, decreased EC VCAM-1, MHC-I expression, and increased PD-L1 expression. Co-cultured T cells also displayed decreased memory frequencies and Ki-67 proliferative index. For in vivo significance, we used a novel murine brain-dead donor transplant model. Balb/c hearts pretreated with M1/Mdivi1 after brain-death induction were heterotopically transplanted into C57BL/6 recipients. We demonstrate that, in line with our in vitro studies, M1/Mdivi1 pretreatment protected cardiac allografts from injury, decreased infiltrating T cell production of cytotoxic proteins, and prolonged allograft survival. Collectively, our data show promoting mitochondrial fusion in donor ECs mitigates recipient T cell responses and leads to significantly improved cardiac transplant survival.

Cladribine Alters Immune Cell Surface Molecules for Adhesion and Costimulation: Further Insights to the Mode of Action in Multiple Sclerosis

Cladribine (CLAD) is a deoxyadenosine analogue prodrug which is given in multiple sclerosis (MS) as two short oral treatment courses 12 months apart. Reconstitution of adaptive immune function following selective immune cell depletion is the presumed mode of action. In this exploratory study, we investigated the impact of CLAD tablets on immune cell surface molecules for adhesion (CAMs) and costimulation (CoSs) in people with MS (pwMS). We studied 18 pwMS who started treatment with CLAD and 10 healthy controls (HCs). Peripheral blood mononuclear cells were collected at baseline and every 3 months throughout a 24-month period. We analysed ICAM-1, LFA-1, CD28, HLADR, CD154, CD44, VLA-4 (CD49d/CD29), PSGL-1 and PD-1 with regard to their expression on B and T cells (T helper (Th) and cytotoxic T cells (cT)) and surface density (mean fluorescence intensity, MFI) by flow cytometry. The targeted analysis of CAM and CoS on the surface of immune cells in pwMS revealed a higher percentage of ICAM-1 (B cells, Th, cT), LFA-1 (B cells, cT), HLADR (B cells, cT), CD28 (cT) and CD154 (Th). In pwMS, we found lower frequencies of Th and cT cells expressing PSGL-1 and B cells for the inhibitory signal PD-1, whereas the surface expression of LFA-1 on cT and of HLADR on B cells was denser. Twenty-four months after the first CLAD cycle, the frequencies of B cells expressing CD44, CD29 and CD49d were lower compared with the baseline, together with decreased densities of ICAM-1, CD44 and HLADR. The rate of CD154 expressing Th cells dropped at 12 months. For cT, no changes were seen for frequency or density. Immune reconstitution by oral CLAD was associated with modification of the pro-migratory and -inflammatory surface patterns of CAMs and CoSs in immune cell subsets. This observation pertains primarily to B cells, which are key cells underlying MS pathogenesis.

An Engineered Prussian Blue Nanoparticles-based Nanoimmunotherapy Elicits Robust and Persistent Immunological Memory in a TH-MYCN Neuroblastoma Model

A combination therapy using Prussian blue nanoparticles (PBNP) as photothermal therapy (PTT) agents coated with CpG oligodeoxynucleotides, an immunologic adjuvant, as a nanoimmunotherapy (CpG-PBNP-PTT) for neuroblastoma (NB) is described. NB driven by MYCN amplification confers high risk and correlates with a dismal prognosis, accounting for the majority of NB-related mortality. The efficacy of the CpG-PBNP-PTT nanoimmunotherapy in a clinically relevant, TH-MYCN murine NB model (9464D) overexpressing MYCN is tested. When administered to 9464D NB cells in vitro, CpG-PBNP-PTT triggers thermal dose-dependent immunogenic cell death and tumor cell priming for immune recognition in vitro, measured by the expression of specific costimulatory and antigen-presenting molecules. In vivo, intratumorally administered CpG-PBNP-PTT generates complete tumor regression and significantly higher long-term survival compared to controls. Furthermore, CpG-PBNP-PTT-treated mice reject tumor rechallenge. Ex vivo studies confirm these therapeutic responses result from the generation of robust T cell-mediated immunological memory. Consequently, in a synchronous 9464D tumor model, CpG-PBNP-PTT induces complete tumor regression on the treated flank and significantly slows tumor progression on the untreated flank, improving animal survival. These findings demonstrate that localized administration of the CpG-PBNP-PTT nanoimmunotherapy drives potent systemic T cell responses in solid tumors such as NB and therefore has therapeutic implications for NB.

Staphylococcus aureus Protection-Related Type 3 Cell-Mediated Immune Response Elicited by Recombinant Proteins and GM-CSF DNA Vaccine

Staphylococcus aureus mastitis remains a major challenge for dairy farming. Here, 24 mice were immunized and divided into four groups: G1: control; G2: Granulocyte Macrophage Colony-Stimulating Factor (GM-CSF) DNA vaccine; G3: F0F1 ATP synthase subunit α (SAS), succinyl-diaminopimelate (SDD), and cysteinyl-tRNA synthetase (CTS) recombinant proteins; and G4: SAS+SDD+CTS plus GM-CSF DNA vaccine. The lymphocyte subpopulations, and the intracellular interleukin-17A (IL-17A) and interferon-γ production in the draining lymph node cells were immunophenotyped by flow cytometry. The immunophenotyping and lymphocyte proliferation was determined in spleen cells cultured with and without S. aureus stimulus. Immunization with S. aureus recombinant proteins generated memory cells in draining lymph nodes. Immunization with the three recombinant proteins plus GM-CSF DNA led to an increase in the percentage of IL-17A⁺ cells among overall CD44⁺ (memory), T CD4⁺, CD4⁺ T CD44⁺ CD27^-, γδ TCR, γδ TCR⁺ CD44⁺ CD27⁺, and TCRVγ4⁺ cells. Vaccination with S. aureus recombinant proteins associated with GM-CSF DNA vaccine downregulated T_H2 immunity. Immunization with the three recombinant proteins plus the GM-CSF DNA led to a proliferation of overall memory T, CD4⁺, and CD4⁺ TEM cells upon S. aureus stimulus. This approach fostered type 3 immunity, suggesting the development of a protective immune response against S. aureus.

SARS‑CoV-2 RBD219-N1C1: A yeast-expressed SARS-CoV-2 recombinant receptor-binding domain candidate vaccine stimulates virus neutralizing antibodies and T-cell immunity in mice

There is an urgent need for an accessible and low-cost COVID-19 vaccine suitable for low- and middle-income countries. Here, we report on the development of a SARS-CoV-2 receptor-binding domain (RBD) protein, expressed at high levels in yeast (Pichia pastoris), as a suitable vaccine candidate against COVID-19. After introducing two modifications into the wild-type RBD gene to reduce yeast-derived hyperglycosylation and improve stability during protein expression, we show that the recombinant protein, RBD219-N1C1, is equivalent to the wild-type RBD recombinant protein (RBD219-WT) in an in vitro ACE-2 binding assay. Immunogenicity studies of RBD219-N1C1 and RBD219-WT proteins formulated with Alhydrogel® were conducted in mice, and, after two doses, both the RBD219-WT and RBD219-N1C1 vaccines induced high levels of binding IgG antibodies. Using a SARS-CoV-2 pseudovirus, we further showed that sera obtained after a two-dose immunization schedule of the vaccines were sufficient to elicit strong neutralizing antibody titers in the 1:1,000 to 1:10,000 range, for both antigens tested. The vaccines induced IFN-γ IL-6, and IL-10 secretion, among other cytokines. Overall, these data suggest that the RBD219-N1C1 recombinant protein, produced in yeast, is suitable for further evaluation as a human COVID-19 vaccine, in particular, in an Alhydrogel® containing formulation and possibly in combination with other immunostimulants.

Metabolic and Immunological Subtypes of Esophageal Cancer Reveal Potential Therapeutic Opportunities

BACKGROUND

Esophageal cancer has the sixth highest rate of cancer-associated deaths worldwide, with many patients displaying metastases and chemotherapy resistance. We sought to find subtypes to see if precision medicine could play a role in finding new potential targets and predicting responses to therapy. Since metabolism not only drives cancers but also serves as a readout, metabolism was examined as a key reporter for differences.

METHODS

Unsupervised and supervised classification methods, including hierarchical clustering, partial least squares discriminant analysis, k-nearest neighbors, and machine learning techniques, were used to discover and display two major subgroups. Genes, pathways, gene ontologies, survival, and immune differences between the groups were further examined, along with biomarkers between the groups and against normal tissue.

RESULTS

Esophageal cancer had two major unique metabolic profiles observed between the histological subtypes esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). The metabolic differences suggest that ESCC depends on glycolysis, whereas EAC relies more on oxidative metabolism, catabolism of glycolipids, the tricarboxylic acid (TCA) cycle, and the electron transport chain. We also noted a robust prognostic risk associated with COQ3 expression. In addition to the metabolic alterations, we noted significant alterations in key pathways regulating immunity, including alterations in cytokines and predicted immune infiltration. ESCC appears to have increased signature associated with dendritic cells, Th17, and CD8 T cells, the latter of which correlate with survival in ESCC. We bioinformatically observed that ESCC may be more responsive to checkpoint inhibitor therapy than EAC and postulate targets to enhance therapy further. Lastly, we highlight correlations between differentially expressed enzymes and the potential immune status.

CONCLUSION

Overall, these results highlight the extreme differences observed between the histological subtypes and may lead to novel biomarkers, therapeutic strategies, and differences in therapeutic response for targeting each esophageal cancer subtype.

Cellular Immunotherapy Targeting Cancer Stem Cells: Preclinical Evidence and Clinical Perspective

The term “cancer stem cells” (CSCs) commonly refers to a subset of tumor cells endowed with stemness features, potentially involved in chemo-resistance and disease relapses. CSCs may present peculiar immunogenic features influencing their homeostasis within the tumor microenvironment. The susceptibility of CSCs to recognition and targeting by the immune system is a relevant issue and matter of investigation, especially considering the multiple emerging immunotherapy strategies. Adoptive cellular immunotherapies, especially those strategies encompassing the genetic redirection with chimeric antigen receptors (CAR), hold relevant promise in several tumor settings and might in theory provide opportunities for selective elimination of CSC subsets. Initial dedicated preclinical studies are supporting the potential targeting of CSCs by cellular immunotherapies, indirect evidence from clinical studies may be derived and new studies are ongoing. Here we review the main issues related to the putative immunogenicity of CSCs, focusing on and highlighting the existing evidence and opportunities for cellular immunotherapy approaches with T and non-T antitumor lymphocytes.

SARS-CoV-2 RBD219-N1C1: A Yeast-Expressed SARS-CoV-2 Recombinant Receptor-Binding Domain Candidate Vaccine Stimulates Virus Neutralizing Antibodies and T-cell Immunity in Mice

There is an urgent need for an accessible and low-cost COVID-19 vaccine suitable for low- and middle-income countries. Here we report on the development of a SARS-CoV-2 receptor-binding domain (RBD) protein, expressed at high levels in yeast ( Pichia pastoris ), as a suitable vaccine candidate against COVID-19. After introducing two modifications into the wild-type RBD gene to reduce yeast-derived hyperglycosylation and improve stability during protein expression, we show that the recombinant protein, RBD219-N1C1, is equivalent to the wild-type RBD recombinant protein (RBD219-WT) in an in vitro ACE-2 binding assay. Immunogenicity studies of RBD219-N1C1 and RBD219-WT proteins formulated with Alhydrogel ^® were conducted in mice, and, after two doses, both the RBD219-WT and RBD219-N1C1 vaccines induced high levels of binding IgG antibodies. Using a SARS-CoV-2 pseudovirus, we further showed that sera obtained after a two-dose immunization schedule of the vaccines were sufficient to elicit strong neutralizing antibody titers in the 1:1,000 to 1:10,000 range, for both antigens tested. The vaccines induced IFN-γ, IL-6, and IL-10 secretion, among other cytokines. Overall, these data suggest that the RBD219-N1C1 recombinant protein, produced in yeast, is suitable for further evaluation as a human COVID-19 vaccine, in particular, in an Alhydrogel ^® containing formulation and possibly in combination with other immunostimulants.

Levels of low-molecular-weight hyaluronan in periodontitis-treated patients and its immunostimulatory effects on CD4+ T lymphocytes

OBJECTIVES

During periodontitis, chronic inflammation triggers soft tissue breakdown, and hyaluronan is degraded into fragments of low molecular weight (LMW-HA). This investigation aimed to elucidate whether LMW-HA fragments with immunogenic potential on T lymphocytes remain in periodontal tissues after periodontal treatment.

MATERIALS AND METHODS

GCF samples were obtained from 15 periodontitis-affected patients and the LMW-HA, RANKL, and OPG levels were analyzed before and after 6 months of periodontal treatment by ELISA. Eight healthy individuals were analyzed as controls. Besides, human T lymphocytes were purified, exposed to infected dendritic cells, and pulsed with LMW-HA. Non-treated T lymphocytes were used as control. The expression levels of the transcription factors and cytokines that determine the Th1, Th17, and Th22 lymphocyte differentiation and function were analyzed by RT-qPCR. Similarly, the expression levels of RANKL and CD44 were analyzed.

RESULTS

In the GCF samples of periodontitis-affected patients, higher levels of LMW-HA were detected when compared with those of healthy individuals (52.1 ± 15.4 vs. 21.4 ± 12.2, p < 0.001), and these increased levels did not decrease after periodontal therapy (52.1 ± 15.4 vs. 45.7 ± 15.9, p = 0.158). Similarly, the RANKL levels and RANKL/OPG ratios did not change after periodontal therapy. Furthermore, in human T lymphocytes, LMW-HA induced higher expression levels of the Th1, Th17, and Th22-related transcription factors and cytokines, as well as CD44 and RANKL, as compared with non-treated cells.

CONCLUSIONS

In some patients, increased levels of LMW-HA persist in periodontal tissues after conventional periodontal therapy, and these remaining LMW-HA fragments with immunostimulatory potential could induce the polarization of a pathologic Th1/Th17/Th22-pattern of immune response on T lymphocytes.

CLINICAL RELEVANCE

The persistence of increased levels of LMW-HA in periodontal tissues after periodontal therapy could favor the recurrence of the disease and further breakdown of periodontal supporting tissues.

Age-associated Ligand-receptor Interactions Imputed from Nasopharyngeal Transcriptomes of COVID-19 Patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has exhibited different clinical manifestations amongst various age cohorts. As the immune microenvironment may play a role in clinical progression, it is crucial to examine molecular interactions to gain insight into host response. Therefore, to elucidate any differences in host response related to age, the present study imputed ligand-receptor interactions within the nasopharyngeal immune microenvironment in patients affected with SARS-COV-2. Tissue purities, the proportion of non-immune cells in the tissue sample, of 467 nasopharyngeal transcriptome profiles were estimated using known mRNA expression signatures of stromal/immune cells. Using the purity estimates and bulk tissue expression values, non-negative linear regression was used to estimate average expression of each gene in the stromal/tumor compartments. The inferred expression profiles were annotated with a curated database of ligand-receptor interactions and assumed as reasonable proxies for the law of mass action, allowing for quantification of directional ligand-receptor complex concentrations under equilibrium. It was found that older patients (>60 years) exhibited decreased interactions with receptors selectin L receptor SELL and increased interactions with pro-inflammatory chemokine receptors CXCR2 and CCR1. Younger patients showed increased interactions with various members of the TNF receptor super family (TNFRSF). The interactions were further related to immune cell subtypes, with older patients predicted to have less CD8+ and CD4+ resting T cells but increased neutrophil proportions. Collectively, the results suggest certain ligand-receptor interactions of the nasopharyngeal immune microenvironment are age-associated in response to SARS-CoV-2.

Developmental Dysfunction of the Central Nervous System Lymphatics Modulates the Adaptive Neuro-Immune Response in the Perilesional Cortex in a Mouse Model of Traumatic Brain Injury

Rationale

The recently discovered meningeal lymphatic vessels (mLVs) have been proposed to be the missing link between the immune and the central nervous system. The role of mLVs in modulating the neuro-immune response following a traumatic brain injury (TBI), however, has not been analyzed. Parenchymal T lymphocyte infiltration has been previously reported as part of secondary events after TBI, suggestive of an adaptive neuro-immune response. The phenotype of these cells has remained mostly uncharacterized. In this study, we identified subpopulations of T cells infiltrating the perilesional areas 30 days post-injury (an early-chronic time point). Furthermore, we analyzed how the lack of mLVs affects the magnitude and the type of T cell response in the brain after TBI.

Methods

TBI was induced in K14-VEGFR3-Ig transgenic (TG) mice or in their littermate controls (WT; wild type), applying a controlled cortical impact (CCI). One month after TBI, T cells were isolated from cortical areas ipsilateral or contralateral to the trauma and from the spleen, then characterized by flow cytometry. Lesion size in each animal was evaluated by MRI.

Results

In both WT and TG-CCI mice, we found a prominent T cell infiltration in the brain confined to the perilesional cortex and hippocampus. The majority of infiltrating T cells were cytotoxic CD8+ expressing a CD44hiCD69+ phenotype, suggesting that these are effector resident memory T cells. K14-VEGFR3-Ig mice showed a significant reduction of infiltrating CD4+ T lymphocytes, suggesting that mLVs could be involved in establishing a proper neuro-immune response. Extension of the lesion (measured as lesion volume from MRI) did not differ between the genotypes. Finally, TBI did not relate to alterations in peripheral circulating T cells, as assessed one month after injury.

Conclusions

Our results are consistent with the hypothesis that mLVs are involved in the neuro-immune response after TBI. We also defined the resident memory CD8+ T cells as one of the main population activated within the brain after a traumatic injury.

Oncolytic HSV Therapy Modulates Vesicular Trafficking Inducing Cisplatin Sensitivity and Antitumor Immunity

PURPOSE

Here we investigated the impact of oncolytic herpes simplex virus (HSV) treatment on cisplatin sensitivity of platinum-resistant ovarian cancer, and the impact of the combination on immunotherapy.

EXPERIMENTAL DESIGN

Therapeutic efficacy of the combination was assessed in platinum-resistant human and murine ovarian cancer peritoneal metastatic mouse models (n = 9-10/group). RNA sequencing along with flow cytometry of splenocytes from treated mice was employed to examine the effect of antitumor immune response (n = 3/group). Anti-PD-1 antibody was performed to evaluate impact on checkpoint inhibition in vivo.

RESULTS

Gene Ontology pathway analysis uncovered disruption of cellular extracellular vesicle (EV)-related pathways in infected cells (FDR = 2.97E-57). Mechanistically, we identified reduced expression of transporters expressed on EV implicated in cisplatin efflux. The increased cisplatin retention led to increased cisplatin-DNA adducts, which resulted in micronuclei and the subsequent activation of cGAS-STING pathway with a significant activation of innate immune cells and translated to an increase in antitumor immunity and efficacy. In mice bearing platinum-resistant ovarian cancer, we also observed a feedback induction of PD-L1 on tumor cells, which sensitized combination-treated mice to anti-PD-1 immune checkpoint therapy.

CONCLUSIONS

To our knowledge, this is the first report to show HSV-induced cisplatin retention in infected cells. The consequential increased damaged DNA was then expelled from cells as micronuclei which resulted in induction of inflammatory responses and education of antitumor immunity. The combination therapy also created an environment that sensitized tumors to immune checkpoint therapy.

MEK inhibition reprograms CD8+ T lymphocytes into memory stem cells with potent antitumor effects

Regenerative stem cell-like memory (TSCM) CD8+ T cells persist longer and produce stronger effector functions. We found that MEK1/2 inhibition (MEKi) induces TSCM that have naive phenotype with self-renewability, enhanced multipotency and proliferative capacity. This is achieved by delaying cell division and enhancing mitochondrial biogenesis and fatty acid oxidation, without affecting T cell receptor-mediated activation. DNA methylation profiling revealed that MEKi-induced TSCM cells exhibited plasticity and loci-specific profiles similar to bona fide TSCM isolated from healthy donors, with intermediate characteristics compared to naive and central memory T cells. Ex vivo, antigenic rechallenge of MEKi-treated CD8+ T cells showed stronger recall responses. This strategy generated T cells with higher efficacy for adoptive cell therapy. Moreover, MEKi treatment of tumor-bearing mice also showed strong immune-mediated antitumor effects. In conclusion, we show that MEKi leads to CD8+ T cell reprogramming into TSCM that acts as a reservoir for effector T cells with potent therapeutic characteristics.

Mechanisms That Underly T Cell Immunity in Graves' Orbitopathy

Graves' orbitopathy (GO), also known as thyroid-associated ophthalmopathy, is the most common ocular abnormality of Graves' disease. It is a disfiguring, invalidating, and potentially blinding orbital disease mediated by an interlocking and complicated immune network. Self-reactive T cells directly against thyroid-stimulating hormone receptor-bearing orbital fibroblasts contribute to autoimmune inflammation and tissue remodeling in GO orbital connective tissues. To date, T helper (Th) 1 (cytotoxic leaning) and Th2 (antibody leaning) cell subsets and an emerging role of Th17 (fibrotic leaning) cells have been implicated in GO pathogenesis. The potential feedback loops between orbital native residential CD34^- fibroblasts, CD34⁺ infiltrating fibrocytes, and effector T cells may affect the T cell subset bias and the skewed pattern of cytokine production in the orbit, thereby determining the outcomes of GO autoimmune reactions. Characterization of the T cell subsets that drive GO and the cytokines they express may significantly advance our understanding of orbital autoimmunity and the development of promising therapeutic strategies against pathological T cells.

Ab initio spillover compensation in mass cytometry data

Signal intensity measured in a mass cytometry (CyTOF) channel can often be affected by the neighboring channels due to technological limitations. Such signal artifacts are known as spillover effects and can substantially limit the accuracy of cell population clustering. Current approaches reduce these effects by using additional beads for normalization purposes known as single-stained controls. While effective in compensating for spillover effects, incorporating single-stained controls can be costly and require customized panel design. This is especially evident when executing large-scale immune profiling studies. We present a novel statistical method, named CytoSpill that independently quantifies and compensates the spillover effects in CyTOF data without requiring the use of single-stained controls. Our method utilizes knowledge-guided modeling and statistical techniques, such as finite mixture modeling and sequential quadratic programming, to achieve optimal error correction. We evaluated our method using five publicly available CyTOF datasets obtained from human peripheral blood mononuclear cells (PBMCs), C57BL/6J mouse bone marrow, healthy human bone marrow, chronic lymphocytic leukemia patient, and healthy human cord blood samples. In the PBMCs with known ground truth, our method achieved comparable results to experiments that incorporated single-stained controls. In datasets without ground-truth, our method not only reduced spillover on likely affected markers, but also led to the discovery of potentially novel subpopulations expressing functionally meaningful, cluster-specific markers. CytoSpill (developed in R) will greatly enhance the execution of large-scale cellular profiling of tumor immune microenvironment, development of novel immunotherapy, and the discovery of immune-specific biomarkers. The implementation of our method can be found at https://github.com/KChen-lab/CytoSpill.git.

The Methyltransferase DOT1L Controls Activation and Lineage Integrity in CD4+ T Cells during Infection and Inflammation

CD4⁺ T helper (Th) cell differentiation is controlled by lineage-specific expression of transcription factors and effector proteins, as well as silencing of lineage-promiscuous genes. Lysine methyltransferases (KMTs) comprise a major class of epigenetic enzymes that are emerging as important regulators of Th cell biology. Here, we show that the KMT DOT1L regulates Th cell function and lineage integrity. DOT1L-dependent dimethylation of lysine 79 of histone H3 (H3K79me2) is associated with lineage-specific gene expression. However, DOT1L-deficient Th cells overproduce IFN-γ under lineage-specific and lineage-promiscuous conditions. Consistent with the increased IFN-γ response, mice with a T-cell-specific deletion of DOT1L are susceptible to infection with the helminth parasite Trichuris muris and are resistant to the development of allergic lung inflammation. These results identify a central role for DOT1L in Th2 cell lineage commitment and stability and suggest that inhibition of DOT1L may provide a therapeutic strategy to limit type 2 immune responses.

Mouse bone marrow-derived mesenchymal stem cells acquire immunogenicity concurrent with differentiation to insulin-producing cells

BACKGROUND

Although mesenchymal stem cells (MSCs) are regarded as immune-elusive and even immunosuppressive, recent evidence suggests that allogeneic immune response might is inevitable in the case of some lineages differentiated from MSCs. Regarding the importance of allogeneic IPCs and MSCs in pre-clinical and clinical studies, the present study aimed to investigate the possible changes in the immunogenicity of MSCs during the differentiation to IPCs in a murine model of allogeneic transplantation.

MATERIAL AND METHODS

Two mouse strains, C57BL/6 (H2D^b) and BALB/c (H2D^d) were selected to establish an allogeneic cell transplantation model. Bone marrow MSCs were differentiated into IPCs and the expression of H2D, CD80, and Qa-2 molecules were evaluated via flowcytometry on MSCs and IPCs. The differentiated and undifferentiated MSCs were encountered to allogeneic splenocytes and the proliferation, CD44 activation marker, and cytokine release in the splenocytes were evaluated.

RESULTS

IPCs exhibited increased expression of MHC-I and CD80 that elicited an allogenic response including the activation-induced proliferation of splenocytes, activation of CD4⁺ T cells, and IFNγ response.

CONCLUSIONS

MSCs acquire immunogenicity after differentiation to functional IPCs, which might cause decreased efficacy in the case of allogeneic transplantation. Careful precautions might be critical for saving the IPCs against the detrimental allogeneic responses.

Targeting Cancer Stem Cells by Genetically Engineered Chimeric Antigen Receptor T Cells

The term cancer stem cell (CSC) starts 25 years ago with the evidence that CSC is a subpopulation of tumor cells that have renewal ability and can differentiate into several distinct linages. Therefore, CSCs play crucial role in the initiation and the maintenance of cancer. Moreover, it has been proposed throughout several studies that CSCs are behind the failure of the conventional chemo-/radiotherapy as well as cancer recurrence due to their ability to resist the therapy and their ability to re-regenerate. Thus, the need for targeted therapy to eliminate CSCs is crucial; for that reason, chimeric antigen receptor (CAR) T cells has currently been in use with high rate of success in leukemia and, to some degree, in patients with solid tumors. This review outlines the most common CSC populations and their common markers, in particular CD133, CD90, EpCAM, CD44, ALDH, and EGFRVIII, the interaction between CSCs and the immune system, CAR T cell genetic engineering and signaling, CAR T cells in targeting CSCs, and the barriers in using CAR T cells as immunotherapy to treat solid cancers.

Dendritic Cells Generated From Mops condylurus, a Likely Filovirus Reservoir Host, Are Susceptible to and Activated by Zaire Ebolavirus Infection

Ebola virus infection of human dendritic cells (DCs) induces atypical adaptive immune responses and thereby exacerbates Ebola virus disease (EVD). Human DCs, infected with Ebola virus aberrantly express low levels of the DC activation markers CD80, CD86, and MHC class II. The T cell responses ensuing are commonly anergic rather than protective against EVD. We hypothesize that DCs derived from potential reservoir hosts such as bats, which do not develop disease signs in response to Ebola virus infection, would exhibit features associated with activation. In this study, we have examined Zaire ebolavirus (EBOV) infection of DCs derived from the Angolan free-tailed bat species, Mops condylurus. This species was previously identified as permissive to EBOV infection in vivo, in the absence of disease signs. M. condylurus has also been recently implicated as the reservoir host for Bombali ebolavirus, a virus species that is closely related to EBOV. Due to the absence of pre-existing M. condylurus species-specific reagents, we characterized its de novo assembled transcriptome and defined its phylogenetic similarity to other mammals, which enabled the identification of cross-reactive reagents for M. condylurus bone marrow-derived DC (bat-BMDC) differentiation and immune cell phenotyping. Our results reveal that bat-BMDCs are susceptible to EBOV infection as determined by detection of EBOV specific viral RNA (vRNA). vRNA increased significantly 72 h after EBOV-infection and was detected in both cells and in culture supernatants. Bat-BMDC infection was further confirmed by the observation of GFP expression in DC cultures infected with a recombinant GFP-EBOV. Bat-BMDCs upregulated CD80 and chemokine ligand 3 (CCL3) transcripts in response to EBOV infection, which positively correlated with the expression levels of EBOV vRNA. In contrast to the aberrant responses to EBOV infection that are typical for human-DC, our findings from bat-BMDCs provide evidence for an immunological basis of asymptomatic EBOV infection outcomes.

Mass cytometry identifies distinct CD4+ T cell clusters distinguishing HIV-1-infected patients according to antiretroviral therapy initiation

Recent guidelines recommend antiretroviral therapy (ART) to be administered as early as possible during HIV-1 infection. Few studies addressed the immunological benefit of commencing ART during the acute phase of infection. We used mass cytometry to characterize blood CD4+ T cells from HIV-1-infected patients who initiated ART during acute or chronic phase of infection. Using this method, we analyzed a large number of markers on millions of individual immune cells. The results revealed that CD4+ T cell clusters with high expression of CD27, CD28, CD127, and CD44, whose function involves T cell migration to inflamed tissues and survival, are more abundant in healthy controls and patients initiating ART during the acute phase; on the contrary, CD4+ T cell clusters in patients initiating ART during the chronic phase had reduced expression of these markers. The results are suggestive of a better preserved immune function in HIV-1-infected patients initiating ART during acute infection.

Lipid nanoparticles that deliver IL-12 messenger RNA suppress tumorigenesis in MYC oncogene-driven hepatocellular carcinoma

Interleukin-12 (IL-12) is a promising candidate for cancer immunotherapy because of its ability to activate a number of host immune subsets that recognize and destroy cancer cells. We found that human hepatocellular carcinoma (HCC) patients with higher than median levels of IL-12 have significantly favorable clinical outcomes. Here, we report that a messenger RNA (mRNA) lipid nanoparticle delivering IL-12 (IL-12-LNP) slows down the progression of MYC oncogene-driven HCC. IL-12-LNP was well distributed within the HCC tumor and was not associated with significant animal toxicity. Treatment with IL-12-LNP significantly reduced liver tumor burden measured by dynamic magnetic resonance imaging (MRI), and increased survival of MYC-induced HCC transgenic mice in comparison to control mice. Importantly, IL-12-LNP exhibited no effect on transgenic MYC levels confirming that its therapeutic efficacy was not related to the downregulation of a driver oncogene. IL-12-LNP elicited marked infiltration of activated CD44⁺ CD3⁺ CD4⁺ T helper cells into the tumor, and increased the production of Interferon γ (IFNγ). Collectively, our findings suggest that IL-12-LNP administration may be an effective immunotherapy against HCC.

Cancer stem cells as targets for immunotherapy

Current cancer therapies target the bulk of the tumour, while a population of highly resistant tumour cells may be able to repopulate the tumour and metastasize to new sites. Cancer cells with such stem cell-like characteristics can be identified based on their phenotypical and/or functional features which may open up ways for their targeted elimination. In this review we discuss potential off-target effects of inhibiting cancer stem-cell self-renewal pathways on immune cells, and summarize some recent immunological studies specifically targeting cancer stem cells based on their unique antigen expression.

Regulation of Orbital Fibrosis and Adipogenesis by Pathogenic Th17 Cells in Graves Orbitopathy

CONTEXT

T helper (Th)17 cells are correlated with many human autoimmune disorders, including Graves disease, and may play key roles in the pathogenesis of Graves orbitopathy (GO).

OBJECTIVE

To study the phenotype of Th17 cells in patients with GO and healthy subjects, investigate the fibrosis and adipogenesis in orbital fibroblasts (OFs) modulated by interleukin (IL)-17A, and determine the interaction between Th17 cells and OFs.

DESIGN/SETTING/PARTICIPANTS

Blood samples and orbital tissues from GO patients and healthy controls were collected.

MAIN OUTCOME MEASURES

We conducted multicolor flow cytometry, immunohistochemical and immunofluorescent stainings, Western blotting, a PathScan intracellular signaling assay, Luminex and enzyme-linked immunosorbent assays, and protein mass spectrum.

RESULTS

Interferon-γ- and IL-22-expressing Th17 cells are increased in GO patients, which are positively related to clinical activity score. Costimulatory molecules are highly expressed in GO orbits and most GO OFs are CD90+. IL-17A promotes TGF-β-induced fibrosis in CD90+ OFs but impedes 15-deoxy-Δ12,14-prostaglandin J2-induced adipogenesis in CD90- OFs. Th17 cells promote proinflammatory cytokine secretion in both CD90+ and CD90- OFs. Meanwhile, both CD90+ and CD90- OFs contribute to Th17 cell differentiation through prostaglandin E2 production, which can be attenuated by indomethacin. Furthermore, Th17 cells upregulate costimulatory molecule expression on OFs.

CONCLUSION

Our findings unravel the pathogenicity of IL-17A in the initiation and progression of GO. In-depth interpretation of the molecular basis of OFs delineated by CD90 and Th17-OF interaction will help to afford a novel approach to better therapeutic strategies for GO.

Early growth response 2 and Egr3 are unique regulators in immune system

The immune system is evolved to defend the body against pathogens and is composed of thousands of complicated and intertwined pathways, which are highly controlled by processes such as transcription and repression of cellular genes. Sometimes the immune system malfunctions and a break down in self-tolerance occurs. This lead to the inability to distinguish between self and non-self and cause attacks on host tissues, a condition also known as autoimmunity, which can result in chronic debilitating diseases. Early growth response genes are family of transcription factors comprising of four members, Egr1, Egr2, Egr3 and Egr4. All of which contain three cyc2-His2 zinc fingers. Initially, Egr2 function was identified in the regulation of peripheral nerve myelination, hindbrain segmentation. Egr3, on the other hand, is highly expressed in muscle spindle development. Egr2 and Egr3 are induced due to the antigen stimulation and this signaling is implemented through the B and T cell receptors in the adaptive immunity. T cell receptor signaling plays a key role in Egr 2 and 3 expressions via their interaction with NFAT molecules. Egr 2 and 3 play a crucial role in regulation of the immune system and their involvement in B and T cell activation, anergy induction and preventing the autoimmune disease has been investigated. The deficiency of these transcription factors has been associated to deficient Cbl-b expression, a resistant to anergy phenotype, and expression of effector and activated T cells.

Cyp1b1-mediated suppression of lymphoid progenitors in bone marrow by polycyclic aromatic hydrocarbons coordinately impacts spleen and thymus: a selective role for the Ah Receptor

Bone marrow (BM) hematopoietic stem cells differentiate to common lymphoid progenitors (CLP) that emigrate to the thymus to form T cells or differentiate into immature B cells that then migrate to the spleen for maturation. Rapid in vivo suppression of BM progenitor cells by a single oral or intraperitoneal dose of 7,12-dimethylbenz(a)anthracene (DMBA) subsequently decreased mature lymphoid populations in BM, spleen, and thymus. These suppressions depended on BM CYP1B1, but not on aryl hydrocarbon receptor (AhR) activity. Suppression of pre-B colony formation at 6 h, correlated with subsequent decreases in mature BM, spleen, and thymus populations (48-168 h). Thymus T-cell ratios were unaffected, suggesting low local toxicity. DMBA treatment suppressed progenitor cells 24-h post treatment in wild type (WT), AhRb mice, but not in Cyp1b1-ko mice. The stem cell populations were sustained. Benzo(a)pyrene (BP) mediated a similar progenitor suppression up to 6 h, but reversal rapidly ensued. This recovery was absent in mice with a polycyclic aromatic hydrocarbon (PAH)-resistant, AhRd genotype. This AhR-dependent progenitor recovery with BP induction accounts for the absence of suppression of B220+ BM and spleen populations at 48-168 h. However, DMBA and BP produced similar profiles for thymus cell suppression, independent of AhR genotype. Thus, lymphoid progenitors may exit the BM to the thymus prior to the BP reversal. This progenitor recovery is associated with elevated chemokines and cytokines that depend on AhR-mediated induction of CYP1A1. This response increased constitutively in Cyp1b1-ko BM, demonstrating that CYP1B1 metabolizes local stimulants that impact a basal progenitor protection process.