Decisions about dendritic cells: past, present, and future

Advances in dendritic cell-based therapeutic tumor vaccines

Dendritic cell-based therapeutic tumor vaccines are an active immunotherapy that has been commonly tried in the clinic,traditional treatment modalities for malignant tumors, such as surgery, radiotherapy and chemotherapy, have the disadvantages of high recurrence rates and side effects. The dendritic cell vaccination destroys cells from tumors by means of the patient's own system of immunity, a very promising treatment. However, due to the suppression of the tumor immune microenvironment, the difficulty of screening for optimal specific antigens, and the high technical difficulty of vaccine production. Most tumor vaccines currently available in the clinic have failed to produce significant clinical therapeutic effects. In this review, the fundamentals of therapeutic dendritic cells vaccine therapy are briefly outlined, with a focus on the progress of therapeutic Dendritic cells vaccine research in the clinic and the initiatives undertaken to enhance dendritic cell vaccinations' anti-tumor effectiveness. It is believed that through the continuous exploration of novel therapeutic strategies, therapeutic dendritic cells vaccines can play a greater role in improving tumor treatment for tumor patients.

Mechanoregulation of lymphocyte cytotoxicity

Cytotoxic lymphocytes counter intracellular pathogens and cancer by recognizing and destroying infected or transformed target cells. The basis for their function is the cytolytic immune synapse, a structurally stereotyped cell-cell interface through which lymphocytes deliver toxic proteins to target cells. The immune synapse is a highly dynamic contact capable of exerting nanonewton-scale forces against the target cell. In recent years, it has become clear that the interplay between these forces and the biophysical properties of the target influences the entirety of the cytotoxic response, from the initial activation of cytotoxic lymphocytes to the release of dying target cells. As a result, cellular cytotoxicity has become an exemplar of the ways in which biomechanics can regulate immune cell activation and effector function. This Review covers recent progress in this area, which has prompted a reconsideration of target cell killing from a more mechanobiological perspective.

The Soluble Cytoplasmic Tail of CD45 (ct-CD45) Regulates Dendritic Cell Activation and Function via TLR4 Signaling

The soluble cytoplasmic tail of the prototypic receptor-like protein tyrosine phosphatase (PTP) CD45 (ct-CD45) is cleaved and released into the human plasma by activated phagocytes. Released ct-CD45 was found to inhibit T cell proliferation and cytokine production via engagement of Toll-like receptor 4 (TLR4). In this study, we analyzed the impact of the ct-CD45/TLR4 pathway on the function of human monocyte-derived dendritic cells (DCs). We could demonstrate that activation of DCs by ct-CD45 upregulated the expression of certain cell surface markers (e.g., CD71 and CD86) and induced IL-10 production via TLR4. Yet, in contrast to stimulation with LPS, other typical cell surface markers and cytokines were not upregulated or induced in DCs by ct-CD45. The T cell proliferation-stimulatory capacity of DCs was not modulated by ct-CD45 treatment. However, treatment of DCs with ct-CD45 modulated the cytokine profile in co-cultured T cells. While IFN-γ production induced by DCs was strongly inhibited, the release of IL-4 was increased in T cells upon stimulation with ct-CD45-treated DCs. In contrast, ct-CD45-stimulated DCs induced IL-2 and IL-10 production in co-cultured T cells comparable to untreated DCs. In summary, we could demonstrate that ct-CD45 acts as an immunoregulatory factor for DCs via a non-canonical TLR4-dependent activation pathway.

Rejuvenation of Tumor-Specific T Cells via Ultrahigh DAR Antibody-Polymeric Imidazoquinoline Complexes: Coordinated Targeting of PDL1 and Efficient TLR7/8 Activation in Intratumoral Dendritic Cells

Intratumoral dendritic cells (DCs) are pivotal in tumor treatment due to their immature and pro-tumoral state induced by the tumor microenvironment. Clinically, these immature DCs correlate with disease progression and recurrence, adversely affecting prognosis. Activation of DCs by the TLR7/8 agonist imidazoquinoline (IMDQ) has yielded promising results, but they are limited by systemic inflammation risks, and high programmed death ligand 1 (PDL1) expression on DCs impedes CD8+ T cell activity. Thus, the study introduces an antibody-polymeric IMDQ complex (αPDL1-PLG-IMDQ) with an ultrahigh drug-to-antibody ratio, where αPDL1 is conjugated to Fc-binding peptides on polymeric IMDQ. This complex targets high PDL1-expressing intratumoral DCs with high probability, inducing PDL1-mediated endocytosis to deliver IMDQ to TLR7/8 within endosomes, effectively activating DCs (CD11c+MHC II+: 2.33% versus 1.09%, CD11c+CD86+: 2.49% versus 1.00% on tumors compared to phosphate-buffered saline treatment) and priming T cells. It also blocks PDL1/PD1 interactions, enhancing tumor-specific T-cell activation and memory. Notably, αPDL1-PLG-IMDQ achieved a 97% tumor inhibition rate, prevented tumor regrowth in rechallenge experiments, and reduced lung metastases of tumors by 83%. These findings underscore its potential for intratumoral DC-targeted immunotherapy and novel systemic IMDQ and checkpoint inhibitor combinations.

Cross-priming in cancer immunology and immunotherapy

Cytotoxic T cell immune responses against cancer crucially depend on the ability of a subtype of professional antigen-presenting cells termed conventional type 1 dendritic cells (cDC1s) to cross-present antigens. Cross-presentation comprises redirection of exogenous antigens taken from other cells to the major histocompatibility complex class I antigen-presenting machinery. In addition, once activated and having sensed viral moieties or T helper cell cooperation via CD40-CD40L interactions, cDC1s provide key co-stimulatory ligands and cytokines to mount and sustain CD8+ T cell immune responses. This regulated process of cognate T cell activation is termed cross-priming. In cancer mouse models, CD8+ T cell cross-priming by cDC1s is crucial for the efficacy of most, if not all, immunotherapy strategies. In patients with cancer, the presence and abundance of cDC1s in the tumour microenvironment is markedly associated with the level of T cell infiltration and responsiveness to immune checkpoint inhibitors. Therapeutic strategies to increase the numbers of cDC1s using FMS-like tyrosine kinase 3 ligand (FLT3L) and/or their activation status show evidence of efficacy in cancer mouse models and are currently being tested in initial clinical trials with promising results so far.

Multi-Epitope DC Vaccines with Melanoma Antigens for Immunotherapy of Melanoma

Background/Objectives: The revolution for the treatment of melanoma came with the approval of checkpoint blockade antibodies. However, a substantial proportion of patients show primary or secondary resistance to this type of immunotherapy, indicating the need for alternative therapeutic strategies. Dendritic cells (DCs) of the skin are prime targets for vaccination approaches due to their potential to prime naïve T cells and their accessibility. This study aimed to develop and evaluate novel vaccines targeting the C-type lectin receptor DEC-205 to deliver melanoma-associated antigenic peptides to skin DCs. Methods: We cloned MHC-I-restricted peptides from the glycoprotein (gp)10025-33 and Tyrosinase-related protein (trp)2180-188 into the DEC-205 antibody sequence with modified peptide cutting sites from the OVA257-264 SIINFEKL peptide. We tested their potential to induce CD8+ T cell responses in both in vitro and in vivo settings. Tumor growth inhibition was evaluated in the transplantable B16.OVA melanoma murine model using a multi-epitope DC-based vaccine combining both peptides. Results: The cross-presentation of both gp100 and trp2 peptides was confirmed in vivo when peptide sequences were flanked by the OVA257-264 peptide cutting sites. Moreover, the combination of both antigenic peptides into a multi-epitope DC vaccine was required to inhibit B16.OVA melanoma growth. Conclusions: Our findings suggest that a DC-targeted vaccination approach using multiple epitopes deriving from melanoma antigens could represent a promising strategy for melanoma therapy.

Fumonisin B1 Exerts Immunosuppressive Effects Through Cytoskeleton Remodeling and Function Attenuation of Mature Dendritic Cells

Fumonisin B1 (FB1) is one of the most toxic mycotoxins and is harmful to humans and animals due to its hepatotoxicity, immunotoxicity and carcinogenicity. However, the mechanism of its immunosuppressive effect is still under investigation. Dendritic cells (DCs) are the most potent professional antigen-presenting cells, and their differentiation, maturation and immunomodulatory functions are closely related to the immunotoxicity of certain mycotoxins. Migratory capacity is a prerequisite for mature DCs (mDCs) to move and present antigens in secondary lymphoid tissue, whereas the mechanical properties and cytoskeletal structure are critical for their migration and immune functions. Therefore, the effects of FB1 on the cell viability, mechanical characteristics, cytoskeletal structure and its binding proteins, migration, co-stimulatory molecules and the immune functions of mDCs were investigated to explore the potential mechanisms of immunotoxicity. The results showed that FB1 could impair the chemotactic migratory capability, the expression of co-stimulatory molecules and the ability of DCs to stimulate T cell proliferation. Further analyses elucidated that the mechanical properties of mDCs were changed, the cytoskeletal structures were reorganized and the expressions of cytoskeleton-binding proteins were regulated. In conclusion, the attenuated migration and immune functions of mDCs caused by FB1 may be related to their altered mechanical properties and cytoskeleton remodeling, which may be one of the action modes for FB1 to exert its immunosuppressive effect.

The epigenetic hallmarks of immune cells in cancer

Targeting the dysregulation of epigenetic mechanisms in cancer has emerged as a promising therapeutic strategy. Although the significant rationale progress of epigenetic therapies in blocking cancer cells, how epigenetic regulation shapes tumor microenvironment (TME) and establishes antitumor immunity remains less understood. Recent study focus has been put on the epigenetic-mediated changes in the fate of immune cells, including the differentiation, expansion, recruitment, functionalization, and exhaustion of T cells, natural killer (NK) cells, tumor-associated macrophages (TAMs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), and B cells within the TME. Here, we review the latest molecular and clinical insights into how DNA modifications, histone modification, and epitranscriptome-related regulations shape immune cells of various cancers. We also discuss opportunities for leveraging epigenetic therapies to improve cancer immunotherapies. This review provides the epigenetic foundations of cancer immunity and proposes the future direction of combination therapies.

Drug Delivery Systems Based on Dendritic-Cell-Derived Exosomes

Exosomes, spherical lipid-bilayered particles secreted by cells, have recently emerged as a novel and highly promising drug delivery system, attracting extensive attention in the field of biomedical research. Dendritic-cell-derived exosomes (DC-Exos) possess surface protein and ligands characteristic of DC cells, such as functional MHC-I and MHC-II, CD80, CD86. These components play a crucial role in immune responses, facilitating antigen uptake, presentation, and the activation of antigen-specific CD4 and CD8 T cells. These properties make them striking and excellent drug delivery vehicles for use in various immune diseases and cancer therapy. This review summarizes and discusses the characteristics, current methods and types of drug loading of DC-Exos. Its surface modifications and application in disease treatment were also discussed, aiming to motivate the development of exosome-based theranostic nanoplatforms and nanotechnology for improved healthcare treatments.

The multifaceted role of SMAD4 in immune cell function

The Transforming Growth Factor-beta (TGF-β) signaling pathway, with SMAD4 as its central mediator, plays a pivotal role in regulating cellular functions, including growth, differentiation, apoptosis, and immune responses. While extensive research has elucidated SMAD4's role in tumorigenesis, its functions within immune cells remain underexplored. This review synthesizes current knowledge on SMAD4's diverse roles in various immune cells such as T cells, B cells, dendritic cells, and macrophages, highlighting its impact on immune homeostasis and pathogen response. Understanding SMAD4's role in immune cells is crucial, as its dysregulation can lead to autoimmune disorders, chronic inflammation, and immune deficiencies. The review emphasizes the significance of SMAD4 in immune regulation, proposing that deeper investigation could reveal novel therapeutic targets for immune-mediated conditions. Insights into SMAD4's involvement in processes like T cell differentiation, B cell class switch recombination, and macrophage polarization underscore its potential as a therapeutic target for a range of diseases, including autoimmune disorders and cancer.

A neoantigen vaccine generates antitumour immunity in renal cell carcinoma

Personalized cancer vaccines (PCVs) can generate circulating immune responses against predicted neoantigens1-6. However, whether such responses can target cancer driver mutations, lead to immune recognition of a patient's tumour and result in clinical activity are largely unknown. These questions are of particular interest for patients who have tumours with a low mutational burden. Here we conducted a phase I trial (ClinicalTrials.gov identifier NCT02950766) to test a neoantigen-targeting PCV in patients with high-risk, fully resected clear cell renal cell carcinoma (RCC; stage III or IV) with or without ipilimumab administered adjacent to the vaccine. At a median follow-up of 40.2 months after surgery, none of the 9 participants enrolled in the study had a recurrence of RCC. No dose-limiting toxicities were observed. All patients generated T cell immune responses against the PCV antigens, including to RCC driver mutations in VHL, PBRM1, BAP1, KDM5C and PIK3CA. Following vaccination, there was a durable expansion of peripheral T cell clones. Moreover, T cell reactivity against autologous tumours was detected in seven out of nine patients. Our results demonstrate that neoantigen-targeting PCVs in high-risk RCC are highly immunogenic, capable of targeting key driver mutations and can induce antitumour immunity. These observations, in conjunction with the absence of recurrence in all nine vaccinated patients, highlights the promise of PCVs as effective adjuvant therapy in RCC.

Recent Advances in the Development and Efficacy of Anti-Cancer Vaccines-A Narrative Review

Immunotherapy is an established and efficient treatment strategy for a variety of malignancies. It aims to boost the anticancer properties of one's own immune system. Several immunotherapeutic options are available, but immune checkpoint blockers represent the most widely known and investigated. Anticancer vaccines represent an evolving area of immunotherapy that stimulate antigen-presenting cells, cytotoxic responses of CD8+ T cells, and the presence of memory T cells, among others. Over the years, different approaches for anticancer vaccines have been studied, such as mRNA and DNA vaccines, together with dendritic cell- and viral vector-based vaccines. Recently, an accumulating number of clinical studies have been performed to analyze the safety and potential efficacy of these agents. The aim of this review is to summarize recent advances regarding different types of therapeutic anticancer vaccines. Furthermore, it will discuss how recent advances in preclinical models can enhance clinical outcomes.

Sequential activation of conventional and plasmacytoid dendritic cells in autoimmune pancreatitis and systemic lupus erythematosus: similarities and dissimilarities

Type 1 autoimmune pancreatitis (AIP) and systemic lupus erythematosus (SLE) are caused by type I IFNs secreted by plasmacytoid dendritic cells (pDCs). Our understanding of the immune consequences before and after pDC activation in SLE is expanding, whereas knowledge on those in AIP are insufficient. In this article, we summarize the similarities and dissimilarities in pDC activation between AIP and SLE. In SLE, neutrophil extracellular traps containing self-DNA, anti-microbial peptides, and endogenous alarmins form anti-DNA antibody complexes, promoting type I IFN production by pDCs. Type I IFNs produced by pDCs function as initiators rather than effectors in SLE, as evidenced by the fact that these cytokines induce the maturation of conventional DCs (cDCs) leading to the expansion of autoreactive T cells and B cells. Notably, type I IFNs produced by pDCs were observed at the maturation phase but not at the induction phase in experimental AIP. Mechanistically, cDCs producing type I IFNs, C-X-C motif chemokine ligand 9 (CXCL9), and CXCL10 are initiator cells of AIP, and C-X-C chemokine receptor 3 (CXCR3)+T helper type 1(Th1) cells migrate to the pancreas in response to CXCL9 and CXCL10. CXCR3+Th1 cells produce C-C chemokine ligand 25 (CCL25) to attract C-C chemokine receptor 9 (CCR9)+pDCs to the pancreas. Pancreatic pDCs producing type I IFNs, CXCL9, CXCL10, and CXCR3+Th1 cells producing CCL25 form a positive feedback loop in which the sensing of intestinal dysbiosis induces large amounts of type I IFNs by pDCs.

Extracellular Vesicle-Based Strategies for Tumor Immunotherapy

Immunotherapy is one of the most promising approaches for cancer management, as it utilizes the intrinsic immune response to target cancer cells. Normally, the human body uses its immune system as a defense mechanism to detect and eliminate foreign objects, including cancer cells. However, cancers develop a 'switch off' mechanism, known as immune checkpoint proteins, to evade immune surveillance and suppress immune activation. Therefore, significant efforts have been made to develop the strategies for stimulating immune responses against cancers. Among these, the use of extracellular vesicles (EVs) to enhance the anti-tumor immune response has emerged as a particularly promising approach in cancer management. EVs possess several unique properties that elevate the potency in modulating immune responses. This review article provides a comprehensive overview of recent advances in this field, focusing on the strategic usage of EVs to overcome tumor-induced immune tolerance. We discuss the biogenesis and characteristics of EVs, as well as their potential applications in medical contexts. The immune mechanisms within the tumor microenvironment and the strategies employed by cancers to evade immune detection are explored. The roles of EVs in regulating the tumor microenvironment and enhancing immune responses for immunotherapy are also highlighted. Additionally, this article addresses the challenges and future directions for the development of EV-based nanomedicine approaches, aiming to improve cancer immunotherapy outcomes with greater precision and efficacy while minimizing off-target effects.

Engineering the physical characteristics of biomaterials for innate immune-mediated cancer immunotherapy

It has recently been recognized that the physical characteristics of biomaterials - such as size, structure, shape, charge, mechanical strength, hydrophobicity, and multivalency - regulate immunological functions in innate immune cells. In immuno-oncology applications, biomaterials are engineered with distinct physical properties to achieve desired innate immune responses. In this review, we discuss how physical characteristics influence effector functions and innate immune signaling pathways in distinct innate immune cell subtypes. We highlight how physical properties of biomaterials impact phagocytosis regulation, biodistribution, and innate immune cell targeting. We outline the recent advances in physical engineering of biomaterials that directly or indirectly induce desired innate immune responses for cancer immunotherapy. Lastly, we discuss the challenges in current biomaterial approaches that need to be addressed to improve clinical applicability.

Harnessing nanoparticles for reshaping tumor immune microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers, characterized by high morbidity and mortality rates. Recently, immunotherapy has emerged as a crucial treatment modality for HCC, following surgery, locoregional therapies, and targeted therapies. This approach harnesses the body's immune system to target and eliminate cancer cells, potentially resulting in durable antitumor responses. However, acquired resistance and the tumor immunosuppressive microenvironment (TIME) significantly hinder its clinical application. Recently, advancements in nanotechnology, coupled with a deeper understanding of cancer biology and nano-biological interactions, have led to the development of various nanoparticles aimed at enhancing therapeutic efficacy through specific targeting of tumor tissues. These nanoparticles increase the accumulation of immunotherapeutic drugs within the tumor microenvironment, thereby transforming the TIME. In this review, we provide a concise overview of the fundamental principles governing the TIME landscape in HCC and discuss the rationale for and applications of nanoparticles in this context. Additionally, we highlight existing challenges and potential opportunities for the clinical translation of cancer nanomedicines.

The impact of cytokines and tumour-conditioned medium on the properties of murine in vitro generated myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immature myeloid cells playing a critical role in immune suppression. In vitro-generated MDSCs are a convenient tool to study the properties of tumour-associated MDSCs. Here, we compared six protocols for in vitro generation of functional mouse MDSCs from bone marrow progenitors. The protocols included granulocyte-macrophage colony-stimulating factor (GM-CSF) alone or in combination with interleukin-6 (IL-6) or granulocyte colony-stimulating factor (G-CSF), with or without a tumour-conditioned medium (TCM) derived from B16-F10 melanoma. Obtained MDSCs were characterized by morphology, phenotype, gene expression of key immunosuppressive factors, and in vitro suppression of T cell proliferation. All tested protocols yielded approximately 25% monocytic and 50% polymorphonuclear MDSCs. Protocols using IL-6 generated MDSCs with reduced maturation and differentiation status, upregulated Arg1 and Nos1 mRNA expression, increased levels of Arg-1 and TGF-β proteins and enhanced ROS production compared to the other protocols. All tested protocols yielded MDSCs that efficiently inhibited T cell proliferation in vitro, with some advantage for the GM-CSF and G-CSF + GM-CSF protocols. Interestingly, a combination of protocols with B16-F10-derived TCM resulted in the generation of MDSCs with reduced immunosuppressive properties. Our results provide valuable insights into the optimal conditions for in vitro generation of MDSCs with specific immunosuppressive properties.

Bone marrow-derived dendritic cells play a role in attenuating inflammation on Bothrops jararacussu venom muscle damage

The immune system is regulated by dendritic cells (DCs), which are highly specialized cells for presenting antigens. They are thought of as natural sentinels that start the immune response triggered by naive T cells against invasive infections. DCs participate in the initial stage of muscle damage in conjunction with monocytes, macrophages, and myogenic cells. The goal of this study was to determine whether DCs might mitigate tissue damage and aid in the regeneration of the gastrocnemius muscle following envenomation with Bothrops jararacussu venom (BjV). Mature bone marrow dendritic cells (BMDCs) were used to treat mice in an experimental envenomation model with BjV by activation with lipopolysaccharide (LPS). BMDCs were injected into the gastrocnemius muscle at the same site of the BjV injury, in a single dose, 3 h after envenomation, and envenoming effects were observed at different periods for 7 days. In both untreated (NT) and treated (T) groups tissue necrosis, leukocyte influx, and hemorrhage at the injury site were observed. Results showed an increase in serum and tissue CK as well as IL-6, TNF-α, and IL-1β release in the first hours after envenoming. In contrast, after treatment with BMDCs results obtained demonstrated an attenuated local effect with a small leukocyte influx, decreased or non-existent necrosis and hemorrhage, as well as a reduction in both serum and tissue CK levels as well as cytokine release and, consequently, the onset of a moderate regenerative process. The present study's findings concluded that BjV causes a severe inflammatory reaction at the site of injury and that treating envenoming with BMDCs in the muscle was crucial for minimizing damage to the muscle and the inflammatory reaction and promoting the early onset of the tissue repair process.

Dendritic cells immunotargeted therapy for atherosclerosis

Atherosclerosis, a chronic inflammatory disease, is markedly influenced by both immune and inflammatory reactions throughout its progression. Dendritic cells, as pivotal antigen-presenting entities, play a crucial role in the initiation of immune responses and the preservation of immunological homeostasis. Accumulating data indicates that dendritic cells are present in healthy arteries and accumulate significantly in atherosclerotic plaques. Novel immunotherapeutic approaches and vaccination protocols have yielded substantial clinical advancements in managing chronic inflammatory diseases, with dendritic cell-centric modalities emerging for atherosclerotic management. In this review, we delineate the essential functions and underlying mechanisms of dendritic cells and their subsets in the modulation of atherosclerotic inflammation and immune responses. We underscore the immense promise of dendritic cell-based immunotherapeutic strategies, including vaccines and innovative combinations with nanotechnological drug delivery platforms for atherosclerosis treatment. We also discuss the challenges associated with dendritic cell immunotherapy and provide perspectives on the future direction of this field.

Evolution of the ocular immune system

The evolution of the ocular immune system should be viewed within the context of the evolution of the immune system, and indeed organisms, as a whole. Since the earliest time, the most primitive responses of single cell organisms involved molecules such as anti-microbial peptides and behaviours such as phagocytosis. Innate immunity took shape ~2.5 billion years ago while adaptive immunity and antigen specificity appeared with vertebrate evolution ~ 500 million years ago. The invention of the microscope and the germ theory of disease precipitated debate on cellular versus humoral immunity, resolved by the discovery of B and T cells. Most recently, our understanding of the microbiome and consideration of the host existing symbiotically with trillions of microbial genes (the holobiont), suggests that the immune system is a sensor of homoeostasis rather than simply a responder to pathogens. Each tissue type in multicellular organisms, such as vertebrates, has a customised response to immune challenge, with powerful reactions most evident in barrier tissues such as the skin and gut mucosa, while the eye and brain occupy the opposite extreme where responses are attenuated. The experimental background which historically led to the concept of immune privilege is discussed in this review; however, we propose that the ocular immune response should not be viewed as unique but simply an example of how the tissues variably respond in nature, more or less to the same challenge (or danger).

Overview of dendritic cells subsets and their involvement in immune-related pathological disease

Dendritic cells (DCs) are specialized antigen-presenting cells (APCs) in linking innate and adaptive immune responses. In addition to presenting antigens to T cells, DCs must also provide co-stimulatory signals along with cytokines for T cells to induce an appropriate cellular immune response. Tolerance is also established and maintained by DCs under homeostatic circumstances. There is remarkable phenotypic heterogeneity in DCs, each with different functional flexibility and specific expression of various markers. The three primary categories of DCs comprise conventional DCs (cDCs), plasmacytoid DCs (pDCs), and monocyte-derived DCs (moDCs). Langerhans cells (LCs) are another type of DCs, which are found in the skin's epidermal layer. DCs may be positioned or triggered inappropriately as a result of dysregulation of DC. This phenomenon can cause an imbalance in immune responses and even immune-related pathological disorders, i.e., autoimmune diseases and malignancies. Herein, by reviewing the ontogeny, biology, characteristics, and function of DCs subsets in immune system, we discuss the contribution of these cells in the mentioned immune-related disorders.

Developing T Cell Epitope-Based Vaccines Against Infection: Challenging but Worthwhile

T cell epitope-based vaccines are designed to elicit long-lived pathogen-specific memory T cells that can quickly activate protective effector functions in response to subsequent infections. These vaccines have the potential to provide sustained protection against mutated variants, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which are increasingly capable of evading neutralizing antibodies. Recent advancements in epitope discovery, T cell receptor analysis, and bioinformatics have enabled the precise selection of epitopes and the sophisticated design of epitope-based vaccines. This review outlines the development process for T cell epitope-based vaccines. We summarize the current progress in T cell epitope discovery technologies, highlighting the advantages and disadvantages of each method. We also examine advancements in the design and optimization of epitope-based vaccines, particularly through bioinformatics tools. Additionally, we discuss the challenges of validating the accurate processing and presentation of individual epitopes and establishing suitable rodent models to evaluate vaccine immunogenicity and protective efficacy.

Combinational delivery of TLR4 and TLR7/8 agonist enhanced the therapeutic efficacy of immune checkpoint inhibitors to colon tumor

Immunotherapy is regarded as a potent cancer treatment, with DC vaccines playing a crucial role. Although clinical trials have demonstrated the safety and efficacy of DC vaccines, loading antigens in vitro is challenging, and their therapeutic effects remain unpredictable. Moreover, the diverse subtypes and maturity states of DCs in the body could induce both immune responses and immune tolerance, potentially affecting the vaccine's efficacy. Hence, the optimization of DC vaccines remains imperative. Our study discovered a new therapeutic strategy by using CT26 and MC38 mouse colon cancer models, as well as LLC mouse lung cancer models. The strategy involved the synergistic activation of DCs through intertumoral administration of TLR4 agonist high-mobility group nucleosome binding protein 1 (HMGN1) and TLR7/8 agonist (R848/resiquimod), combined with intraperitoneal administration of TNFR2 immunosuppressant antibody. The experimental results indicated that the combined use of HMGN1, R848, and α-TNFR2 had no effect on LLC cold tumors. However, it was effective in eradicating CT26 and MC38 colon cancer and inducing long-term immune memory. The combination of these three drugs altered the TME and promoted an increase in anti-tumor immune components. This may provide a promising new treatment strategy for colon cancer.

Immunomodulatory Effects of Vitamin D and Zinc on Viral Infection

Several nutrients are crucial in enhancing the immune system and preserving the structural integrity of bodily tissue barriers. Vitamin D (VD) and zinc (Zn) have received considerable interest due to their immunomodulatory properties and ability to enhance the body's immune defenses. Due to their antiviral, anti-inflammatory, antioxidative, and immunomodulatory properties, the two nutritional powerhouses VD and Zn are crucial for innate and adaptive immunity. As observed with COVID-19, deficiencies in these micronutrients impair immune responses, increasing susceptibility to viral infections and severe disease. Ensuring an adequate intake of VD and Zn emerges as a promising strategy for fortifying the immune system. Ongoing clinical trials are actively investigating their potential therapeutic advantages. Beyond the immediate context of the pandemic, these micronutrients offer valuable tools for enhancing immunity and overall well-being, especially in the face of future viral threats. This analysis emphasizes the enduring significance of VD and Zn as both treatment and preventive measures against potential viral challenges beyond the current health crisis. The overview delves into the immunomodulatory potential of VD and Zn in combating viral infections, with particular attention to their effects on animals. It provides a comprehensive summary of current research findings regarding their individual and synergistic impacts on immune function, underlining their potential in treating and preventing viral infections. Overall, this overview underscores the need for further research to understand how VD and Zn can modulate the immune response in combatting viral diseases in animals.

Guidelines for preparation and flow cytometry analysis of human nonlymphoid tissue DC

This article is part of the Dendritic Cell Guidelines article series, which provides a collection of state-of-the-art protocols for the preparation, phenotype analysis by flow cytometry, generation, fluorescence microscopy, and functional characterization of mouse and human dendritic cells (DC) from lymphoid organs, and various nonlymphoid tissues. Within this article, detailed protocols are presented that allow for the generation of single-cell suspensions from human nonlymphoid tissues including lung, skin, gingiva, intestine as well as from tumors and tumor-draining lymph nodes with a subsequent analysis of dendritic cells by flow cytometry. Further, prepared single-cell suspensions can be subjected to other applications including cellular enrichment procedures, RNA sequencing, functional assays, etc. While all protocols were written by experienced scientists who routinely use them in their work, this article was also peer-reviewed by leading experts and approved by all co-authors, making it an essential resource for basic and clinical DC immunologists.

Arabinogalactan from Cynanchum atratum induces tolerogenic dendritic cells in gut to restrain autoimmune response and alleviate collagen-induced arthritis in mice

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease characterized by multiple joints lesions. Tolerogenic dendritic cells (tolDCs) play crucial roles in maintaining immune homeostasis. The immunomodulatory activity of plant-derived arabinogalactan (AGs) has been well investigated, however, whether AGs could suppress autoimmune responses by inducing tolDCs is remain unclear.

DESIGN

Collagen-induced arthritis (CIA, a mouse model of RA) mice were utilized to ascertain the role of AGs (obtained from Cynanchum atratum) in autoimmune responses. An antibiotic cocktail was administered to eliminate gut microbiota. Germ-free (GF) and Toll-like receptor 2 (TLR2) knockout mice were used to determine the function of AGs in intestinal immune cells.

RESULTS

The oral administration of dietary AGs substantially reduced the severity of CIA and rebalanced the ratio of regulatory T cells (Tregs) to T helper 17 (Th17) cells. Although the antibiotic cocktail depleted the mice's gut microbiota, AGs had a therapeutic effect on their CIA. AGs restored Treg/Th17 homeostasis by inducing CD103+ tolDCs, regardless of the gut microbiota of the GF mice. Coculture experiments confirmed that AGs induced tolDCs and transforming growth factor β (TGF-β) secretion, leading to Treg amplification. RNA sequencing and TLR2 knockout experiments revealed that AGs induced tolDCs through a TLR2-mediated mechanism. Preventive interventions with AGs established a tolerogenic intestinal immune microenvironment, which delayed the onset and progression of CIA. AGs functioned synergistically with tofacitinib, a JAK inhibitor, to effectively restore Treg/Th17 balance and alleviate CIA.

CONCLUSION

This study introduces a novel microbiota-independent mechanism through which soluble dietary AGs inhibit systemic autoimmune responses. Our findings provide insights into the supplementation of dietary AGs in patients with preclinical or progressive RA.

The correlation between immune cells and endometriosis: a bidirectional two-sample mendelian randomization study

OBJECTIVES

Endometriosis (EM), a prevalent estrogen-dependent inflammatory disorder affecting women of reproductive age, is characterized by the presence of endometrial-like tissue outside the uterus, resulting in pelvic scarring, pain, and infertility. Although the pathogenesis of EM remains poorly understood, there is growing evidence suggesting the involvement of the immune system in its etiology, pathophysiology, and associated morbidities such as pain, infertility, and adverse pregnancy outcomes. While previous studies have indicated a close relationship between the immune system and EM, the specific underlying mechanism remains incompletely elucidated.

METHODS

Through the utilization of publicly available genetic data, a two-sample Mendelian randomization (MR) analysis was conducted to establish an association between 731 immune cell phenotypes and EM. Comprehensive sensitivity analyses were performed to validate the robustness, heterogeneity, and potential horizontal pleiotropy of the findings.

RESULTS

The MR analysis revealed potential associations between 22 immune cell phenotypes and EM. Conversely, reverse MR analysis identified 11 immune phenotypes demonstrating potential associations between genetic liability in the immune phenotypes and EM.

CONCLUSION

This study provides evidence of a potential correlation between immune cell phenotypes and EM, including the existence of reverse causation. These findings open up new avenues for investigating the underlying mechanisms of EM.

Dynamic Diselenide Hydrogels for Controlled Tumor Organoid Culture and Dendritic Cell Vaccination

Dynamic hydrogels are emerging as advanced materials for engineering tissue-like environments that mimic cellular microenvironments. We introduce a diselenide-cross-linked hydrogel system with light-responsive properties, designed for precise control of tumor organoid growth and light-initiated radical inactivation, particularly for dendritic cell (DC) vaccines. Diselenide exchange enables stress relaxation and hydrogel remodeling, while recombination and quenching of seleno radicals (Se•) reduce cross-linking density, leading to controlled degradation. We demonstrate a 2D to 3D growth strategy, where tumor cells inoculate on the hydrogel surface, expand, and gradually form spherical organoids within the 3D hydrogel. These tumor organoids show significantly higher drug resistance compared to 2D-cultured cells. High-density light irradiation enhances diselenide exchange, inducing hydrogel degradation, tumor cell death, and release of functional antigens. This system serves as a dynamic platform for tumor organoid culture and antigen release, offering significantly advanced approaches for in vitro tumor modeling and immunological research. Our findings position diselenide-cross-linked hydrogels as versatile materials for precision cellular engineering, with broad applications in cancer research and beyond.

Bothrops atrox snake venom decreased MHC-II and CD86 expression in bone marrow-derived dendritic cells

The effect of Bothrops atrox venom (BaV) on the maturation of bone marrow-derived dendritic cells (BMDCs) from mice was investigated, with a focus on selected cell markers, TAP1 expression, and the release of pro-inflammatory cytokines during this process. The objective was to evaluate BaV's impact on dendritic cell (DC) function, as DCs are pivotal in antigen presentation and responsible for initiating the immune response mediated by naïve T cells, as well as regulating the immune system. Bone marrow cells were obtained from Swiss mice, and hematopoietic precursors were differentiated into BMDCs using GM-CSF and IL-4. On the 7th day, BaV and LPS were introduced into the culture, and the cells were analyzed 24 h later. BaV's ability to stimulate BMDC maturation was assessed through the analysis of surface marker expression. The findings demonstrated that BMDCs are highly influenced by culture environment factors, such as GM-CSF and IL-4, and are sensitive to additional stimuli like LPS and BaV. Mature DCs exhibited elevated levels of critical markers for T cell activation, such as MHC-II, CD80, and CD86, displaying specific phenotypic characteristics. However, the observed reduction in MHC-II and CD86 expression following BaV exposure suggests a substantial impact on the immunological activation capacity of these cells, potentially interfering with the adaptive immune response. Furthermore, the selective release of cytokines, such as IL-6, but not TNF-α or IL-1β, indicates differentiated modulation of inflammatory responses by DCs under various stimulation conditions.

Metal-ion-chelating phenylalanine nanostructures reverse immune dysfunction and sensitize breast tumour to immune checkpoint blockade

An immunosuppressive tumour microenvironment strongly influences response rates in patients receiving immune checkpoint blockade-based cancer immunotherapies, such as programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1). Here we demonstrate that metal-ion-chelating L-phenylalanine nanostructures synergize with short-term starvation (STS) to remodel the immunosuppressive microenvironment of breast and colorectal tumours. These nanostructures modulate the electrophysiological behaviour of dendritic cells and activate them through the NLRP3 inflammasome and calcium-mediated nuclear factor-κB pathway. STS promotes the cellular uptake of nanostructures through amino acid transporters and plays a key role in dendritic cell maturation and tumour-specific cytotoxic T lymphocyte responses. This study demonstrates the potential role of metal-ion-chelating L-phenylalanine nanostructures in activating immune responses and the effect of STS treatment in improving nanomaterial-mediated cancer immunotherapy.

Cistanche deserticola polysaccharide-functionalized dendritic fibrous nano-silica as oral delivery system for H9N2 vaccine to promote systemic and mucosal immune response

Most infectious diseases are caused by pathogens that invade the body tissues through mucosal tract. Therefore, it is essential to develop effective vaccines administered through the mucosa as a first-line of defense against major infectious diseases. Oral delivery of vaccines is currently of great interest due to its potential to elicit both mucosal and systemic immune responses, high compliance rate and non-invasive nature. However, their development is limited by the challenging gastrointestinal (GI) environment, the low permeability of the mucus barrier, and the lack of effective and safe mucosal adjuvants. Currently, nanoparticle-based strategies show significant potential for improving oral vaccine delivery systems. Herein, the dendritic fibrous nano-silica (DFNS) grafted with Cistanche deserticola polysaccharide (CDP) nanoparticles (CDP-DFNS) were developed for oral delivery of H9N2 antigen. CDP-DFNS induced the activation of macrophages, thereby enhancing antigen uptake in vitro. Additionally, CDP-DFNS/H9N2 significantly activated the dendritic cells (DCs) in Peyer's patches (PPs), and T/B cells in mesenteric lymph nodes (MLNs). Moreover, CDP-DFNS/H9N2 enhanced the HI titers and levels of H9N2-specific antibody IgG, secretory IgA (SIgA) and H9N2-specific IgA in intestinal and respiratory mucosa, as well as Th-associated cytokines. Our results indicate that CDP-DFNS could be a promising oral vaccine adjuvant delivery system.

Omonijo F, A Ganai N, M. Ibeagha-Awemu E, Mudasir Ahmad S. Immunotherapy in mastitis: state of knowledge, research gaps and way forward

Mastitis is an inflammatory condition that affects dairy cow's mammary glands. Traditional treatment approaches with antibiotics are increasingly leading to challenging scenarios such as antimicrobial resistance. In order to mitigate the unwanted side effects of antibiotics, alternative strategies such as those that harness the host immune system response, also known as immunotherapy, have been implemented. Immunotherapy approaches to treat bovine mastitis aims to enhance the cow's immune response against pathogens by promoting pathogen clearance, and facilitating tissue repair. Various studies have demonstrated the potential of immunotherapy for reducing the incidence, duration and severity of mastitis. Nevertheless, majority of reported therapies are lacking in specificity hampering their broad application to treat mastitis. Meanwhile, advancements in mastitis immunotherapy hold great promise for the dairy industry, with potential to provide effective and sustainable alternatives to traditional antibiotic-based approaches. This review synthesizes immunotherapy strategies, their current understanding and potential future perspectives. The future perspectives should focus on the development of precision immunotherapies tailored to address individual pathogens/group of pathogens, development of combination therapies to address antimicrobial resistance, and the integration of nano- and omics technologies. By addressing research gaps, the field of mastitis immunotherapy can make significant strides in the control, treatment and prevention of mastitis, ultimately benefiting both animal and human health/welfare, and environment health.

Diverse roles of dendritic cell and regulatory T cell crosstalk in controlling health and disease

Dendritic cells (DCs) are specialized antigen-presenting cells for lymphocytes, including regulatory T (Treg) cells, a subset of CD4+ T cells expressing CD25 and Foxp3, a transcription factor. Treg cells maintain immunological self-tolerance in mice and humans, and suppress autoimmunity and other various immune responses such as tumor immunity, transplant rejection, allergy, responses to microbes, and inflammation. Treg-cell proliferation is controlled by antigen-presenting DCs. On the other hand, Treg cells suppress the function of DCs by restraining DC maturation. Therefore, the interaction between DCs and Treg cells, DC-Treg crosstalk, could contribute to controlling health and disease. We recently found that unique DC-Treg crosstalk plays a role in several conditions. First, Treg cells are expanded in ultraviolet B (UVB)-exposed skin by interacting with DCs, and the UVB-expanded Treg cells have a healing function. Second, manipulating DC-Treg crosstalk can induce effective acquired immune responses against severe acute respiratory syndrome coronavirus 2 antigens without adjuvants. Third, Treg cells with a special feature interact with DCs in the tumor microenvironment of human head and neck cancer, which may contribute to the prognosis. Understanding the underlying mechanisms of DC-Treg crosstalk may provide a novel strategy to control health and disease.

Understanding the role of biomolecular coronas in human exposure to nanomaterials

Nanomaterials (NMs) are increasingly used in medical treatments, electronics, and food additives. However, nanosafety-the possible adverse effects of NMs on human health-is an area of active research. This review provides an overview of the influence of biomolecular coronas on NM transformation following various exposure routes. We discuss potential exposure pathways, including inhalation and ingestion, describing the physiology of exposure routes and emphasising the relevance of coronas in these environments. Additionally, we review other routes to NM exposure, such as synovial fluid, blood (translocation and injection), dermal and ocular exposure, as well as the dose and medium impact on NM interactions. We emphasize the need for an in-depth characterisation of coronas in different biological media, highlighting the need and opportunity to study lung and gastric fluids to understand NM behaviour and potential toxicity. Future research aims to predict better in vivo outcomes and address the complexities of NM interactions with biological systems.

Modified PEG-Lipids Enhance the Nasal Mucosal Immune Capacity of Lipid Nanoparticle mRNA Vaccines

BACKGROUND/OBJECTIVES

Omicron, the predominant variant of SARS-CoV-2, exhibits strong immune-evasive properties, leading to the reduced efficacy of existing vaccines. Consequently, the development of versatile vaccines is imperative. Intranasal mRNA vaccines offer convenient administration and have the potential to enhance mucosal immunity. However, delivering vaccines via the nasal mucosa requires overcoming complex physiological barriers. The aim of this study is to modify PEGylated lipids to enhance the mucosal immune efficacy of the vaccine.

METHODS

The PEGylated lipid component of lipid nanoparticle (LNP) delivery vectors was modified with chitosan or mannose to generate novel LNPs that enhance vaccine adhesion or targeting on mucosal surfaces. The impact of the mRNA encoding the receptor-binding domain of Omicron BA.4/BA.5 on the immune response was examined.

RESULTS

Compared to the unmodified LNP group, the IgG and IgA titers in the chitosan or mannose-modified LNP groups showed an increasing trend. The chitosan-modified group showed better effects. Notably, the PEGylated lipid with 1.5 mol% of chitosan modification produced high levels of IgG1 and IgG2a antibodies, promoting Th1/Th2 responses while also generating high levels of IgA, which can induce stronger cellular immunity, humoral immunity, and mucosal immunity.

CONCLUSIONS

The 1.5 mol% of chitosan-modified LNPs (mRNA-LNP-1.5CS) can serve as a safe and effective carrier for intranasal mRNA vaccines, offering a promising strategy for combating the Omicron variant.

Dendritic cell maturation is induced by p53-armed oncolytic adenovirus via tumor-derived exosomes enhancing systemic antitumor immunity

Dendritic cells (DCs) are crucial in cancer immunity, because they activate cytotoxic T cells by presenting tumor antigens. Recently, oncolytic virus therapy has been recognized as a systemic immune stimulator. We previously developed a telomerase-specific oncolytic adenovirus (OBP-301) and a p53-armed OBP-301 (OBP-702), demonstrating that these viruses strongly activate systemic antitumor immunity. However, their effects on DCs remained unclear. In the present study, the aim was to elucidate the mechanisms of DC activation by OBP-702, focusing particularly on tumor-derived exosomes. Exosomes (Exo53, Exo301, or Exo702) were isolated from conditioned media of human or murine pancreatic cancer cell lines (Panc-1, MiaPaCa-2, and PAN02) after treatment with Ad-p53, OBP-301, or OBP-702. Exo702 derived from Panc-1 and MiaPaCa-2 cells significantly upregulated CD86, CD80, CD83 (markers of DC maturation), and IFN-γ in DCs in vitro. Similarly, Exo702 derived from PAN02 cells upregulated CD86 and IFN-γ in bone marrow-derived DCs in a bilateral PAN02 subcutaneous tumor model. This DC maturation was inhibited by GW4869, an inhibitor of exosome release, and anti-CD63, an antibody targeting the exosome marker. Intratumoral injection of OBP-702 into PAN02 subcutaneous tumors significantly increased the presence of mature DCs and CD8-positive T cells in draining lymph nodes, leading to long-lasting antitumor effects through the durable activation of systemic antitumor immunity. In conclusion, tumor-derived exosomes play a significant role in DC maturation following OBP-702 treatment and are critical for the systemic activation of antitumor immunity, leading to the abscopal effect.

MDM2 inhibitors in cancer immunotherapy: Current status and perspective

Murine double minute 2 (MDM2) plays an essential role in the cell cycle, apoptosis, DNA repair, and oncogene activation through p53-dependent and p53-independent signaling pathways. Several preclinical studies have shown that MDM2 is involved in tumor immune evasion. Therefore, MDM2-based regulation of tumor cell-intrinsic immunoregulation and the immune microenvironment has attracted increasing research attention. In recent years, immune checkpoint inhibitors targeting PD-1/PD-L1 have been widely used in the clinic. However, the effectiveness of a single agent is only approximately 20%-40%, which may be related to primary and secondary drug resistance caused by the dysregulation of oncoproteins. Here, we reviewed the role of MDM2 in regulating the immune microenvironment, tumor immune evasion, and hyperprogression during immunotherapy. In addition, we summarized preclinical and clinical findings on the use of MDM2 inhibitors in combination with immunotherapy in tumors with MDM2 overexpression or amplification. The results reveal that the inhibition of MDM2 could be a promising strategy for enhancing immunotherapy.

Peritoneal Dissemination and Malignant Ascites in Duodenal Cancer Successfully Treated With Adoptive Cell Therapy Using WT1- and MUC1-Pulsed Dendritic Cells and Activated T Cells With No Adverse Effects: A Case Report

A satisfactory treatment for the dissemination of duodenal cancer has not yet been established. We describe a case of peritoneal dissemination and malignant ascites in duodenal cancer that was successfully treated with adoptive cell therapy with no adverse effects. A 72-year-old Japanese male patient with primary duodenal cancer with distal lymph node metastases received chemotherapy with S-1, an oral pyrimidine fluoride-derived agent, and oxaliplatin after gastrojejunal bypass, which resulted in tumor shrinkage; however, peritoneal dissemination developed. Despite the administration of a second-line chemotherapy regimen comprising irinotecan, peritoneal dissemination, malignant ascites, and cachexia continued to progress, ultimately resulting in the failure of chemotherapy. He then received adoptive cell therapy with Wilms' tumor 1 (WT1)- and mucin 1 (MUC1) peptide-pulsed dendritic cells (WT1/MUC1-DC) and CD3-activated T lymphocytes (CAT). Following the administration of this treatment eight times per week, the patient's symptoms and malignant ascites surrounding his cancer disappeared. He developed no adverse effects from this treatment and was able to resume his usual activities without any symptoms. He has continued this treatment every few months as maintenance therapy and has been free of relapse for 54 months. This case suggests a possible beneficial effect of adoptive cell therapy with WT1/MUC1-DC and CAT for peritoneal dissemination and malignant ascites in duodenal cancer.

Farnesyl pyrophosphate potentiates dendritic cell migration in autoimmunity through mitochondrial remodelling

Cellular metabolism modulates dendritic cell (DC) maturation and activation. Migratory dendritic cells (mig-DCs) travelling from the tissues to draining lymph nodes (dLNs) are critical for instructing adaptive immune responses. However, how lipid metabolites influence mig-DCs in autoimmunity remains elusive. Here, we demonstrate that farnesyl pyrophosphate (FPP), an intermediate of the mevalonate pathway, accumulates in mig-DCs derived from mice with systemic lupus erythematosus (SLE). FPP promotes mig-DC survival and germinal centre responses in the dLNs by coordinating protein geranylgeranylation and mitochondrial remodelling. Mechanistically, FPP-dependent RhoA geranylgeranylation promotes mitochondrial fusion and oxidative respiration through mitochondrial RhoA-MFN interaction, which subsequently facilitates the resolution of endoplasmic reticulum stress in mig-DCs. Simvastatin, a chemical inhibitor of the mevalonate pathway, restores mitochondrial function in mig-DCs and ameliorates systemic pathogenesis in SLE mice. Our study reveals a critical role for FPP in dictating mig-DC survival by reprogramming mitochondrial structure and metabolism, providing new insights into the pathogenesis of DC-dependent autoimmune diseases.

Safety and immunogenicity of CD40.HIVRI.Env, a dendritic cell-based HIV vaccine, in healthy HIV-uninfected adults: a first-in-human randomized, placebo-controlled, dose-escalation study (ANRS VRI06)

Background

Current HIV prophylactic vaccines evaluate HIV Env as purified proteins. CD40.HIVRI.Env is an innovative antigen delivery targeting gp140 Env from HIV Clade C 96ZM651 to CD40-expressing antigen-presenting cells, thus harnessing the intrinsic immune-stimulant properties. DNA-HIV-PT123 vaccine encodes 96ZM651 gp140/Gag and 97CN54 Pol/Nef.

Methods

Seventy-two HIV-negative volunteers were enrolled between 05/2021 and 10/2022 in a phase 1 placebo-controlled trial conducted in France and Switzerland (N° EudraCT: 2020-001814-40; NCT04842682). Volunteers were randomized (5:1 active versus placebo) in groups receiving either 0.3, 1.0, or 3.0 mg CD40.HIVRI.Env (Hiltonol® adjuvanted) alone or co-administered with DNA-HIV-PT123 at weeks (W) 0, 4, and 24. Safety and immunogenicity were monitored until W48. The primary safety endpoint was the proportion of participants per dose cohort and randomized arm without any grade 3 or 4 biological (abnormal laboratory values), or clinical local or systemic solicited, or unsolicited adverse events between W0 and W48 considered to be related or possibly related to the investigational products.

Findings

CD40.HIVRI.Env was well tolerated. Env-specific CD4+ T-cells (IL-2+ or IFN-γ+ or TNF+) were detected in all vaccinees from W6 to W26 and persisted until W48 without a dose-response signal or an effect of DNA-HIV-PT123 co-administration. At W26, IgG response rates (RR) against autologous and nine heterologous gp120/gp140 were 89-100% across all groups and 56-100% at W48. RR against 96ZM651gp70V1V2 were high (90-100%) at W6 and W26 in all groups. Tier1A MW965.26 neutralizing antibody (nAb) titres were detectable in 50-100% of vaccinated individuals at W26, with a dose-response signal, while one volunteer developed nAbs against five Tier2 viruses.

Interpretation

CD40.HIVRI.Env alone or administered with DNA-HIV-PT123 was safe and induced early, and sustained anti-Env cellular and V1V2 IgG responses, identified as correlates of protection in the RV144 trial. CD40 targeting Env-based vaccines may be instrumental for inducing protective vaccine responses in prime-boost strategies.

Funding

ANRS Emerging infectious diseases (ANRS MIE); Vaccine Research Institute (VRI).

Cohesin-mediated chromatin remodeling controls the differentiation and function of conventional dendritic cells

The cohesin protein complex extrudes chromatin loops, stopping at CTCF-bound sites, to organize chromosomes into topologically associated domains, yet the biological implications of this process are poorly understood. We show that cohesin is required for the post-mitotic differentiation and function of antigen-presenting dendritic cells (DCs), particularly for antigen cross-presentation and IL-12 secretion by type 1 conventional DCs (cDC1s) in vivo. The chromatin organization of DCs was shaped by cohesin and the DC-specifying transcription factor IRF8, which controlled chromatin looping and chromosome compartmentalization, respectively. Notably, optimal expression of IRF8 itself required CTCF/cohesin-binding sites demarcating the Irf8 gene. During DC activation, cohesin was required for the induction of a subset of genes with distal enhancers. Accordingly, the deletion of CTCF sites flanking the Il12b gene reduced IL-12 production by cDC1s. Our data reveal an essential role of cohesin-mediated chromatin regulation in cell differentiation and function in vivo, and its bi-directional crosstalk with lineage-specifying transcription factors.

Immunology of Stress: A Review Article

Stress significantly impacts the immune system, affecting susceptibility to illness and overall health. This review examines the intricate relationship between stress and the immune system, offering insights having practical implications for health and disease prevention. Stress can significantly trigger molecular and immune modulation, affecting the distribution and trafficking of immune cells in various organs and altering their composition in the blood. The review delves into two key pathways connecting stress and immunity: the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system. Stress activates the neuroendocrine system and triggers microglia in the brain, releasing stress hormones and neurotransmitters that modulate the function and movement of immune cells. Acute stress can temporarily strengthen immunity and promote protection during infection; in contrast, chronic stress dysregulates or inhibits immune functions. Chronic stress causes an increase in cortisol levels through the HPA axis, ultimately suppressing the immune response. Recognizing stress triggers and implementing effective stress management techniques can significantly impact individuals' well-being. This review indicates that immune cells express genes differentially in response to stress, suggesting individual variabilities in the immune response against stress. This underscores the need for a personalized approach to stress management. This review also highlights the potential link between chronic stress and autoimmune disorders and warrants further investigation.

Triple-negative breast cancer-derived exosomes change the immunological features of human monocyte-derived dendritic cells and influence T-cell responses

BACKGROUND

Triple-negative breast cancer (TNBC) exhibits a lower survival rate in comparison to other BC subtypes. Utilizing dendritic cell (DC) vaccines as a form of immunotherapy is becoming a promising new approach to cancer treatment. However, inadequate immunogenicity of tumor antigens leads to unsatisfactory effectiveness of the DC vaccines. Exosomes are the basis for the latest improvements in tumor immunotherapy. This study examined whether TNBC-derived exosomes elicit immunogenicity on the maturation and function of monocyte-derived DCs and the impact of the exosome-treated monocyte-derived DCs (moDCs) on T cell differentiation.

METHODS

exosomes were isolated from MDA-MB-231 TNBC cancer cells and characterized. Monocytes were separated from peripheral blood mononuclear cells and differentiated into DCs. Then, monocyte-derived DCs were treated with TNBC-derived exosomes. Furthermore, the mRNA levels of the genes and cytokines involved in DC maturation and function were examined using qRT-PCR and ELISA assays. We also cocultured TNBC-derived exosome-treated moDCs with T cells and investigated the role of the treatment in T cell differentiation by evaluating the expression of some related genes by qRT-PCR. The concentration of the cytokines secreted from T cells cocultured with exosome-treated moDCs was quantified by the ELISA assays.

RESULTS

Our findings showed that TNBC-derived exosomes induce immunogenicity by enhancing moDCs' maturation and function. In addition, exosome-treated moDCs promote cocultured T-cell expansion by inducing TH1 differentiation through increasing cytokine production.

CONCLUSION

TNBC-derived exosomes could improve vaccine-elicited immunotherapy by inducing an immunogenic response and enhancing the effectiveness of the DC vaccines. However, this needs to be investigated further in future studies.

Monocyte and Macrophage Functions in Oncogenic Viral Infections

Monocytes and macrophages are part of innate immunity and constitute the first line of defense against pathogens. Bone marrow-derived monocytes circulate in the bloodstream for one to three days and then typically migrate into tissues, where they differentiate into macrophages. Circulatory monocytes represent 5% of the nucleated cells in normal adult blood. Following differentiation, macrophages are distributed into various tissues and organs to take residence and maintain body homeostasis. Emerging evidence has highlighted the critical role of monocytes/macrophages in oncogenic viral infections, mainly their crucial functions in viral persistence and disease progression. These findings open opportunities to target innate immunity in the context of oncogenic viruses and to explore their potential as immunotherapies.

Impact of mitochondrial dysfunction on the antitumor effects of immune cells

Mitochondrial dysfunction, a hallmark of immune cell failure, affects the antitumor effects of immune cells through metabolic reprogramming, fission, fusion, biogenesis, and immune checkpoint signal transduction of mitochondria. According to researchers, restoring damaged mitochondrial function can enhance the efficacy of immune cells. Nevertheless, the mechanism of mitochondrial dysfunction in immune cells in patients with cancer is unclear. In this review, we recapitulate the impact of mitochondrial dysfunction on the antitumor effects of T cells, natural killer cells, dendritic cells, and tumor-associated macrophage and propose that targeting mitochondria can provide new strategies for antitumor therapy.

P2 purinergic receptor expression and function in tumor-related immune cells

P2 purinergic receptor expression is dysregulated in multiple cancer subtypes and is associated with worse outcomes. Studies identify roles for P2 purinergic receptors in tumor cells that drive disease aggressiveness. There is also sufficient evidence that P2 purinergic receptor expression within the tumor microenvironment (TME) is critical for disease initiation and progression. Immune cells constitute a significant component of the TME and display both tumorigenic and anti-tumorigenic potential. Studies pre-dating the investigation of P2 purinergic receptors in cancer identify P2 receptor expression on multiple immune cells including macrophages, neutrophils, T-cells, and dendritic cells; all of which are implicated in tumor initiation, tumor promotion, or response to treatment. Herein, we discuss P2 purinergic receptor expression and function in tumor-related immune cells. We provide a rationale for further investigations of P2 purinergic receptors within the TME to better define the mechanistic pathways of inflammation-mediate tumorigenesis and explore P2 purinergic receptors as potential targets for novel immunotherapeutic approaches.

Continuous Treatment with IncobotulinumtoxinA Despite Presence of BoNT/A Neutralizing Antibodies: Immunological Hypothesis and a Case Report

Botulinum Neurotoxin A (BoNT/A) is a bacterial protein that has proven to be a valuable pharmaceutical in therapeutic indications and aesthetic medicine. One major concern is the formation of neutralizing antibodies (nAbs) to the core BoNT/A protein. These can interfere with the therapy, resulting in partial or complete antibody (Ab)-mediated secondary non-response (SNR) or immunoresistance. If titers of nAbs reach a level high enough that all injected BoNT/A molecules are neutralized, immunoresistance occurs. Studies have shown that continuation of treatment of neurology patients who had developed Ab-mediated partial SNR against complexing protein-containing (CPC-) BoNT/A was in some cases successful if patients were switched to complexing protein-free (CPF-) incobotulinumtoxinA (INCO). This seems to contradict the layperson's basic immunological understanding that repeated injection with the same antigen BoNT/A should lead to an increase in antigen-specific antibody titers. As such, we strive to explain how immunological memory works in general, and based on this, we propose a working hypothesis for this paradoxical phenomenon observed in some, but not all, neurology patients with immunoresistance. A critical factor is the presence of potentially immune-stimulatory components in CPC-BoNT/A products that can act as immunologic adjuvants and activate not only naïve, but also memory B lymphocyte responses. Furthermore, we propose that continuous injection of a BoN/TA formulation with low immunogenicity, e.g., INCO, may be a viable option for aesthetic patients with existing nAbs. These concepts are supported by a real-world case example of a patient with immunoresistance whose nAb levels declined with corresponding resumption of clinical response despite regular INCO injections.

The role of S-adenosylhomocysteine hydrolase-like 1 in cancer

This integrative review aims to highlight the importance of investigating the functional role of AHCYL1, also known as IRBIT, in cancer cells. It has recently been suggested that AHCYL1 regulates cell survival/death, stemness capacity, and the host adaptive response to the tumor microenvironment. Despite this knowledge, the role of AHCYL1 in cancer is still controversial, probably due to its ability to interact with multiple factors in a tissue-specific manner. Understanding the mechanisms regulating the functional interplay between the tumor and the tumor microenvironment that controls the expression of AHCYL1 could provide a deeper comprehension of the regulation of tumor development. Addressing how AHCYL1 modulates cellular plasticity processes in a tumoral context is potentially relevant to developing translational approaches in cancer biology.

Engineered Cancer Nanovaccines: A New Frontier in Cancer Therapy

Vaccinations are essential for preventing and treating disease, especially cancer nanovaccines, which have gained considerable interest recently for their strong anti-tumor immune capabilities. Vaccines can prompt the immune system to generate antibodies and activate various immune cells, leading to a response against tumor tissues and reducing the negative effects and recurrence risks of traditional chemotherapy and surgery. To enhance the flexibility and targeting of vaccines, nanovaccines utilize nanotechnology to encapsulate or carry antigens at the nanoscale level, enabling more controlled and precise drug delivery to enhance immune responses. Cancer nanovaccines function by encapsulating tumor-specific antigens or tumor-associated antigens within nanomaterials. The small size of these nanomaterials allows for precise targeting of T cells, dendritic cells, or cancer cells, thereby eliciting a more potent anti-tumor response. In this paper, we focus on the classification of carriers for cancer nanovaccines, the roles of different target cells, and clinically tested cancer nanovaccines, discussing strategies for effectively inducing cytotoxic T lymphocytes responses and optimizing antigen presentation, while also looking ahead to the translational challenges of moving from animal experiments to clinical trials.