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CD4+ T cells recognize peptide antigens presented on class II major histocompatibility complex (MHC-II) molecules to carry out their function. The remarkable diversity of T cell receptor sequences and lack of antigen discovery approaches for MHC-II make profiling the specificities of CD4+ T cells challenging. We have expanded our platform of signaling and antigen-presenting bifunctional receptors to encode MHC-II molecules presenting covalently linked peptides (SABR-IIs) for CD4+ T cell antigen discovery. SABR-IIs can present epitopes to CD4+ T cells and induce signaling upon their recognition, allowing a readable output. Furthermore, the SABR-II design is modular in signaling and deployment to T cells and B cells. Here, we demonstrate that SABR-IIs libraries presenting endogenous and non-contiguous epitopes can be used for antigen discovery in the context of type 1 diabetes. SABR-II libraries provide a rapid, flexible, scalable and versatile approach for de novo identification of CD4+ T cell ligands from single-cell RNA sequencing data using experimental and computational approaches.

Mural cells directly contact macrophages in the dural layer of the meninges to suppress pro-inflammatory phenotypes, including antigen presentation and lymphocyte differentiation. These mechanisms represent new targets for modulating CNS immune surveillance and pathological inflammation (Min et al. 2024. J. Exp. Med.https://doi.org/10.1084/jem.20230326).

Roughly one-half of mice with partial defects in two immune tolerance pathways (AireGW/+Lyn-/- mice) spontaneously develop severe damage to their retinas due to T cell reactivity to Aire-regulated interphotoreceptor retinoid-binding protein (IRBP). Single-cell T cell receptor (TCR) sequencing of CD4+ T cells specific for a predominate epitope of IRBP showed a remarkable diversity of autoantigen-specific TCRs with greater clonal expansions in mice with disease. TCR transgenic mice made with an expanded IRBP-specific TCR (P2.U2) of intermediate affinity exhibited strong but incomplete negative selection of thymocytes. This negative selection was absent in IRBP-/- mice and greatly defective in AireGW/+ mice. Most P2.U2+/- mice and all P2.U.2+/-AireGW/+ mice rapidly developed inflammation of the retina and adjacent uvea (uveitis). Aire-dependent IRBP expression in the thymus also promoted Treg differentiation, but the niche for this fate determination was small, suggesting differences in antigen presentation leading to negative selection vs. thymic Treg differentiation and a stronger role for negative selection in preventing autoimmune disease in the retina.

According to the widely accepted "three Es" model, the host immune system e liminates malignant cell precursors and contains microscopic neoplasms in a dynamic e quilibrium, preventing cancer outgrowth until neoplastic cells acquire genetic or epigenetic alterations that enable immune e scape. This immunoevasive phenotype originates from various mechanisms that can be classified under a novel "three Cs" conceptual framework: (1) c amouflage, which hides cancer cells from immune recognition, (2) c oercion, which directly or indirectly interferes with immune effector cells, and (3) c ytoprotection, which shields malignant cells from immune cytotoxicity. Blocking the ability of neoplastic cells to evade the host immune system is crucial for increasing the efficacy of modern immunotherapy and conventional therapeutic strategies that ultimately activate anticancer immunosurveillance. Here, we review key hallmarks of cancer immune evasion under the "three Cs" framework and discuss promising strategies targeting such immunoevasive mechanisms. Cancer cells often evade the host immune system, challenging the effectiveness of immunotherapy. In this comprehensive review, Galassi et al. summarize key mechanisms of immune evasion within the "three Cs" framework—camouflage, coercion, and cytoprotection—and discuss promising strategies to target these mechanisms for therapeutic purposes. [ABSTRACT FROM AUTHOR]

Biomaterials can act as pro- or anti-inflammatory agents. However, effects of biomaterials crystallinity on immune responses are poorly understood. We demonstrate that the adjuvant-like behaviour of covalent organic framework (COF) biomaterial is dependent on its crystallinity. COF crystallinity is inversely correlated with the activation of mouse and human dendritic cells (DC), but with antigen presentation by mouse DCs only. Amorphous COFs upregulates NFkB, TNF, and RIG-I signalling pathways, as well as the chemotaxis-associated gene Unc5c, when compared to crystalline COFs. Meanwhile, Unc5c inhibition disrupts the correlation between crystallinity and DC activation. Furthermore, COFs with the lowest crystallinity admixed with chicken ovalbumin (OVA) antigen prevent OVA-expressing B16F10 tumour growth in 60% of mice, with this protection associated with the induction of antigen-specific, pro-inflammatory T cell. The lowest crystalline COFs admixed with TRP2 antigen can also prevent non-immunogenic YUMM1.1 tumour growth in 50% of mice. These findings demonstrate that the crystallinity of biomaterials is an important aspect to consider when designing immunotherapy for pro- or anti-inflammatory applications. Effects of biomaterials crystallinity on immune response is poorly understood. Here the authors show that the degree of crystallinity determines adjuvant-like effects of covalent organic framework (COF) biomaterial, with lower crystallinity correlating with better anti-tumour effects in multiple mouse tumour models. [ABSTRACT FROM AUTHOR]

Tumor immune microenvironmental alterations occur early in multiple myeloma (MM) development. In this study, we aim to systematically characterize the tumor immune microenvironment (TME) and the tumor-immune interactions from precursor stages, i.e., monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM), to newly diagnosed MM, comparing these to healthy donors. Using CIBERSORT, mass cytometry (CyTOF), and single-cell RNA sequencing (scRNA-Seq), we examined innate and adaptive immune changes across these stages. We found a decrease in granulocytes in the TME predicts MM outcomes. HLA-DR is reduced in CD16+ monocytes and plasmacytoid dendritic cells, while myeloid dendritic cells show decreased expression of stress and immune-response genes. NK cells and CD8+ T cells shift from a GZMK+ to a GZMB+ cytotoxic phenotype in the TME, with increased inhibitory markers TIM3 and TIGIT. In paired samples, the proportion and gene expression pattern in patient-specific GZMB+CD8+ T cells remain largely unchanged despite MM progression. Our findings provide a comprehensive immune landscape of MM and its precursors, offering insights into therapeutic strategies. Enhancing neutrophil and NK cell cytotoxicity, tumor antigen presentation, and CD8+ T cell versatility in precursor stages may prevent MM progression. [ABSTRACT FROM AUTHOR]

Age is the greatest risk factor for many neurodegenerative diseases, yet immune system aging, a contributor to neurodegeneration, is understudied. Genetic variation in the LRRK2 gene affects risk for both familial and sporadic Parkinson's disease (PD). The leucine-rich repeat kinase 2 (LRRK2) protein is implicated in peripheral immune cell signaling, but the effects of an aging immune system on LRRK2 function remain unclear. We analyzed peritoneal macrophages from R1441C-Lrrk2 knock-in mice and observed a biphasic, age-dependent effect of the R1441C-Lrrk2 mutation on peritoneal macrophage function. We report increases in antigen presentation, anti-inflammatory cytokine production, lysosomal activity, and pathogen uptake in peritoneal macrophages from young (2- to 3-month-old) female R1441C-Lrrk2 mice. Conversely, macrophages from aged (18- to 21-month-old) female R1441C-Lrrk2 mice exhibited decreased antigen presentation after inflammatory insult, decreased lysosomal function, and pathogen uptake, with a concomitant increase in DNA fragmentation in the presence of pathogens. This immune cell exhaustion phenotype was not observed in male R1441C-Lrrk2 mice and was driven by increased LRRK2 protein kinase activity. This phenotype was also observed in human peripheral myeloid cells, with monocyte-derived macrophages from patients with PD who had either the R1441C- or Y1699C-LRRK2 mutation exhibiting decreased pathogen uptake and increased PDL1 expression, consistent with immune cell exhaustion. Our findings that LRRK2 mutations conferred an immunological advantage at a young age but could predispose the carrier to age-acquired immune cell exhaustion have implications for the therapeutic development of LRRK2 inhibitors. Editor's summary: The R1441C mutation in the LRRK2 gene causes a familial form of Parkinson's disease (PD). Wallings et al. now show that this mutation induces a hyperresponsive phenotype in peripheral macrophages from young female mice. This phenotype in young female mice was characterized by increased stimulation-dependent antigen presentation, cytokine release, and phagocytosis. As the female mice aged, they exhibited immune cell exhaustion characterized by peripheral macrophages exhibiting reduced antigen presentation and hypophagocytosis. This immune exhaustion phenotype was also observed in blood monocyte–derived macrophages from patients with PD who carried an R1441C- or Y1699C-LRRK2 mutation. —Orla Smith [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a prevalent form of liver cancer that poses significant challenges regarding morbidity and mortality rates. In the context of HCC, immune cells play a vital role, especially concerning the presentation of antigens. This review explores the intricate interactions among immune cells within HCC, focusing on their functions in antigen presentation and the modulation of T-cell responses. We begin by summarizing the strategies that HCC uses to escape immune recognition, emphasizing the delicate equilibrium between immune surveillance and evasion. Next, we investigate the specific functions of various types of immune cells, including dendritic cells, natural killer (NK) cells, and CD8+ T cells, in the process of antigen presentation. We also examine the impact of immune checkpoints, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and the pathways involving programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1), on antigen presentation, while taking into account the clinical significance of checkpoint inhibitors. The review further emphasizes the importance of immune-based therapies, including cancer vaccines and CAR-T cell therapy, in improving antigen presentation. In conclusion, we encapsulate the latest advancements in research, propose future avenues for exploration, and stress the importance of innovative technologies and customized treatment strategies. By thoroughly analyzing the interactions of immune cells throughout the antigen presentation process in HCC, this review provides an up-to-date perspective on the field, setting the stage for new therapeutic approaches. [ABSTRACT FROM AUTHOR]

Nanoparticles represent a heterogeneous collection of materials, whether natural or synthetic, with dimensions aligning in the nanoscale. Because of their intense manifestation with the immune system, they can be harvested for numerous bio-medical and biotechnological advancements mainly in cancer treatment. This review article aims to scrutinize various types of nanoparticles that interact differently with immune cells like macrophages, dendritic cells, T lymphocytes, and natural killer (NK) cells. It also underscores the importance of knowing how nanoparticles influence immune cell functions, such as the production of cytokines and the presentation of antigens which are crucial for effective cancer immunotherapy. Hence overviews of bio-molecular mechanisms are provided. Nanoparticles can improve antigen presentation, boost T-cell responses, and overcome the immunosuppressive tumor environment. The regulatory mechanisms, signaling pathways, and nanoparticle characteristics are also presented for a comprehensive understanding. We review the nanotechnology platform options and challenges in nanoparticles-based immunotherapy, from an immunotherapy perspective including precise targeting, immune modulation, and potential toxicity, as well as personalized approaches based on individual patient and tumor characteristics. The development of emerging multifunctional nanoparticles and theranostic nanoparticles will provide new solutions for the precision and efficiency of cancer therapies in next-generation practice. [ABSTRACT FROM AUTHOR]

To solve the oxygen dependence problem of photodynamic therapy (PDT), it is critical to explore photosensitizers that do not rely on O2 molecule to generate reactive oxygen species (ROS). Herein, a stable cationic metal‐organic cage [Pd6(RuLoz3)8](BF4)28 (MOC‐88) that possesses high +28 charges is designed. The cage‐confined positive microenvironment enables efficient generation of hydroxyl radicals and improved yield of the singlet oxygen under one‐/two‐photon excitation, showing excellent performance to concurrently enhance Type‐II and O2‐independent‐Type‐I PDT. Moreover, the effective ROS production and robust lipid peroxidation trigger a series of signaling pathways (inflammasome, cyclic guanosine monophosphate–adenosine monophosphate synthase stimulator of interferon genes, and NF‐κB) to evoke PANoptosis and ferroptosis in tumor cells, enabling MOC‐88 to simultaneously cause the loss of cell membrane integrity, release a series of inflammatory cytokines and damage‐associated molecular patterns, stimulate the maturation and antigen presentation ability of dendritic cells, and ultimately activate T‐cell‐dependent adaptive immunity in vivo to inhibit tumor growth. [ABSTRACT FROM AUTHOR]

PA28γ is a proteasomal interactor whose main and most known function is to stimulate the hydrolytic activity of the 20 S proteasome independently of ubiquitin and ATP. Unlike its two paralogues, PA28α and PA28β, PA28γ is largely present in the nuclear compartment and plays pivotal functions in important pathways such as cellular division, apoptosis, neoplastic transformation, chromatin structure and organization, fertility, lipid metabolism, and DNA repair mechanisms. Although it is known that a substantial fraction of PA28γ is found in the cell in a free form (i.e. not associated with 20 S), almost all of the studies so far have focused on its ability to modulate proteasomal enzymatic activities. In this respect, the ability of PA28γ to strongly stimulate degradation of proteins, especially if intrinsically disordered and therefore devoid of three-dimensional tightly folded structure, appears to be the main molecular mechanism underlying its multiple biological effects. Initial studies, conducted more than 20 years ago, came to the conclusion that among the many biological functions of PA28γ, the immunological ones were rather limited and circumscribed. In this review, we focus on recent evidence showing that PA28γ fulfills significant functions in cell-mediated acquired immunity, with a particular role in attenuating MHC class I antigen presentation, especially in relation to neoplastic transformation and autoimmune diseases. [ABSTRACT FROM AUTHOR]

The genetic architecture of multiple sclerosis (MS) is similar to that of coeliac disease, with human leukocyte antigen (HLA) being the greatest genetic determinant in both diseases. Furthermore, similar to the involvement of gluten in coeliac disease, Epstein–Barr virus (EBV) infection is now widely considered to be an important environmental factor in MS. The molecular basis for the HLA association in coeliac disease is well defined, and B cells have a clear role in antigen presentation to gluten-specific CD4+ T cells. By contrast, the mechanisms underlying the HLA association of MS are unknown but accumulating evidence indicates a similar role of B cells acting as antigen-presenting cells. The growing parallels suggest that much could be learned about the mechanisms of MS by using coeliac disease as a model. In this Perspective article, we discuss the insights that could be gained from these parallels and consider the possibility of antiviral treatment against EBV as a therapy for MS that is analogous to the gluten-free diet in coeliac disease. In this Perspective, the authors discuss how our understanding of coeliac disease could provide insights into the mechanisms of multiple sclerosis, the involvement of Epstein–Barr virus and the possibility of antiviral treatment against the virus as a therapy for multiple sclerosis. [ABSTRACT FROM AUTHOR]

Background: Genome instability (GI) is a hallmark of esophageal squamous cell carcinoma (ESCC) while factors affecting GI remain unclear. Methods: Here, we aimed to characterize genomic events representing specific mechanisms of GI based on 201 ESCC samples and validated our findings at the patient, single-cell and cancer cell-line levels, including a newly generated multi-omics dataset of the trial NCT04006041. Results: A two-gene (AHNAK and AHNAK2) mutation signature was identified to define the "AHNAK1/2-mutant" cancer subtype. Single-cell-assisted multi-omics analysis showed that this subtype had a higher neoantigen load, active antigen presentation, and proficient CD8 + T cell infiltrations, which were validated at pan-cancer levels. Mechanistically, AHNAK1/2-mutant ESCC was characterized by impaired response of TGF-β and the inefficient alternative end-join repair (Alt-EJ) that might promote GI. Knockdown of AHNAK in ESCC cell lines resulted in more Alt-EJ events and increased sensitivities to cisplatin. Furthermore, this two-gene signature accurately predicted better responses to DNA-damaging therapy in various clinical settings (HR ≈ 0.25). The two-gene signature predicted higher pCR rates in ESCCs receiving neoadjuvant immunotherapy-involved treatment. Finally, a molecular classification scheme was built and outperformed established molecular typing models in the prognosis stratification of ESCC patients. Conclusion: Our study extended our understanding of the AHNAK family in promoting GI and selecting treatment responders of ESCC. [ABSTRACT FROM AUTHOR]

[Display omitted] • CDs and CMs with good biocompatibility were prepared. • CMB and CMC stimulated the maturation of DC cells and activated T cells. • CMB and CMC can target LNs and induce an immune response to treat primary and distal tumor models. • CMB and CMC can specifically target B16F10 and CT26 tumors, respectively. Although therapeutic nanovaccines have made a mark in cancer immunotherapy, the shortcomings such as poor homing ability of lymph nodes (LNs), low antigen presentation efficiency and low antitumor efficacy have hindered their clinical transformation. Accordingly, we prepared advanced nanovaccines (CMB and CMC) by integrating carbon dots (CDs) with tumor-associated antigens (B16F10 and CT26). These nanovaccines could forwardly target tumors harbouring LNs, induce strong immunogenicity for activating cytotoxic T cells (CTLs), thereby readily eliminating tumor cells and suppressing primary/distal tumor growth. This work provides a promising therapeutic vaccination strategy to enhance cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Messenger RNA (mRNA) vaccines represent a new class of vaccines that has been shown to be highly effective during the COVID‐19 pandemic and that holds great potential for other preventative and therapeutic applications. While it is known that the transcriptional activity of various genes is altered following mRNA vaccination, identifying and studying gene networks could reveal important scientific insights that might inform future vaccine designs. In this study, we conducted an in‐depth weighted gene correlation network analysis of the blood transcriptome before and 24 h after the second and third vaccination with licensed mRNA vaccines against COVID‐19 in humans, following a prime vaccination with either mRNA or ChAdOx1 vaccines. Utilizing this unsupervised gene network analysis approach, we identified distinct modular networks of co‐varying genes characterized by either an expressional up‐ or downregulation in response to vaccination. Downregulated networks were associated with cell metabolic processes and regulation of transcription factors, while upregulated networks were associated with myeloid differentiation, antigen presentation, and antiviral, interferon‐driven pathways. Within this interferon‐associated network, we identified highly connected hub genes such as STAT2 and RIGI and associated upstream transcription factors, potentially playing important regulatory roles in the vaccine‐induced immune response. The expression profile of this network significantly correlated with S1‐specific IgG levels at the follow‐up visit in vaccinated individuals. Those findings could be corroborated in a second, independent cohort of mRNA vaccine recipients. Collectively, results from this modular gene network analysis enhance the understanding of mRNA vaccines from a systems immunology perspective. Influencing specific gene networks could lead to optimized vaccines that elicit augmented vaccine responses. [ABSTRACT FROM AUTHOR]

Melanoma, recognized as one of the most immunogenic malignancies in humans, holds paramount significance in the realm of immunotherapy. However, the emergence of drug resistance and the occurrence of adverse drug reactions underscore the pressing need to explore increasingly personalized immunotherapeutic modalities. Extracellular Vesicles (EVs), pivotal derivatives of immune cells, assume pivotal roles by encapsulating proteins, lipids, and nucleic acids within bilayer lipid structures, thereby facilitating targeted delivery to other immune cells. This orchestrated process orchestrates critical functions including antigen presentation, immune modulation, and the induction of apoptosis in tumor cells. A burgeoning body of evidence underscores the vast therapeutic potential of EVs in melanoma treatment. This comprehensive review aims to delineate the roles of EVs derived from immune cells such as dendritic cells, natural killer cells, macrophages, and T cells in the context of melanoma patients, thereby furnishing invaluable insights for the future direction of melanoma immunotherapy. [ABSTRACT FROM AUTHOR]

Introduction: ER aminopeptidase 1 (ERAP1) is a polymorphic intracellular aminopeptidase with key roles in antigen presentation and adaptive immune responses. ERAP1 allotype 10 is highly protective toward developing some forms of autoimmunity and displays unusual functional properties, including very low activity versus some substrates. Methods: To understand the molecular mechanisms that underlie the biology of allotype 10, we studied its enzymatic and biophysical properties focusing on its unique polymorphisms V349M and Q725R. Results: Compared to ancestral allotype 1, allotype 10 is much less effective in trimming small substrates but presents allosteric kinetics that ameliorate activity differences at high substrate concentrations. Furthermore, it is inhibited by a transition-state analogue via a non-competitive mechanism and is much less responsive to an allosteric small-molecule modulator. It also presents opposite enthalpy, entropy, and heat capacity of activation compared to allotype 1, and its catalytic rate is highly dependent on viscosity. Polymorphisms V349M and Q725R significantly contribute to the lower enzymatic activity of allotype 10 for small substrates, especially at high substrate concentrations, influence the cooperation between the regulatory and active sites, and regulate viscosity dependence, likely by limiting product release. Conclusions: Overall, our results suggest that allotype 10 is not just an inactive variant of ERAP1 but rather carries distinct enzymatic properties that largely stem from changes at positions 349 and 725. These changes affect kinetic and thermodynamic parameters that likely control rate-limiting steps in the catalytic cycle, resulting in an enzyme optimized for sparing small substrates and contributing to the homeostasis of antigenic epitopes in the ER. [ABSTRACT FROM AUTHOR]

Objectives: Despite surgical resection, chemoradiation, and targeted therapy, brain tumors remain a leading cause of cancer-related death in children. Immunotherapy has shown some promise and is actively being investigated for treating childhood brain tumors. However, a critical step in advancing immunotherapy for these patients is to uncover targets that can be effectively translated into therapeutic interventions. Methods: In this study, our team performed a transcriptomic analysis across pediatric brain tumor types to identify potential targets for immunotherapy. Additionally, we assessed components that may impact patient response to immunotherapy, including the expression of genes essential for antigen processing and presentation, inhibitory ligands and receptors, interferon signature, and overall predicted T cell infiltration. Results: We observed distinct expression patterns across tumor types. These included elevated expression of antigen genes and antigen processing machinery in some tumor types while other tumors had elevated inhibitory checkpoint receptors, known to be associated with response to checkpoint inhibitor immunotherapy. Conclusion: These findings suggest that pediatric brain tumors exhibit distinct potential for specific immunotherapies. We believe our findings can guide investigators in their assessment of appropriate immunotherapy classes and targets in pediatric brain tumors. [ABSTRACT FROM AUTHOR]

Historically inflammation against self was considered autoimmune which stems back to the seminal observations by Ehrlich who described serum factors, now known to be autoantibodies produced by B lineage cells that mediate “horror autotoxicus”. The 20th century elucidation of B- and T-cell adaptive immune responses cemented the understanding of the key role of adaptive immune responses in mediating pathology against self. However, Mechnikov shared the Nobel Prize for the discovery of phagocytosis, the most rudimentary aspect of innate immunity. Fast forward some 100 years and an immunogenetic understanding of innate immunity led to the categorising of innate immunopathology under the umbrella term ‘auto inflammation’ and terminology such as “horror autoinflammaticus” to highlight the schism from the classical adaptive immune understanding of autoimmunity. These concepts lead to calls for a two-tiered classification of inflammation against self, but just as innate and adaptive immunity are functionally integrated, so is immunopathology in many settings and the concept of an autoimmune to autoinflammation continuum emerged with overlaps between both. Herein we describe several historically designated disorders of adaptive immunity where innate immunity is key, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) where the immunopathology phenotype is strongly linked to major histocompatibility complex (MHC) class II associations and responds to drugs that target T-cells. We also consider MHC-I-opathies including psoriasis and Behcet's disease(BD) that are increasingly viewed as archetype CD8 T-cell related disorders. We also briefly review the key role of barrier dysfunction in eczema and ulcerative colitis (UC) where innate tissue permeability barrier dysfunction and microbial dysbiosis contributes to prominent adaptive immune pathological mechanisms. We also highlight the emerging roles of intermediate populations of lymphocytes including gamma delta (gd) and mucosal-associated invariant T (MAIT) cells that represent a blend of adaptive immune plasticity and innate immune rapid responders that may also determine site specific patterns of inflammation. [ABSTRACT FROM AUTHOR]

Interleukin-33 (IL-33) is a pleiotropic molecule that plays various roles in the body. However, how exogenous IL-33 changes the tumor immune microenvironment remains unclear. Our study revealed that exogenous IL-33 exerts anti-tumor effects and effectively suppresses the progression of subcutaneous melanoma. scRNA-seq analysis revealed that exogenous IL-33 reduced neutrophils accumulation, thereby improving the inhibitory immune environment. Flow cytometry analysis revealed that exogenous IL-33 significantly increased the proportion of eosinophils and group 2 innate lymphoid cells (ILC2s). In addition, we identified genes encoding major histocompatibility complex (MHC) class II molecules in this group of ILC2s, suggesting that ILC2s may play a role in antigen presentation. In Il7rCreArg1flox/flox mice, the decrease of ILC2s led to a reduction in the proportion of eosinophils. Furthermore, we found that exogenous IL-33 effectively promoted the differentiation of ILC2s and their accumulation in tumors, thereby enhancing the anti-tumor immune response. These findings may pave the way for developing new cancer immunotherapies that use IL-33 as an activator to enhance anti-tumor immune responses. [ABSTRACT FROM AUTHOR]

Plasmodium falciparum infections elicit strong humoral immune responses to two main groups of antigens expressed by blood-stage parasites: merozoite antigens that are involved in the erythrocyte invasion process and variant surface antigens that mediate endothelial sequestration of infected erythrocytes. Long-lived B cells against both antigen classes can be detected in the circulation for years after exposure, but have not been directly compared. Here, we studied the phenotype of long-lived memory and atypical B cells to merozoite antigens (MSP1 and AMA1) and variant surface antigens (the CIDRα1 domain of PfEMP1) in ten Ugandan adults before and after local reduction of P. falciparum transmission. After a median of 1.7 years without P. falciparum infections, the percentage of antigen-specific activated B cells declined, but long-lived antigen-specific B cells were still detectable in all individuals. The majority of MSP1/AMA1-specific B cells were CD95+CD11c+ memory B cells, which are primed for rapid differentiation into antibody-secreting cells, and FcRL5-T-bet- atypical B cells. On the other hand, most CIDRα1-specific B cells were CD95-CD11c- memory B cells. CIDRα1-specific B cells were also enriched among a subset of atypical B cells that seem poised for antigen presentation. These results point to differences in how these antigens are recognized or processed by the immune system and how P. falciparum-specific B cells will respond upon re-infection. Author summary: Immunity to malaria depends in part on memory B cells that rapidly start producing antibodies upon the next infection with the malaria-causing parasite Plasmodium falciparum. Studying memory B cells, in particular long-lived memory B cells, in people living in malaria-endemic regions is difficult, because every P. falciparum infection leads to the activation of existing memory B cells and the formation of new memory B cells. To overcome this problem, we used samples collected from the same people at two time points: (1) during high P. falciparum transmission and (2) following effective mosquito control that resulted in a two-year period without P. falciparum infection. Analyzing antigen-specific B cells from these two time points allowed us to evaluate which P. falciparum-specific B cell subsets remained present in the absence of new infections and could thus be considered long-lived. We found that long-lived memory B cells against erythrocyte invasion antigens expressed the surface markers CD95 and CD11c, while B cells recognizing parasite antigens involved in vascular adhesion and immune evasion did not. These results suggest that the immune response 'sees' and responds to these antigens differently. [ABSTRACT FROM AUTHOR]

Targeted immunotherapies make substantial strides in clinical cancer care due to their ability to counteract the tumor's capacity to suppress immune responses. Advances in biomimetic technology with minimally immunogenic and highly targeted, are addressing issues of targeted drug delivery and disrupting the tumor's immunosuppressive environment to trigger immune activation. Specifically, the use of dendritic cell (DC) membranes to coat nanoparticles ensures targeted delivery due to DC's unique ability to activate naive T cells, spotlighting their role in immunotherapy aimed at disrupting the tumor microenvironment. The potential of DC's biomimetic membrane to mediate immune activation and target tumors is gaining momentum, enhancing the effectiveness of cancer treatments in conjunction with other immune responses. This review delves into the methodologies behind crafting DC membranes and the fusion of dendritic and tumor cell membranes for encapsulating therapeutic nanoparticles. It explores their applications and recent advancements in combating cancer, offering an all-encompassing perspective on DC biomimetic nanosystems, immunotherapy driven by antigen presentation, and the collaborative efforts of drug delivery in chemotherapy and photodynamic therapies. Current evidence shows promise in augmenting combined therapeutic approaches for cancer treatment and holds translational potential for various cancer treatments in a clinical setting. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental Approach Key Results Conclusions and Implications Fulminant myocarditis (FM) is a myocardial inflammatory disease that can result from either viral diseases or autoimmune diseases. In this study, we have determined the treatment effects of immunomodulatory drugs on FM.FM was induced in A/JGpt mice by intraperitoneal administration of coxsackievirus B3, after which immunoglobins were administered daily by intraperitoneal injection. On the seventh day, the cardiac structure and function were determined using echocardiography and cardiac catheterisation. Single‐cell RNA sequencing (scRNA‐seq) was performed to evaluate CD45+ cells in the heart.Immunoglobin, a typical immunomodulatory drug, dramatically reduced mortality and significantly improved cardiac function in mice with FM. ScRNA‐seq revealed that immunoglobin treatment effectively modulated cardiac immune homeostasis, particularly by attenuating overactivated innate immune responses. At the cellular level, immunoglobin predominantly targeted Plac8+ monocytes and S100a8+ neutrophils, suppressing their proinflammatory activities, and enhancing antigen processing and presentation capabilities, thereby amplifying the efficiency and potency of the immune response against the virus. Immunoglobin benefits are mediated by the modulation of multiple signalling pathways, including relevant receptors on immune cells, direction of inflammatory cell chemotaxis, antigen presentation and anti‐viral effects. Subsequently, Bst2-ILT7 ligand‐receptor‐mediated cellular interactions manipulated by immunoglobin were further confirmed in vivo.Immunoglobin treatment significantly attenuated FM‐induced cardiac inflammation and improved cardiac function by inhibiting overactivated innate immune responses. [ABSTRACT FROM AUTHOR]

Macrophages and autophagy are intricately linked, both playing vital roles in maintaining homeostasis and responding to disease. Macrophages, known for their ‘eating’ function, rely on a sophisticated digestion system to process a variety of targets, from apoptotic cells to pathogens. The connection between macrophages and autophagy is established early in their development, influencing both differentiation and mature functions. Autophagy regulates essential immune functions, such as inflammation control, pathogen clearance, and antigen presentation, linking innate and adaptive immunity. Moreover, it modulates cytokine production, ensuring a balanced inflammatory response that prevents excessive tissue damage. Autophagy also plays a critical role in macrophage polarization, influencing their shift between pro‐inflammatory and anti‐inflammatory states. This review explores the role of autophagy in macrophages, emphasizing its impact across various tissues and pathological conditions, and detailing the cellular and molecular mechanisms by which autophagy shapes macrophage function. [ABSTRACT FROM AUTHOR]

Despite the transformative impact of anti-PD-1/PD-L1 therapies, challenges such as low response rates persist. The stimulator of interferon genes (STING) pathway, a crucial element of innate immunity, emerges as a strategic target to overcome these limitations. Understanding its multifaceted functions in cancer, including antigen presentation and response to DNA damage, provides valuable insights. STING agonists, categorized into cyclic dinucleotides (CDNs) and non-CDNs, exhibit promising safety and efficacy profiles. Innovative delivery systems, including antibody-drug conjugates, nanocarriers, and exosome-based therapies, address challenges associated with systemic administration and enhance targeted tumor delivery. Personalized vaccines, such as DT-Exo-STING, showcase the adaptability of STING agonists for individualized treatment. These advancements not only offer new prospects for combination therapies but also pave the way for overcoming resistance mechanisms. This review focuses on the potential of targeting STING pathway to enhance cancer immunotherapy. The integration of STING agonists into cancer immunotherapy holds promise for more effective, personalized, and successful approaches against malignancies, presenting a beacon of hope for the future of cancer treatment. [ABSTRACT FROM AUTHOR]

This review underscores the role of natural products in inducing immunogenic cell death (ICD) as a key strategy in tumor immunotherapy. It reveals that natural products can activate ICD through multiple pathways--apoptosis, autophagy, pyroptosis, and necroptosis--leading to the release of danger-associated molecular patterns (DAMPs), dendritic cell activation, and improved antigen presentation, which together stimulate a potent anti-tumor immune response. The study also demonstrates the enhanced therapeutic potential of combining natural products with immune checkpoint inhibitors. With a focus on translating preclinical findings into clinical practice, this review consolidates recent discoveries and suggests future research paths, offering both theoretical insights and practical guidance for advancing cancer immunotherapy. [ABSTRACT FROM AUTHOR]

In recent years, immunotherapy has developed rapidly as a new field of tumour therapy. However, the efficacy of tumour immunotherapy is not satisfactory due to the immune evasion mechanism of tumour cells, induction of immunosuppressive tumour microenvironment (TME), and reduction of antigen delivery, etc. CRISPR/Cas9 gene editing technology can accurately modify immune and tumour cells in tumours, and improve the efficacy of immunotherapy by targeting immune checkpoint molecules and immune regulatory genes, which has led to the great development and application. In current clinical trials, there are still many obstacles to the application of CRISPR/Cas9 in tumour immunotherapy, such as ensuring the accuracy and safety of gene editing, overcoming overreactive immune responses, and solving the challenges of in vivo drug delivery. Here we provide a systematic review on the application of CRISPR/Cas9 in tumour therapy to address the above existing problems. We focus on CRISPR/Cas9 screening and identification of immunomodulatory genes, targeting of immune checkpoint molecules, manipulation of immunomodulators, enhancement of tumour-specific antigen presentation and modulation of immune cell function. Second, we also highlight preclinical studies of CRISPR/Cas9 in animal models and various delivery systems, and evaluate the efficacy and safety of CRISPR/Cas9 technology in tumour immunotherapy. Finally, potential synergistic approaches for combining CRISPR/Cas9 knockdown with other immunotherapies are presented. This study underscores the transformative potential of CRISPR/Cas9 to reshape the landscape of tumour immunotherapy and provide insights into novel therapeutic strategies for cancer patients. [ABSTRACT FROM AUTHOR]

Major histocompatibility complex class II (MHC-II) is the most significant genetic risk factor for systemic lupus erythematosus (SLE), but the nature of the self-antigens that trigger autoimmunity remains unclear. Unusual self-antigens, termed neoself-antigens, are presented on MHC-II in the absence of the invariant chain essential for peptide presentation. Here, we demonstrate that neoself-antigens are the primary target for autoreactive T cells clonally expanded in SLE. When neoself-antigen presentation was induced by deleting the invariant chain in adult mice, neoself-reactive T cells were clonally expanded, leading to the development of lupus-like disease. Furthermore, we found that neoself-reactive CD4+ T cells were significantly expanded in SLE patients. A high frequency of Epstein-Barr virus reactivation is a risk factor for SLE. Neoself-reactive lupus T cells were activated by Epstein-Barr-virus-reactivated cells through downregulation of the invariant chain. Together, our findings imply that neoself-antigen presentation by MHC-II plays a crucial role in the pathogenesis of SLE. [Display omitted] • Neoself-antigens are presented on MHC-II at low levels of the invariant chain • Lupus-like disease developed upon deletion of the invariant chain from adult mice • Clonal expansion of neoself-reactive T cells was found in SLE patients • Epstein-Barr virus reactivation is one of the factors for neoself-antigen presentation The discrimination of self- and neoself-antigens by T cells plays a crucial role in the activation of autoreactive T cells, leading to the development of autoimmunity. The reactivation of the Epstein-Barr virus is a possible factor that causes MHC class II molecules to present neoself-antigens by decreasing the expression of the invariant chain. [ABSTRACT FROM AUTHOR]

Advances in mass spectrometry accelerates the characterization of HLA ligandome, necessitating the development of efficient methods for immunopeptidomics analysis and (neo)antigen prediction. We develop ImmuneApp, an interpretable deep learning framework trained on extensive HLA ligand datasets, which improves the prediction of HLA-I epitopes, prioritizes neoepitopes, and enhances immunopeptidomics deconvolution. ImmuneApp extracts informative embeddings and identifies key residues for pHLA binding. We also present a more accurate model-based deconvolution approach and systematically analyzed 216 multi-allelic immunopeptidomics samples, identifying 835,551 ligands restricted to over 100 HLA-I alleles. Our investigation reveals the effectiveness of the composite model, denoted as ImmuneApp-MA, which integrates mono- and multi-allelic data to enhance predictive performance. Leveraging ImmuneApp-MA as a pre-trained model, we built ImmuneApp-Neo, an immunogenicity predictor that outperforms existing methods for prioritizing immunogenic neoepitope. ImmuneApp demonstrates its utility across various immunopeptidomics datasets, which will promote the discovery of novel neoantigens and the development of new immunotherapies. The identification of HLA epitopes is essential for vaccine and immunotherapy development. Here, authors develop ImmuneApp using deep learning on extensive immunopeptidomics data, advancing antigen presentation prediction, neoepitope prioritisation, and immunopeptidomics deconvolution. [ABSTRACT FROM AUTHOR]

The field of cancer immunotherapy has seen incredible advancements in the past decades. mRNA-based cancer vaccines generating de novo T cell responses, particularly against tumor-specific antigens (TSAs), have demonstrated promising clinical outcomes and overcome diverse challenges. Despite the high potential of neoantigens to provide personalized immunotherapies through their tumor specificity and immunogenicity, challenges related to the scarcity of immunogenic neoepitopes have prompted continuous research towards finding new tumor-associated antigens (TAAs) and broader therapeutic frameworks, which may now learn from the genuine successes obtained with neoantigens. As an example, human endogenous retroviruses (HERVs) have emerged as potential alternatives to tumor neoantigens due to their high tumoral expression and ability to elicit both T cell reactivity and B cell responses associated with the efficacy of existing immunotherapies. This review aims to assess the status and limitations of TSA-directed mRNA cancer vaccines and the lessons that can be derived from these and checkpoint inhibitor studies to guide TAA vaccine development. We expect that shared B cell, CD4 and CD8 T cell antigen presentation will be key to stimulate continuous T cell expansion and efficacy for tumors that do not contain pre-existing tertiary lymphoid structures. When these structures are present in highly mutated tumors, the current checkpoint-based immunotherapies show efficacy even in immune privileged sites, and vaccines may hold the key to broaden efficacy to more tumor types and stages. [ABSTRACT FROM AUTHOR]

CD40–CD40 ligand interactions are critical for controlling Pneumocystis infection. However, which CD40-expressing cell populations are important for this interaction have not been well defined. We used a cohousing mouse model of Pneumocystis infection, combined with flow cytometry and quantitative polymerase chain reaction, to examine the ability of different populations of cells from C57BL/6 mice to reconstitute immunity in CD40 knockout mice. Unfractionated splenocytes, as well as purified B cells, were able to control Pneumocystis infection, while B cell–depleted splenocytes and unstimulated bone marrow–derived dendritic cells were unable to control infection in CD40 knockout mice. Pneumocystis antigen–pulsed bone marrow–derived dendritic cells showed early but limited control of infection. Additional findings were consistent with recent studies that suggested a role for antigen presentation by B cells; specifically, by using cells from immunized animals, B cells were able to present Pneumocystis antigens to induce proliferation of T cells. Thus, CD40 expression by B cells appears necessary for robust immunity to Pneumocystis. [ABSTRACT FROM AUTHOR]

Background: Tumor cells develop multiple mechanisms to facilitate their immune evasion. Identifying tumor-intrinsic factors that support immune evasion may provide new strategies for cancer immunotherapy. We aimed to explore the function and the mechanism of the tumor-intrinsic factor NPM1, a multifunctional nucleolar phosphoprotein, in cancer immune evasion and progression. Methods: The roles of NPM1 in tumor progression and tumor microenvironment (TME) reprogramming were examined by subcutaneous inoculation of Npm1-deficient tumor cells into syngeneic mice, and then explored by CyTOF, flow cytometry, immunohistochemistry staining, and RNA-seq. The in-vitro T-cell killing of OVA-presenting tumor cells by OT-1 transgenic T cells was observed. The interaction of NPM1 and IRF1 was verified by Co-IP. The regulation of NPM1 in IRF1 DNA binding to Nlrc5, Ciita promoter was determined by dual-luciferase reporter assay and ChIP-qPCR. Results: High levels of NPM1 expression predict low survival rates in various human tumors. Loss of NPM1 inhibited tumor progression and enhanced the survival of tumor-bearing mice. Npm1-deficient tumors showed increased CD8+ T cell infiltration and activation alongside the reduced presence of immunosuppressive cells. Npm1 deficiency increased MHC-I and MHC-II molecules and specific T-cell killing. Mechanistically, NPM1 associates with the transcription factor IRF1 and then sequesters IRF1 from binding to the Nlrc5 and Ciita promoters to suppress IRF1-mediated expression of MHC-I and MHC-II molecules in tumor cells. Conclusions: Tumor-intrinsic NPM1 promotes tumor immune evasion via suppressing IRF1-mediated antigen presentation to impair tumor immunogenicity and reprogram the immunosuppressive TME. Our study identifies NPM1 as a potential target for improving cancer immunotherapy. [ABSTRACT FROM AUTHOR]

The regulation of intracellular ionic homeostasis to trigger antigen-specific immune responses has attracted extensive interest in tumor therapy. In this study, we developed a dual-pathway nanoreactor, Au-Cu 2-x Se@ZIF-8@P18 NPs (ACS-Z-P NPs), which targets danger-associated molecular patterns (DAMPs) and releases Zn2+ and reactive oxygen species (ROS) within the tumor microenvironment (TME). Zn2+ released from the metal–organic frameworks (MOFs) was deposited in the cytoplasm, leading to aberrant transcription levels of intracellular zinc-regulated proteins and DNA damage, thereby inducing pyroptosis and immunogenic cell death (ICD) dependent on caspase1/gasdermin D (GSDMD) pathway. Furthermore, upon laser irradiation, ACS-Z-P NPs could break through the limitations of inherent defects of immunosuppression in TME, enhance ROS generation through a Fenton-like reaction cascade, which subsequently triggered the activation of inflammatory vesicles and the release of damage-associated molecular patterns (DAMPs). This cascade effect led to the amplification of pyroptosis and immunogenic cell death (ICD), thereby remodeling the immunosuppressed TME. Consequently, this process improved dendritic cell (DC) antigen presentation and augmented anti-tumor T-cell responses, effectively initiating antigen-specific immune responses and further enhancing pyroptosis and ICD. This study explores the therapeutic properties of these mechanisms in detail. The synthesized Au-Cu 2-x Se@ZIF-8@P18 nanoparticles (ACS-Z-Ps) can effectively enhance the bodyʼs immune response by regulating zinc ion levels within cells. This regulation leads to abnormal levels of zinc-regulated protein transcription and DNA damage, which induces cellular pyroptosis. As a result, antigen presentation to dendritic cells (DCs) is improved, and anti-tumor T-cell responses are enhanced. The ACS-Z-P NPs overcome the limitations of ROS deficiency and immunosuppression in the tumor microenvironment by using H 2 O 2 in the tumor microenvironment through a Fenton-like reaction. This leads to an increased production of ROS and O 2 , remodeling of the immunosuppressed tumor microenvironment, and enhanced induction of cell pyroptosis and immunogenic cell death. ACS-Z-P NPs targeted B16 cells using the photosensitizer P18 in combination with PDT treatment. This approach significantly inhibited the proliferation of B16 cells and effectively inhibited tumor growth. [Display omitted] [ABSTRACT FROM AUTHOR]

Pseudorabies virus (PRV) can establish lifelong latent infection in peripheral nervous ganglion, and persistent infections in peripheral blood lymphocytes. Establishing an infection in the lymphocytes does not only enable the PRV to escape host immune surveillance but pass through the placental barrier, leading to fetal death and abortion. Due to the pathogenicity of the PRV, it poses a huge challenge in its prevention and control. The PRV escapes host immunity through downregulation of swine leukocyte antigen class I (SLA I) molecules on infected cells. However, data on the molecular mechanisms of the SLA I suppression remains scant. Here, in order to verify the effect of candidate proteins PRV pUL44 and pUS6 on PRV immune escape related molecules SLA I and peptide loading complex (PLC), we detected the expression of SLA I and PLC components after expressing PRV pUL44 and pUS6. The effects of pUS6 and pUL44 on SLA I and PLC were analyzed by qRT-PCR and Western blot at mRNA and protein level, respectively. Cells expressing pUS6 or pUL44 genes showed a significantly suppressed expression of surface and total SLA I molecules. In addition, unlike UL44, the US6 gene was shown to downregulate the transporter associated with antigen processing 1 (TAP1), TAP2 and Tapasin molecules. The results show that PRV pUS6 may participate in virus immune escape by directly regulating the SLA I, TAP dimer and Tapasin molecules, thus blocking the transportation of TAP-bound peptides to the ER to bind SLA I molecules. We provide a theoretical basis on the mechanism of TAP mediated immune escape by the PRV. [ABSTRACT FROM AUTHOR]

Immunotherapy offers a promising avenue for reducing tumor metastasis and recurrence but faces challenges from the tumor immunosuppressive microenvironment (TIME) and restricted antigen presentation. To address these challenges, this study have developed an innovative approach utilizing molybdenum (Mo)‐doped Prussian blue nanoparticles coated with a cancer cell membrane (CCM), referred to as PMo@CCM. This novel nanoplatform excels in performing photothermal therapy (PTT), while the Mo and Fe components effectively deplete glutathione (GSH) and generate reactive oxygen species (ROS), thereby significantly enhancing chemodynamic therapy (CDT) and remodeling the TIME. The synergistic PTT/CDT approach not only induces tumor immunogenic cell death (ICD) but also facilitates antigen presentation. The CCM coating further supplies antigens and prompts dendritic cell (DC) maturation. This comprehensive strategy markedly enhances the effectiveness of immunotherapy, as evidenced by a significant increase in T cell activation. Moreover, the use of programmed cell death protein 1 antibodies (anti PD‐1) effectively blocks the PD‐1 immune checkpoint pathway. RNA sequencing analysis has identified genes associated with the observed substantial reduction in tumor growth. In conclusion, the PMo@CCM nanoplatform enables homologously targeted tumor synergistic therapy, guided by photothermal and magnetic resonance imaging (PTI&MRI), significantly impeding the progression of both primary and metastatic tumors. [ABSTRACT FROM AUTHOR]

Objective: To establish a method for detecting the binding affinity of peptides to HLA-B*1301 by HLA molecular reconstitution after weak acid treatment, and its practicality was evaluated. Methods: C1R cells overexpressing HLA-B*1301 were treated with citrate buffer of different pH for different time. After neutralization of pH, cells were resuspended in culture medium containing β2m and brefeldin A. Cells were incubated at 37 °C with peptide (peptide group) or without peptide (blank control), after addition of anti-HLA antibody, the cells were detected by flow cytometry. Ratio of fluorescence intensity between peptide group and blank control group was used as an index to measure the level of HLA molecular remodeling, and then represented the interactions between peptide and HLA-B*1301 molecule. Results: HLA-polypeptide complex was denatalized and dissociated after being treated with pH3.0 buffer for 1 min, and only HLA heavy chain molecules were retained on the cell surface. The addition of peptides with binding force could significantly improve the level of HLA molecular remodeling, and the binding force of peptides with HLA-B*1301 could be evaluated by this method. Conclusion: HLA molecular reconstitution assay is a simple and reliable method to detect the binding of peptides to HLA-B*1301, which can also provide reference for the study of other low frequency HLA molecular antigen presentation patterns. [ABSTRACT FROM AUTHOR]

Objective: To establish a method for detecting the binding affinity of peptides to HLA-B*1301 by HLA molecular reconstitution after weak acid treatment, and its practicality was evaluated. Methods: C1R cells overexpressing HLA-B*1301 were treated with citrate buffer of different pH for different time. After neutralization of pH, cells were resuspended in culture medium containing β2m and brefeldin A. Cells were incubated at 37 °C with peptide (peptide group) or without peptide (blank control), after addition of anti-HLA antibody, the cells were detected by flow cytometry. Ratio of fluorescence intensity between peptide group and blank control group was used as an index to measure the level of HLA molecular remodeling, and then represented the interactions between peptide and HLA-B*1301 molecule. Results: HLA-polypeptide complex was denatalized and dissociated after being treated with pH3.0 buffer for 1 min, and only HLA heavy chain molecules were retained on the cell surface. The addition of peptides with binding force could significantly improve the level of HLA molecular remodeling, and the binding force of peptides with HLA-B*1301 could be evaluated by this method. Conclusion: HLA molecular reconstitution assay is a simple and reliable method to detect the binding of peptides to HLA-B*1301, which can also provide reference for the study of other low frequency HLA molecular antigen presentation patterns. [ABSTRACT FROM AUTHOR]

Interferon Gamma Inducible Protein 30 (IFI30), also known as Gamma-Interferon-Inducible Lysosomal Thiol Reductase (GILT), is predominantly found in lysosomes and the cytoplasm. As the sole enzyme identified to catalyze disulfide bond reduction in the endocytic pathway, IFI30 contributes to both major histocompatibility complex (MHC) class I-restricted antigen cross-presentation and MHC class II-restricted antigen processing by decreasing the disulfide bonds of endocytosed proteins. Remarkably, emerging research has revealed that IFI30 is involved in tumorigenesis, tumor development, and the tumor immune response. Targeting IFI30 may provide new strategies for cancer therapy and improve the prognosis of patients. This review provided a comprehensive overview of the research progress on IFI30 in tumor progression, cellular redox status, autophagy, tumor immune response, and drug sensitivity, with a view to providing the theoretical basis for pharmacological intervention of IFI30 in tumor therapy, particularly in immunotherapy. [ABSTRACT FROM AUTHOR]

Despite recent advances in immunotherapy, its efficacy remains constrained by the absence of immune coordination. Especially, the interplay between tumor‐draining lymph nodes (TDLNs) and tumors is frequently disregarded. Here, a self‐adjuvanting hydrogel capable of eliciting a powerful and sustained immune response is developed. Briefly, the engineered arabinose response bacteria (ARB) expressing IL‐15 and mannose‐modified hollow mesoporous Prussian blue nanoparticles (NPs) loaded with vitamin E (Man/HMPB(VE), MHV) are mixed with arabinose hydrogel (AraGel), forming the system designated as AraGel@ARB/MHV (AAM). Employing mild photothermal therapy mediated by MHV, immunogenic cell death (ICD) triggers the release of tumor‐associated antigens. Subsequently, Man‐modified NPs target TDLNs and release VE, which suppresses the checkpoint Src homology region 2 domain‐containing phosphatase‐1 (SHP1) in dendritic cells, thereby enhancing antigen presentation and T cell activation. Meanwhile, IL‐15 expression of ARB(IL‐15) induced by AraGel degradation enables ARB to serve as an enhanced adjuvant in a self‐adjuvanting manner, working synergistically with ICD and TDLN reprogramming to promote cytotoxic T lymphocytes activation. The hydrogel system efficiently suppresses tumor growth by eliciting prolonged and powerful immunotherapy in an orchestrated manner. Overall, the self‐adjuvanting hydrogel holds great potential for cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Astrocytes respond to infection, injury, and disease with a robust and heterogeneous set of responses often associated with inflammation. Astrocyte heterogeneity is largely modeled at the descriptive level, with the identification of novel signatures of gene expression, proteins, and lipids that are tightly spatiotemporally controlled. While traditionally thought of as passive responders, astrocytes are active contributors to inflammation and release several effector cytokines and chemokines that help to modulate immune responses. In vertebrates, some astrocytes may even be involved in the presentation of antigens to infiltrating T cells. This places them as key initiators of the earliest response to inflammation, without the need for a myeloid cell intermediary. Astrocytes are key modulators of the inflammatory immune response in the mammalian central nervous system (CNS). While traditionally thought of as having only passive roles in the response to inflammatory insults, recent evidence indicates that astrocytes are active players in the earliest stages of inflammation, and may even have a role as atypical antigen-presenting cells. The astrocyte, a major glial cell type in the central nervous system (CNS), is widely regarded as a functionally diverse mediator of homeostasis. During development and throughout adulthood, astrocytes have essential roles, such as providing neuron metabolic support, modulating synaptic function, and maintaining the blood–brain barrier (BBB). Recent evidence continues to underscore their functional heterogeneity and importance for CNS maintenance, as well as how these cells ensure optimal CNS and immune responses to disease, acute trauma, and infection. Advances in our understanding of neuroimmune interactions complement our knowledge of astrocyte functional heterogeneity, where astrocytes are now regarded as key effectors and propagators of immune signaling. This shift in perspective highlights the role of astrocytes not merely as support cells, but as active participants in CNS immune responses. [ABSTRACT FROM AUTHOR]

Background: In order for cancers to progress, they must evade elimination by CD8 T cells or other immune mechanisms. CD8 T cells recognize and kill tumor cells that display immunogenic tumor peptides bound to MHC I molecules. One of the ways that cancers can escape such killing is by reducing expression of MHC I molecules, and loss of MHC I is frequently observed in tumors. There are multiple different mechanisms that can underly the loss of MHC I complexes on tumor and it is currently unclear whether there are particular mechanisms that occur frequently and, if so, in what types of cancers. Also of importance to know is whether the loss of MHC I is reversible and how such loss and/or its restoration would impact responses to immunotherapy. Here, we investigate these issues for loss of IRF1 and IRF2, which are transcription factors that drive expression of MHC I pathway genes and some killing mechanisms. Methods: Bioinformatics analyses of IRF2 and IRF2-dependent gene transcripts were performed for all human cancers in the TCGA RNAseq database. IRF2 protein-DNA-binding was analyzed in ChIPseq databases. CRISRPcas9 was used to knock out IRF1 and IRF2 genes in human and mouse melanoma cells and the resulting phenotypes were analyzed in vitro and in vivo. Results: Transcriptomic analysis revealed that IRF2 expression was reduced in a substantial subset of cases in almost all types of human cancers. When this occurred there was a corresponding reduction in the expression of IRF2-regulated genes that were needed for CD8 T cell recognition. To test cause and effect for these IRF2 correlations and the consequences of IRF2 loss, we gene-edited IRF2 in a patient-derived melanoma and a mouse melanoma. The IRF2 gene-edited melanomas had reduced expression of transcripts for genes in the MHC I pathway and decreased levels of MHC I complexes on the cell surface. Levels of Caspase 7, an IRF2 target gene involved in CD8 T cell killing of tumors, were also reduced. This loss of IRF2 caused both human and mouse melanomas to become resistant to immunotherapy with a checkpoint inhibitor. Importantly, these effects were reversible. Stimulation of the IRF2-deficient melanomas with interferon induced the expression of a functionally homologous transcription factor, IRF1, which then restored the MHC I pathway and responsiveness to CPI. Conclusions: Our study shows that a subset of cases within most types of cancers downregulates IRF2 and that this can allow cancers to escape immune control. This can cause resistance to checkpoint blockade immunotherapy and is reversible with currently available biologics. [ABSTRACT FROM AUTHOR]

To eliminate infected and cancerous cells, antigen processing and presentation play a pivotal role through the recognition of antigenic peptides displayed on Major Histocompatibility Complex class I (MHC I) molecules. Here, we developed a photostimulated antigen release system that enables the temporal inception of antigen flux. Simple and effective photocaging of the human immunodeficiency virus (HIV)‐Nef73‐derived epitope, a representative high‐affinity MHC I ligand, was provided by steric hindrance to block the recognition by the transporter associated with antigen processing (TAP) in the peptide loading complex (PLC). In response to light, a heteronomous release of antigens and subsequent translocation in various scenarios is demonstrated, including a TAP‐related ATP‐binding cassette (ABC) transporter reconstituted in liposomes and the native PLC in the endoplasmic reticulum (ER) membrane of human cells. The photochemically induced 'burst' of antigens opens new opportunities for a mechanistic analysis of the antigen translocation machinery and will help to provide insights into antigen processing pathways via an on‐demand, subcellular pulse‐chase release of antigens. [ABSTRACT FROM AUTHOR]

Background Amelanotic acral melanoma (AAM) is a rare type of acral melanoma that has a poor prognosis. Objectives To investigate the transcriptomic differences between AAM and pigmented acral melanoma (PAM). Methods Differences in the spatially resolved transcriptomic profiles of 9 patients with AAM with 29 regions of interest (ROIs) and 11 patients with PAM with 46 ROIs were investigated using S100b and CD3 morphology markers. Results In S100b+ tumour cell areas, we detected 11 upregulated differentially expressed genes (DEGs; including chaperone/ubiquitin--associated DEGs) and 82 downregulated DEGs (including human leucocyte antigen) in AAMs vs. PAMs. Protein–protein interaction network and pathway analyses revealed significant enrichment of dysregulated translational and nonsense-mediated decay pathways but significant decreases in antigen processing and presentation, interferon signalling and melanin biosynthesis pathways in S100b+ ROIs of AAMs compared with PAMs. In tumour-associated immune cell areas, the numbers of CD8 T cells (P = 0.04) and M1 macrophages (P = 0.01) were significantly decreased, whereas those of monocytes (P = 0.04) and endothelial cells (P = 0.04) were increased in AAMs compared with PAMs. Conclusions These findings could widen our understanding of the biological differences between AAMs and PAMs, which might result in a different clinical course. [ABSTRACT FROM AUTHOR]

Controlled-release systems enhance anti-tumor effects by leveraging local antigen persistence for antigen-presenting cells (APCs) recruitment and T cell engagement. However, constant antigen presentation alone tends to induce dysfunction in tumor-specific CD8+ T cells, neglecting the synergistic effects of co-stimulatory signal. To address this, we developed a soft particle-stabilized emulsion (SPE) to deliver lipopeptides with controlled release profiles by adjusting their hydrophobic chain lengths: C 6 -SPE (fast release), C 10 -SPE (medium release), and C 16 -SPE (slow release). Following administration, C 6 -SPE release antigen rapidly, inducing early antigen presentation, whereas C 16 -SPE's slow-release delays antigen presentation. Both scenarios missed the critical window for coordinating with the expression of CD86, leading to either T cell apoptosis or suboptimal activation. In contrast, C 10 -SPE achieved a spatiotemporally synergetic effect of the MHC-I-peptide complex and co-stimulatory signal (CD86), leading to effective dendritic cell (DC) activation, enhanced T cell activation, and tumor regression in EG7-OVA bearing mice. Additionally, co-delivery of cytosine-phosphate-guanine (CpG) with SPE provided a sustained expression of the CD86 window for DC activation, improving the immune response and producing robust anti-tumor effects with C 6 -SPE comparable to C 10 -SPE. These findings highlight that synchronizing the spatiotemporal dynamics of antigen presentation and APC activation may confer an optimal strategy for enhanced vaccinations. [Display omitted] [ABSTRACT FROM AUTHOR]

Immunological adjuvants are vaccine components that enhance long-lasting adaptive immune responses to weakly immunogenic antigens. Monophosphoryl lipid A (MPLA) is a potent and safe vaccine adjuvant that initiates an early innate immune response by binding to the Toll-like receptor 4 (TLR4). Importantly, the binding and recognition process is highly dependent on the monomeric state of MPLA. However, current vaccine delivery systems often prioritize improving the loading efficiency of MPLA, while neglecting the need to maintain its monomeric form for optimal immune activation. Here, we introduce a Pickering emulsion-guided MPLA monomeric delivery system (PMMS), which embed MPLA into the oil-water interface to achieve the monomeric loading of MPLA. During interactions with antigen-presenting cells, PMMS functions as a chaperone for MPLA, facilitating efficient recognition by TLR4 regardless of the presence of lipopolysaccharide-binding proteins. At the injection site, PMMS efficiently elicited local immune responses, subsequently promoting the migration of antigen-internalized dendritic cells to the lymph nodes. Within the draining lymph nodes, PMMS enhanced antigen presentation and maturation of dendritic cells. In C57BL/6 mice models, PMMS vaccination provoked potent antigen-specific CD8+ T cell-based immune responses. Additionally, PMMS demonstrated strong anti-tumor effects against E.G7-OVA lymphoma. These data indicate that PMMS provides a straightforward and efficient strategy for delivering monomeric MPLA to achieve robust cellular immune responses and effective cancer immunotherapy. Pickering emulsion-guided MPLA monomeric delivery system as a chaperone for MPLA, facilitating the efficient recognition of MPLA-TLR4. [Display omitted] • We construct a Pickering emulsion-guided MPLA monomeric delivery system (PMMS). • PMMS as a chaperone for MPLA, facilitating the efficient recognition of MPLA-TLR4. • PMMS can elicit robust cellular immune responses. • PMMS can achieve enhanced cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Oral lichen planus (OLP) is a chronic inflammatory disease with obscure etiopathogenesis. Macrophages play an important role in interaction between innate and adaptive immunity. This study aimed to investigate the macrophage phenotypes and obtain more comprehensive gene characteristics of macrophages in OLP. Double cluster of differentiation (CD) 68/CD86 and CD68/CD206 immunofluorescence staining was conducted in 11 biopsy-proven OLP tissue samples and 5 health control (HC) to represent M1 and M2 macrophages, respectively. The number of positively stained cells was manually counted, and the density was calculated. Furtherly, OLP single-cell dataset GSE211630 was downloaded from Gene Expression Omnibus. Gene characteristics and functional analysis of the macrophages were elucidated. In the OLP group, the densities of M1 (P < 0.001), M2 macrophages (P < 0.001) and M1/M2 ratio (P = 0.001) were significantly higher than those in HC group. Single-cell RNA sequencing revealed that proportions of CXCL10 macrophages (P = 0.003), IL1B/MMP19 macrophages (P < 0.001) were increased in OLP tissues compared with those in HC. Macrophages in OLP tissues had a stronger ability to cell chemotaxis, positive regulation of cell adhesion and antigen processing and presentation. Functional analysis revealed macrophages in OLP tissues could interact with multiple immune cells, and multiple signaling pathways were associated with macrophages in OLP. A pro-inflammatory status of macrophages with different gene characteristics was found in the microenvironment of OLP by integrating immunofluorescence double staining and single-cell RNA sequencing, which provided a potential target for clinical treatment of OLP. [ABSTRACT FROM AUTHOR]

Immunotherapy successfully complements traditional cancer treatment. However, primary and acquired resistance might limit efficacy. Reduced antigen presentation by MHC-I has been identified as potential resistance factor. Here we show that the epigenetic regulator ubiquitin-like with PHD and ring finger domains 1 (UHRF1), exhibits altered expression and aberrant cytosolic localization in cancerous tissues, where it promotes MHC-I ubiquitination and degradation. Cytoplasmic translocation of UHRF1 is induced by its phosphorylation on a specific serine in response to signals provided by factors present in the tumor microenvironment (TME), such as TGF-β, enabling UHRF1 to bind MHC-I. Downregulation of MHC-I results in suppression of the antigen presentation pathway to establish an immune hostile TME. UHRF1 inactivation by genetic deletion synergizes with immune checkpoint blockade (ICB) treatment and induces an anti-tumour memory response by evoking low-affinity T cells. Our study adds to the understanding of UHRF1 in cancer immune evasion and provides a potential target to synergize with immunotherapy and overcome immunotherapeutic resistance. MHC-I mediated antigen presentation is an important element of the anti-tumour immune response. Here authors identify a tumour immune escape mechanism by which the cancer cells express the ubiquitin E3 ligase UHRF1 in the cytoplasm instead of the nuclear expression pattern observed in normal tissues, and this results in degradation of MHC-I and thus diminished antigen presentation and anti-tumour T cell response. [ABSTRACT FROM AUTHOR]

Highlights: We classified the carriers that built cancer nanovaccines, discussed their diversified applications and coincidently compared their advantages and disadvantages. Various cellular targets that guide the design and engineering of cancer nanovaccines are categorized and their characteristics and benefits are highlighted. The clinical cases and encountered challenges in cancer nanovaccines are discussed, during which reasonable solutions and future research direction are provided. 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. [ABSTRACT FROM AUTHOR]

Background: Antigen presentation is a central step in initiating and shaping the adaptive immune response. To activate CD8+ T cells, pathogen-derived peptides are presented on the cell surface of antigen-presenting cells bound to major histocompatibility complex (MHC) class I molecules. CD8+ T cells that recognize these complexes with their T cell receptor are activated and ideally eliminate infected cells. Prediction of putative peptides binding to MHC class I (MHC-I) is crucial for understanding pathogen recognition in specific immune responses and for supporting drug and vaccine design. There are reliable databases for epitope prediction algorithms available however they primarily focus on the prediction of epitopes in single immunogenic proteins. Results: We have developed the tool DiscovEpi to establish an interface between whole proteomes and epitope prediction. The tool allows the automated identification of all potential MHC-I-binding peptides within a proteome and calculates the epitope density and average binding score for every protein, a protein-centric approach. DiscovEpi provides a convenient interface between automated multiple sequence extraction by organism and cell compartment from the database UniProt for subsequent epitope prediction via NetMHCpan. Furthermore, it allows ranking of proteins by their predicted immunogenicity on the one hand and comparison of different proteomes on the other. By applying the tool, we predict a higher immunogenic potential of membrane-associated proteins of SARS-CoV-2 compared to those of influenza A based on the presented metrics epitope density and binding score. This could be confirmed visually by comparing the epitope maps of the influenza A strain and SARS-CoV-2. Conclusion: Automated prediction of whole proteomes and the subsequent visualization of the location of putative epitopes on sequence-level facilitate the search for putative immunogenic proteins or protein regions and support the study of adaptive immune responses and vaccine design. [ABSTRACT FROM AUTHOR]

Endothelial cells are critical in tumor development, and the specific targeting of endothelial cells offers a potent means to effectively impede angiogenesis and suppress the growth of tumors. Tumor endothelial cells are responsible for the loss of anticancer immunity, the so-called endothelial anergy, i.e., the unresponsiveness of tumor endothelial cells to pro-inflammatory stimulation, not allowing adhesion of immune cells to the endothelium. Endothelial cells downregulate antigen presentation and recruitment of immune cells, contributing to immunosuppression. Targeting endothelial cells may assist in improving the immune effect of immune cells in tumor microenvironment. [ABSTRACT FROM AUTHOR]