CCR7 and its ligands: balancing immunity and tolerance

Tough and waterproof microneedles overcome mucosal immunotolerance by modulating antigen release patterns

Mucosal vaccines are considered an ideal choice for combating mucosal pathogens due to their ability to neutralize pathogens at the first line of defense. However, the development of mucosal subunit vaccines is constricted by rigorous challenges, such as low immunogenicity, poor antigen delivery efficiency, and mucosal tolerance. Here, a buccal microneedle patch incorporated with engineered nanoparticles loaded with urease B subunit (rUreB) was developed to overcome the above challenges. Specifically, an engineered nanocarrier was developed to protect the antigen and modulate its release profile. Then, the nanoparticles were enriched to form microneedle tips with superior mechanical and waterproof properties, allowing effective penetration of the buccal mucosa and resistance to salivary washout. Besides, the microneedles demonstrated an S-curve antigen release pattern which was crucial for the recruitment of antigen presenting cells (APCs) and the downregulation of mucosal tolerogenic DCs and Treg cells. The buccal microneedle vaccine without any immune stimulators induced potent systemic and mucosal immune responses, resulting in superior protection of mice from the oral challenge of Helicobacter pylori. These results suggested that the rationally designed buccal microneedle vaccine can effectively overcome mucosal delivery barriers and mucosal tolerance, providing a promising alternative strategy for mucosal vaccination of subunit antigens.

Structure-activity relationship study of navarixin analogues as dual CXCR2 and CCR7 antagonists

Despite the promise of the human chemokine receptor 7 (CCR7) as drug target for the treatment of cancer metastasis and autoimmune diseases, there are no potent and selective CCR7 antagonists known in literature. In this work, a 1,2,5-thiadiazole 1,1-dioxide with low μM activity as a CXCR2 and CCR7 antagonist was selected as starting point for a structure-activity relationship study. The replacement of the central thiadiazole dioxide motif with squaramide led to low nanomolar CCR7 antagonism. Additional systematic structural variations afforded various squaramide analogues that displayed potent CCR7 antagonism in a calcium mobilization assay with IC50 values in the low nM range. Unfortunately, the same compounds also displayed potent CXCR2 antagonistic activity and should therefore be considered as dual CCR7/CXCR2 antagonists.

Combining spatial transcriptomics and ECM imaging in 3D for mapping cellular interactions in the tumor microenvironment

Tumors are complex ecosystems composed of malignant and non-malignant cells embedded in a dynamic extracellular matrix (ECM). In the tumor microenvironment, molecular phenotypes are controlled by cell-cell and ECM interactions in 3D cellular neighborhoods (CNs). While their inhibition can impede tumor progression, routine molecular tumor profiling fails to capture cellular interactions. Single-cell spatial transcriptomics (ST) maps receptor-ligand interactions but usually remains limited to 2D tissue sections and lacks ECM readouts. Here, we integrate 3D ST with ECM imaging in serial sections from one clinical lung carcinoma to systematically quantify molecular states, cell-cell interactions, and ECM remodeling in CN. Our integrative analysis pinpointed known immune escape and tumor invasion mechanisms, revealing several druggable drivers of tumor progression in the patient under study. This proof-of-principle study highlights the potential of in-depth CN profiling in routine clinical samples to inform microenvironment-directed therapies. A record of this paper's transparent peer review process is included in the supplemental information.

Tissue-resident memory T cells and their function in skin diseases

ABSTRACT

Tissue-resident memory T (TRM) cells are a recently defined subtype of non-recirculating memory T cells with longevity and protective functions in peripheral tissues. As an essential frontline defense against infections, TRM cells have been reported to robustly patrol the tissue microenvironment in malignancies. Accumulating evidence also implicates that TRM cells in the relapse of chronic inflammatory skin diseases such as psoriasis and vitiligo. In light of these developments, this review aims to synthesize these recent findings to enhance our understanding of TRM cell characteristics and actions. Therefore, after providing a brief overview of the general features of the TRM cells, including precursors, homing, retention, and maintenance, we discuss recent insights gained into their heterogeneous functions in skin diseases. Specifically, we explore their involvement in conditions such as psoriasis, vitiligo, fixed drug eruption - dermatological manifestations of drug reactions at the same spot, cutaneous T cell lymphoma, and melanoma. By integrating these diverse perspectives, this review develops a comprehensive model of TRM cell behavior in various skin-related pathologies. In conclusion, our review emphasizes that deciphering the characteristics and mechanisms of TRM cell actions holds potential not only for discovering methods to slow cancer growth but also for reducing the frequency of recurrent chronic inflammation in skin tissue.

Comprehensive analysis of B cell repopulation in ocrelizumab-treated patients with multiple sclerosis by mass cytometry and proteomics

Ocrelizumab, an anti-CD20 antibody, depletes CD20+ B cells, which subsequently repopulate over months. Little is known about changes in other immune cell populations and molecular markers associated with B cell repopulation. Here, we performed a comprehensive characterization of immune cells from ocrelizumab-treated patients with multiple sclerosis (MS) using mass cytometry. About 50% of patients showed naive B cell repopulation after 6 months mainly with a transitional phenotype, whereas CD27+ memory B cells only rarely repopulated. This repopulation was associated with a reduction of memory T cells and activated myeloid cells, as well as reduced expression of activation/migration markers in both cell types. A plasma proteomics analysis identified proteins including TNFRSF13C, associated with B cell depletion and repopulation. Plasma levels of neurofilament light-chain protein declined after ocrelizumab treatment was not linked with B cell repopulation. These findings identify potential soluble markers for monitoring of ocrelizumab treatment in MS.

A cloaked human stem-cell-derived neural graft capable of functional integration and immune evasion in rodent models

Human pluripotent stem cell (hPSC)-derived therapies are a realistic possibility for numerous disorders, including Parkinson's disease. While generating replacement neurons is achievable, immunosuppressive drug challenges, to prevent rejection, remain. Here we adopted a hPSC line (termed H1-FS-8IM), engineered to overexpress 8 immunomodulatory transgenes, to enable transplant immune evasion. In co-cultures, H1-FS-8IM PSC-derived midbrain neurons evaded rejection by T lymphocytes, natural killer cells, macrophages, and dendritic cells. In humanized mice, allogeneic H1-FS-8IM neural grafts evaded rejection, while control hPSC-derived neural grafts evoked activation of human immune cells, elevated inflammatory cytokines in blood and cerebrospinal fluid, and caused spleen and lymph node enlargement. H1-FS-8IM neural grafts retained functionality, reversing motor deficits in Parkinsonian rats. Additional incorporation of a suicide gene into the H1-FS-8IM hPSC line enabled proliferative cell elimination within grafts. Findings demonstrate feasibility of generating a population-wide applicable, safe, off-the-shelf cell product, suitable for treating diseases for which cell-based therapies are a viable option.

Trichinella spiralis extracellular vesicles induce anti-inflammatory and regulatory immune responses in vitro

The helminth Trichinella spiralis, through its excretory-secretory (ES L1) products, induces immune regulatory mechanisms that modulate the host's immune response not only to itself, but also to bystander antigens, foreign or self in origin, which can result in the alleviation of inflammatory diseases. Under the influence of ES L1, dendritic cells (DCs) acquire a tolerogenic phenotype and the capacity to induce Th2 and regulatory responses. Since ES L1 products represent a complex mixture of proteins and extracellular vesicles (TsEVs) the aim of this study was to investigate the impact of TsEVs, isolated from ES L1 products, on phenotypic and functional characteristics of DCs and to elucidate whether TsEVs could reproduce the immunomodulatory effects of the complete ES L1 product. Monocyte-derived DCs treated with TsEVs acquired semi-matured phenotypes, characterized by low expression of human leukocyte antigen - DR isotype (HLA-DR), cluster of differentiation (CD) 86 (CD86), and CD40, moderate expression of CD83 and C-C chemokine receptor type 7 (CCR7), and increased expression of tolerogenic markers indoleamine 2,3-dioxygenase 1 (IDO-1) and immunoglobulin-like transcript 3 (ILT3), together with the unchanged production of IL-12 and IL-23, and elevated production of IL-10 and transforming growth factor (TGF)-β, compared with controls. Gene expression analysis of TsEV-treated DCs revealed elevated levels of mTOR, Ahr, NF-κB2, RelB, SOCS1 and SOCS3, which participate in signaling pathways involved in DC maturation and the subsequent regulation of release of both anti-inflammatory and pro-inflammatory cytokines. TsEVs promoted the capacity of DCs to drive polarization of Th2 and anti-inflammatory responses, and impaired their capacity to induce Th1/Th17 polarization. Moreover, TsEV-treated DCs possessed a high capacity to induce conventional FoxP3 + regulatory T cells, as well as unconventional T regulatory (Tr1) cells. Tolerogenic properties of TsEV-treated DCs were retained even after challenge with a pro-inflammatory stimulus. These findings highlight the potential of TsEVs to induce immune tolerance, suggesting their potential use as therapeutics for the treatment of inflammatory disorders.

Enhancing Immune Responses Through Modulation of Innate Cell Microenvironments in Lymph Nodes with Virus-Mimetic Vaccines

Nanovaccines hold significant promise for the prevention and treatment of infectious diseases. However, the efficacy of many nanovaccines is often limited by inadequate stimulation of both innate and adaptive immune responses. Herein, we explore a rational vaccine strategy aimed at modulating innate cell microenvironments within lymph nodes (LNs) to enhance the generation of effective immune responses. Inspired by the structure and natural infection process of viruses, we developed a versatile antigen and adjuvant co-delivery platform, termed virus-mimetic vaccines (VMVs). Specifically, polyarginine-tagged antigens were noncovalently assembled onto nucleic acid nanogels containing cytosine-phosphate-guanine oligodeoxynucleotide via a salt-bridge zipper mechanism, which can activate Toll-like receptor 9. Upon intramuscular immunization, VMVs effectively drained into the LNs, recruiting and activating multiple innate cells, including CD8+ dendritic cells (DCs), CD103+ DCs, macrophages, plasmacytoid DCs, and neutrophils. This activation modulates the innate cell microenvironments and relocates antigen-presenting cells within LNs, optimizing adaptive immune responses. VMVs induced a robust antigen-specific immune response, characterized by high levels of neutralizing antibodies, augmented memory T cell activity, and enhanced development of germinal center B cells. Together, our findings demonstrate that dynamic modulation of innate cell microenvironments by VMVs leads to optimized generation of both humoral and cellular immunity against infectious diseases.

The Clinicopathological and Prognostic Value of CCR7 Expression in Breast Cancer Throughout the Literature: A Systematic Review and Meta-Analysis

Background/Objective: This study aimed to determine the clinicopathological findings and prognostic value of chemokine receptor 7 (CCR7) expression in patients with breast cancer (BC). Methods: Up to the 25th of March 2025, a search was conducted using five databases: PubMed, Embase, Scopus, Medline, and Web of Science. The methodological standards for the epidemiological research scale were used to assess the quality of the included articles, and Stata software (Stata 19) was used to synthesize the meta-analysis. Results: We considered 12 of 853 studies that included 3119 patients with BC. High CCR7 expression was not associated with age (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.66-1.03); clinicopathological findings, including tumor size (OR 1.062, 95% CI 0.630-1.791); clinical stage (OR 1.753, 95% CI 0.231-13.304); nodal metastasis (OR 1.252, 95% CI 0.571-2.741); or histological differentiation (OR 1.167, 95% CI 0.939-1.450). CCR7 expression did not affect overall survival (hazard ratio 0.996, 95% CI 0.659-1.505). Conclusions: Our quantitative analysis did not reveal an association between CCR7 expression and poor clinicopathological or prognostic features in BC patients. Because of the high heterogeneity and potential publication bias, large high-quality studies are required to further confirm these findings.

Identification and Experimental Validation of NETosis-Mediated Abdominal Aortic Aneurysm Gene Signature Using Multi-omics, Machine Learning, and Mendelian Randomization

Abdominal aortic aneurysm (AAA) is a life-threatening disorder with limited therapeutic options. Neutrophil extracellular traps (NETs) are formed by a process known as "NETosis" that has been implicated in AAA pathogenesis, yet the roles and prognostic significance of NET-related genes in AAA remain poorly understood. This study aimed to identify key AAA- and NET-related genes (AAA-NETs-RGs), elucidate their potential mechanisms in contributing to AAA, and explore potential therapeutic compounds for AAA therapy. Through bioinformatics analysis of multiomics and machine learning, we identified six AAA-NETs-RGs: DUSP26, FCN1, MTHFD2, GPRC5C, SEMA4A, and CCR7, which exhibited strong diagnostic potential for predicting AAA progression, were significantly enriched in pathways related to cytokine-cytokine receptor interaction and chemokine signaling. Immune infiltration analysis revealed a causal association between AAA-NETs-RGs and immune cell infiltration. Cell-cell communication analysis indicated that AAA-NETs-RGs predominantly function in smooth muscle cells, B cells, T cells, and NK cells, primarily through cytokine and chemokine signaling. Gene profiling revealed that CCR7 and MTHFD2 exhibited the most significant upregulation in AAA patients compared to non-AAA controls, as well as in in vitro AAA models. Notably, genetic depletion of CCR7 and MTHFD2 strongly inhibited Ang II-induced phenotypic switching, functional impairment, and senescence in vascular smooth muscle cells (VSMCs). Based on AAA-NETs-RGs, molecular docking analysis combined with the Connectivity Map (CMap) database identified mirdametinib as a potential therapeutic agent for AAA. Mirdametinib effectively alleviated Ang II-induced phenotypic switching, biological dysfunction, and senescence. These findings provide valuable insights into understanding the pathophysiology of AAA and highlight promising therapeutic strategies targeting AAA-NETs-RGs.

Cancer metastasis: molecular mechanisms and therapeutic interventions

The metastatic cascade is a complicated process where cancer cells travel across multiple organs distant from their primary site of onset. Despite the wide acceptance of the 'seed and soil' theory, mechanisms driving metastasis organotropism remain mystery. Using breast cancer of different subtypes as the disease model, we characterized the 'metastatic profile of cancer cells' and the 'redox status of the organ microenvironment' as the primary determinants of cancer metastasis organotropism. Mechanically, we identified a positive correlation between cancer metabolic plasticity and stemness, and proposed oxidative stress as the selection power of cancer cells succeeding the metastasis cascade. Therapeutically, we proposed the use of pro-oxidative therapeutics in ablating cancer cells taking advantages of this fragile moment during metastasis. We comprehensively reviewed current pro-oxidative strategies for treating cancers that cover the first line chemo- and radio-therapies, approaches relying on naturally existing power including magnetic field, electric field, light and sound, nanoparticle-based anti-cancer composites obtained through artificial design, as well as cold atmospheric plasma as an innovative pro-oxidative multi-modal modality. We discussed possible combinations of pro-oxidative approaches with existing therapeutics in oncology prior to the forecast of future research directions. This paper identified the fundamental mechanics driving metastasis organotropism and proposed intervention strategies accordingly. Insights provided here may offer clues for the design of innovative solutions that may open a new paradigm for cancer treatment.

MIST: An interpretable and flexible deep learning framework for single-T cell transcriptome and receptor analysis

Joint analysis of transcriptomic and T cell receptor (TCR) features at single-cell resolution provides a powerful approach for in-depth T cell immune function research. Here, we introduce a deep learning framework for single-T cell transcriptome and receptor analysis, MIST (Multi-insight for T cell). MIST features three latent spaces: gene expression, TCR, and a joint latent space. Through analyses of antigen-specific T cells, and T cell datasets related to lung cancer immunotherapy and COVID19, we demonstrate MIST's interpretability and flexibility. MIST easily and accurately resolves cell function and antigen specificity by vectorizing and integrating transcriptome and TCR data of T cells. In addition, using MIST, we identified the heterogeneity of CXCL13+ subsets in lung cancer infiltrating CD8+ T cells and their association with immunotherapy, providing additional insights into the functional transition of CXCL13+ T cells related to anti-PD-1 therapy that were not reported in the original study.

Identification of novel IL17-related genes as prognostic and therapeutic biomarkers of psoriasis using comprehensive bioinformatics analysis and machine learning

Psoriasis is a common chronic skin disorder with a polygenic background. It is widely acknowledged that Th17/IL-17A axis plays a key role in the pathogenesis of psoriasis. However, numerous regulatory genes upstream of the pathway remain undiscovered, creating a knowledge gap in our understanding of the genetic aspects of the Th17/IL-17A axis. In this study, we employed machine learning algorithms to identify three target genes associated with psoriasis: CCR7, IL2RG, and PLEK. The validation of these genes was carried out in specimens from psoriatic patients. In vivo, investigations assessed the relationship between these three genes and IL-17A-related inflammation and their connection to psoriatic phenotypes. To further confirm the significance of the newly discovered gene, PLEK, we performed experiments involving the blockade of its expression. Our bioinformatics analysis revealed three novel genes closely linked to psoriasis: CCR7, IL2RG, and PLEK. These genes exhibited upregulated expression in psoriasis, consistently aligning with the Th17/IL-17A axis. Inhibition of PLEK expression reduced Th17/IL-17A-related inflammation and alleviated psoriatic phenotypes. CCR7, IL2RG, and PLEK show potential as three novel biomarkers for psoriasis, with PLEK being reported for the first time in this context. These genes contribute to pathogenesis by associating with the Th17/IL-17A signaling pathway.

Advances in Therapeutic Cancer Vaccines, Their Obstacles, and Prospects Toward Tumor Immunotherapy

Over the past few decades, cancer immunotherapy has experienced a significant revolution due to the advancements in immune checkpoint inhibitors (ICIs) and adoptive cell therapies (ACTs), along with their regulatory approvals. In recent times, there has been hope in the effectiveness of cancer vaccines for therapy as they have been able to stimulate de novo T-cell reactions against tumor antigens. These tumor antigens include both tumor-associated antigen (TAA) and tumor-specific antigen (TSA). Nevertheless, the constant quest to fully achieve these abilities persists. Therefore, this review offers a broad perspective on the existing status of cancer immunizations. Cancer vaccine design has been revolutionized due to the advancements made in antigen selection, the development of antigen delivery systems, and a deeper understanding of the strategic intricacies involved in effective antigen presentation. In addition, this review addresses the present condition of clinical tests and deliberates on their approaches, with a particular emphasis on the immunogenicity specific to tumors and the evaluation of effectiveness against tumors. Nevertheless, the ongoing clinical endeavors to create cancer vaccines have failed to produce remarkable clinical results as a result of substantial obstacles, such as the suppression of the tumor immune microenvironment, the identification of suitable candidates, the assessment of immune responses, and the acceleration of vaccine production. Hence, there are possibilities for the industry to overcome challenges and enhance patient results in the coming years. This can be achieved by recognizing the intricate nature of clinical issues and continuously working toward surpassing existing limitations.

Emerging strategies in lymph node-targeted nano-delivery systems for tumor immunotherapy

The emergence of immunotherapy has led to the clinical approval of several related drugs. However, their efficacy against solid tumors remains limited. As the hub of immune activation, lymph nodes (LNs) play a critical role in tumor immunotherapy by initiating and amplifying immune responses. Nevertheless, the intricate physiological structure and barriers within LNs, combined with the immunosuppressive microenvironment induced by tumor cells, significantly impede the therapeutic efficacy of immunotherapy. Engineered nanoparticles (NPs) have shown great potential in overcoming these challenges by facilitating targeted drug transport to LNs and directly or indirectly activating T cells. This review systematically examines the structural features of LNs, key factors influencing the targeting efficiency of NPs, and current strategies for remodeling the immunosuppressive microenvironment of LNs. Additionally, it discusses future opportunities for optimizing NPs to enhance tumor immunotherapy, addressing challenges in clinical translation and safety evaluation.

Involvement of naïve T cells in the pathogenesis of osimertinib-induced pneumonitis

Osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, effectively treats EGFR-mutated non-small cell lung cancer. Drug-induced interstitial lung disease, a potentially fatal complication of osimertinib, involves an increase in lymphocytes in the bronchoalveolar lavage fluid (BALF). As the precise role of these lymphocytes is unknown, we investigated the pathogenesis of osimertinib-induced pneumonitis using BALF obtained from patients, and an osimertinib-induced pneumonitis mouse model. Mass cytometry revealed the presence of CCR7+ CD45RA+ naïve T cells in the BALF of patients with osimertinib-induced pneumonitis. Body weight measurements, BALF analysis, histopathological evaluation and RNA sequencing of mouse lung tissue were performed to investigate immune cell involvement and the mechanisms underlying osimertinib-induced pneumonitis. In the mouse model, administration of osimertinib after naphthalene-induced damage to the bronchiolar epithelium exacerbated lung inflammation and resulted in significant weight loss. Immunofluorescence staining revealed the infiltration of CCR7+ cells into the lungs of mice treated with naphthalene and osimertinib. Bulk RNA sequencing identified an upregulation of chemokine-related biological processes, with increased expression of C-C motif chemokine ligand 21 (Ccl21) and C-C motif chemokine ligand 8 (Ccl8) in the lung tissue. Additionally, immunofluorescence staining confirmed elevated expression of Ccl21 and Ccl8 in the distal bronchiolar epithelium. This study provides insights into the mechanisms underlying osimertinib-induced pneumonitis.

Manganese-Driven Plasmid Nanofibers Formed In Situ for Cancer Gene Delivery and Metalloimmunotherapy

While nucleic-acid-based cancer vaccines hold therapeutic potential, their limited immunogenicity remains a challenge due in part to the low efficiency of cytoplasmic delivery caused by lysosomal entrapment. In this work, we found that plasmids encoding both an antigen and a STING agonist protein adjuvant can self-assemble into coordination nanofibers, triggered by manganese ions. We developed a strategy to construct a DNA vaccine, termed MnO2-OVA-CDA-mem, formed by the coencapsulation of manganese dioxide (MnO2), an antigen-expressing plasmid (encoding ovalbumin, OVA), and an adjuvant enzyme-expressing plasmid (encoding STING agonist, CDA) within dendritic cell (DC) membranes. Upon uptake into acidic lysosomes, Mn2+ released from MnO2 triggered the nucleic acids to undergo a morphological change from nanospheres (∼180 nm diameter) to nanofibers (∼1 μm length), resulting in an increase in mechanical strength by about 9-fold and consequently lysosomal membrane disruption. The antigen OVA and adjuvants Mn2+ and CDA in the cytoplasm triggered strong DC activation and antigen-specific CD8+ T cell metalloimmune responses, significantly inhibiting the growth of B16-OVA tumors and inducing long-term immune memory. Altogether, MnO2-OVA-CDA-mem holds potential as a platform for nucleic acid antigen and adjuvant delivery using an in situ self-assembly strategy in a metal-driven, stimulus-responsive, and programmable manner for cancer metalloimmunotherapy.

A novel peptide targeting CCR7 inhibits tumor cell lymph node metastasis

Lymph nodes are the most common metastasis sites for tumor cells, which are intimately linked to patient prognosis. It has been reported that cancer cells can upregulate CC Chemokine Receptor 7 (CCR7) expression and hijack its normal functions, enabling them to migrate along the gradient of CCL19 and CCL21 toward the lymph nodes and colonies as the initial stage of distant metastasis. In tumor patients, the metastatic tumor in the lymph nodes exhibited higher expression of CCR7, as well as inhibitory immune checkpoints PD-1, LAG-3, and TIM-3 compared to the primary tumors with the analysis of TCGA and GEO databases. Also, in mouse tumor model, tumor cells with elevated CCR7 expression were more susceptible to develop popliteal lymph node metastasis. Subsequently, we successfully identified a CCR7 binding peptide TC6 by phage display biopanning, which specifically blocks the interaction of CCR7/CCL19 and CCR7/CCL21. Further, the D-amino acids were introduced to substitute the N- and C-terminus of TC6 peptide to obtain the proteolysis-resistant TC6-D3 peptide, which decreased tumor cell migration in vitro via ERK1/2 pathway and inhibited tumor growth and lymph nodes metastasis in vivo, as well as effectively restored T cells cytotoxicity in both primary tumors and lymph nodes. In conclusion, CCR7 promoted tumor cell metastasis to lymph node and inhibited the anti-tumor immune responses in lymph nodes. Specific blockade of the CCR7 pathway with TC6-D3 peptide can significantly reduce lymph node tumor burden, promoting CD8+ T cell infiltration in primary tumors, meanwhile, enhancing anti-tumor immune responses in lymph nodes.

Meningeal lymphatic vessel crosstalk with central nervous system immune cells in aging and neurodegenerative diseases

Meningeal lymphatic vessels form a relationship between the nervous system and periphery, which is relevant in both health and disease. Meningeal lymphatic vessels not only play a key role in the drainage of brain metabolites but also contribute to antigen delivery and immune cell activation. The advent of novel genomic technologies has enabled rapid progress in the characterization of myeloid and lymphoid cells and their interactions with meningeal lymphatic vessels within the central nervous system. In this review, we provide an overview of the multifaceted roles of meningeal lymphatic vessels within the context of the central nervous system immune network, highlighting recent discoveries on the immunological niche provided by meningeal lymphatic vessels. Furthermore, we delve into the mechanisms of crosstalk between meningeal lymphatic vessels and immune cells in the central nervous system under both homeostatic conditions and neurodegenerative diseases, discussing how these interactions shape the pathological outcomes. Regulation of meningeal lymphatic vessel function and structure can influence lymphatic drainage, cerebrospinal fluid-borne immune modulators, and immune cell populations in aging and neurodegenerative disorders, thereby playing a key role in shaping meningeal and brain parenchyma immunity.

Sodium nitrite orchestrates macrophage mimicry of tongue squamous carcinoma cells to drive lymphatic metastasis

BACKGROUND

Tongue squamous cell carcinoma (TSCC) is a malignant oral cancer with unclear pathogenesis that shows a tendency for early-stage lymphatic metastasis. This results in a poor prognosis, with a low 5-year survival rate. Dietary sodium nitrite (NaNO2) has proposed associations with disease, including cancer. However, a direct relationship between NaNO2 and TSCC has not been established.

METHODS

In vitro and in vivo assays were used to investigate the role of NaNO2 in TSCC. Protein expression in TSCC specimens was detected by immunohistochemistry and immunofluorescence. The molecular mechanism was determined using RT-qPCR, western blot, RNA-seq, luciferase reporter assays, migration assays, and FACS analysis. More detail of methods can be found in the Materials and methods section.

RESULTS

The data in this study showed that NaNO2 did not initiate carcinogenesis in the tongue but improved the lymphatic metastatic potential of TSCC cells in the specified experimental period. During metastasis to lymph nodes, monocyte-macrophage markers were upregulated in TSCC cells, whereas keratin markers were downregulated. Specifically, expression of the CD68 gene was high in TSCC cells following NaNO2-induced TSCC phenotypic switching. These phenotypic changes were associated with activation of transcription factor cyclic-AMP response binding protein (CREB1), which directly targets CD68 transcription. Furthermore, blocking CREB1 activity either through gene knockout or specific inhibitor treatment decreased the migration ability of TSCC cells and suppressed CD68 expression.

CONCLUSIONS

Our findings highlight the role of NaNO2 in enabling macrophage mimicry in TSCC cells through the CREB1-CD68 signaling pathway, which promotes lymphatic metastasis. Shedding light on drivers of lymphatic metastasis in TSCC and providing a new perspective on dietary strategies to improve outcomes of patients with TSCC.

A novel anti-mouse CCR7 monoclonal antibody, C7Mab-7, demonstrates high sensitivity in flow cytometry, western blot, and immunohistochemistry

C-C chemokine receptor type 7 (CCR7) is a member of the G protein-coupled receptor family and functions as a lymph node-homing receptor for immune cells. Upon ligand binding, CCR7 promotes the migration of immune cells to secondary lymphoid organs. In cancers, CCR7 has been revealed as a critical molecule in lymph node metastasis. Consequently, anti-CCR7 monoclonal antibodies (mAbs) have been developed as cancer therapeutic agents. In this study, we established an anti-mouse CCR7 (mCCR7) mAb, C7Mab-7 (rat IgG1, kappa) using the Cell-Based Immunization and Screening (CBIS) method. C7Mab-7 demonstrated high sensitivity in flow cytometry. The dissociation constant (K D) value of C7Mab-7 was determined to be 2.5 × 10⁻⁹ M for mCCR7-overexpressed Chinese hamster ovary-K1 (CHO/mCCR7) cells. Furthermore, C7Mab-7 detected mCCR7 with high sensitivity in western blot and immunohistochemistry. C7Mab-7, developed by the CBIS method, accelerates the development of CCR7-targeted antibody therapies and cancer diagnostics.

Beyond CCR7: dendritic cell migration in type 2 inflammation

Conventional dendritic cells (cDCs) are crucial antigen-presenting cells that initiate and regulate T cell responses, thereby shaping immunity against pathogens, innocuous antigens, tumors, and self-antigens. The migration of cDCs from peripheral tissues to draining lymph nodes (dLNs) is essential for their function in immune surveillance. This migration allows cDCs to convey the conditions of peripheral tissues to antigen-specific T cells in the dLNs, facilitating effective immune responses. Migration is primarily mediated by chemokine receptor CCR7, which is upregulated in response to homeostatic and inflammatory cues, guiding cDCs to dLNs. However, during type 2 immune responses, such as those triggered by parasites or allergens, a paradox arises-cDCs exhibit robust migration to dLNs despite low CCR7 expression. This review discusses how type 2 inflammation relies on additional signaling pathways, including those induced by membrane-derived bioactive lipid mediators like eicosanoids, sphingolipids, and oxysterols, which cooperate with CCR7 to enhance cDC migration and T helper 2 (Th2) differentiation. We explore the potential regulatory mechanisms of cDC migration in type 2 immunity, offering insights into the differential control of cDC trafficking in diverse immune contexts and its impact on immune responses.

A Fluorescent Probe Enables the Discovery of Improved Antagonists Targeting the Intracellular Allosteric Site of the Chemokine Receptor CCR7

Intracellular ligands of G protein-coupled receptors (GPCRs) are gaining significant interest in drug discovery. Here, we report the development of the fluorescent ligand Mz437 (4) targeting the CC chemokine receptor CCR7 at an intracellular allosteric site. We demonstrate its experimental power by applying 4 to identify two improved intracellular CCR7 antagonists, SLW131 (10) and SLW132 (21m), developed by converting two weakly active antagonists into single- or double-digit nanomolar ligands with minimal modifications. The thiadiazoledioxide 10 was derived from the CCR7 antagonist Cmp2105 by removing a methyl group from the benzamide moiety, while the squaramide 21m was obtained from the CXCR1/CXCR2 antagonist and clinical candidate navarixin by replacing the ethyl substituent by a tert-butyl group to engage a lipophilic subpocket. We show that 10 and 21m qualify to probe CCR7 biology in recombinant and primary immune cells and expect our novel probes to facilitate the design of next-generation intracellular CCR7 ligands.

Endosomal chemokine receptor signalosomes regulate central mechanisms underlying cell migration

Chemokine receptors are GPCRs that regulate the chemotactic migration of a wide variety of cells including immune and cancer cells. Most chemokine receptors contain features associated with the ability to stimulate G protein signaling during β-arrestin-mediated receptor internalization into endosomes. As endosomal signaling of certain non-GPCR receptors plays a major role in cell migration, we chose to investigate the potential role of endosomal chemokine receptor signaling on mechanisms governing this function. Applying a combination of pharmacological and cell biological approaches, we demonstrate that the model chemokine receptor CCR7 recruits G protein and β-arrestin simultaneously upon chemokine stimulation, which enables internalized receptors to activate G protein from endosomes. Furthermore, spatiotemporal-resolved APEX2 proteome profiling shows that endosomal CCR7 uniquely enriches specific Rho GTPase regulators as compared to plasma membrane CCR7, which is directly associated with enhanced activity of the Rho GTPase Rac1 and chemotaxis of immune T cells. As Rac1 drives the formation of membrane protrusions during chemotaxis, our findings suggest an important integrated function of endosomal chemokine receptor signaling in cell migration.

Inflammation switches the chemoattractant requirements for naive lymphocyte entry into lymph nodes

Sustained lymphocyte migration from blood into lymph nodes (LNs) is important for immune responses. The CC-chemokine receptor-7 (CCR7) ligand CCL21 is required for LN entry but is downregulated during inflammation, and it has been unclear how recruitment is maintained. Here, we show that the oxysterol biosynthetic enzyme cholesterol-25-hydroxylase (Ch25h) is upregulated in LN high endothelial venules during viral infection. Lymphocytes become dependent on oxysterols, generated through a transcellular endothelial-fibroblast metabolic pathway, and the receptor EBI2 for inflamed LN entry. Additionally, Langerhans cells are an oxysterol source. Ch25h is also expressed in inflamed peripheral endothelium, and EBI2 mediates B cell recruitment in a tumor model. Finally, we demonstrate that LN CCL19 is critical in lymphocyte recruitment during inflammation. Thus, our work explains how naive precursor trafficking is sustained in responding LNs, identifies a role for oxysterols in cell recruitment into inflamed tissues, and establishes a logic for the CCR7 two-ligand system.

Viral Infection and Dissemination Through the Lymphatic System

Many viruses induce viremia (virus in the blood) and disseminate throughout the body via the bloodstream from the initial infection site. However, viruses must often pass through the lymphatic system to reach the blood. The lymphatic system comprises a network of vessels distinct from blood vessels, along with interconnected lymph nodes (LNs). The complex network has become increasingly appreciated as a crucial host factor that contributes to both the spread and control of viral infections. Viruses can enter the lymphatics as free virions or along with migratory cells. Once virions arrive in the LN, sinus-resident macrophages remove infectious virus from the lymph. Depending on the virus, macrophages can eliminate infection or propagate the virus. A virus released from an LN is eventually deposited into the blood. This unique pathway highlights LNs as targets for viral infection control and for modulation of antiviral response development. Here, we review the lymphatic system and viruses that disseminate through this network. We discuss infection of the LN, the generation of adaptive antiviral immunity, and current knowledge of protection within the infected node. We conclude by sharing insights from ongoing efforts to optimize lymphatic targeting by vaccines and pharmaceuticals. Understanding the lymphatic system's role during viral infection enhances our knowledge of antiviral immunity and virus-host interactions and reveals potential targets for next-generation therapies.

CCR7A defines a subpopulation of IgD+IgM- B cells with higher IgD secreting capacity in the rainbow trout skin

B cells exclusively expressing IgD on the cell surface (IgD+IgM- B cells) have been identified in mammals, where they seem to play a still not well-defined role in peripheral tolerance. These cells have also been reported in catfish (Ictalurus punctatus) peripheral blood and in several mucosal tissues of rainbow trout (Oncorhynchus mykiss), including gut, gills and skin. As in mammals, the precise function of these cells remains obscure, yet, in rainbow trout mucosal surfaces, these cells have been shown to be differentiated to plasma-like cells. Interestingly, in the gills, these IgD+IgM- B cells expressed high levels of the CC chemokine receptor 7 (CCR7), receptor that in mammals controls the migration of B and T cells to secondary lymphoid organs. In this work, we have established that this is also true for the trout skin, where CCR7 defines a specific subset of IgD+IgM- B cells that are further differentiated to a plasma-like profile than those not expressing CCR7. These findings increase the current understanding of this enigmatic B cell population and point to CCR7 as a key differentiation marker for these cells.

Glymphatic system: a self-purification circulation in brain

The glymphatic system theory introduces a new perspective on fluid flow and homeostasis in the brain. Here, cerebrospinal fluid and interstitial fluid (CSF-ISF) moves from the perivascular spaces (PVS) of arteries to those of veins for drainage. Aquaporin-4 (AQP4) plays a crucial role in driving fluid within the PVS. The impairment to AQP4 is closely linked to the dysfunction of the glymphatic system. The function of the glymphatic system is less active during waking but enhanced during sleep. The efficiency of the glymphatic system decreases with aging. Damage to the glymphatic system will give rise to the development and progression of many brain diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), chronic traumatic encephalopathy (CTE), and vascular dementia (VaD). Here, we reviewed previous research associated with the glymphatic system, including its concepts, principles, and influencing factors. We hypothesize that AQP4 could be a target for the prevention and treatment of certain brain diseases through the regulation on the glymphatic system.

Utility of CCR7 to differentiate classic Hodgkin lymphoma and other B-cell lymphomas by flow cytometry and immunohistochemistry

OBJECTIVES

Classic Hodgkin lymphoma (CHL) is characterized by infrequent neoplastic Hodgkin and Reed-Sternberg (HRS) cells in an inflammatory background. The diagnostic utility of CC-chemokine receptor 7 (CCR7) in CHL was explored using flow cytometry and immunohistochemistry (IHC).

METHODS

Neoplastic specimens and non-neoplastic lymph nodes were immunophenotyped and CCR7 expression was measured semiquantitatively by flow cytometry (clone 3D12) and IHC (clone 150503).

RESULTS

Our results showed that CCR7 was expressed on HRS cells in the vast majority of CHL cases (45/48 by flow cytometry, 57/59 by IHC) but rarely expressed in neoplastic cells in diffuse large B-cell lymphoma, not otherwise specified (1/25 by flow cytometry, 2/40 by IHC) and nodular lymphocyte predominant Hodgkin lymphoma (0/4 by flow cytometry, 1/13 by IHC). Primary mediastinal large B-cell lymphoma (PMLBCL) revealed weak CCR7 expression by flow cytometry in most cases (8/10) but only occasionally by IHC (2/12). Both cases (2/2) of T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) also showed CCR7 expression detected by flow cytometry compared with IHC (0/7). The HRS cells demonstrated a greater percentage of positive cells and greater antigen intensity than the other B-cell lymphomas by IHC. The expression identified by flow cytometry in PMLBCL and THRLBCL but not by IHC suggests that there may be differences in the detection capabilities of the 2 techniques or the 2 CCR7 clones used.

CONCLUSIONS

The expression of CCR7 in HRS cells suggests its potential utility in differentiating CHL from other B-cell lymphomas. Incorporating CCR7 into flow cytometry and IHC panels may further enhance the diagnostic sensitivity of CHL.

Characteristics of a CCL21 Gene-Modified Dendritic Cell Vaccine Utilized for a Clinical Trial in Non-Small Cell Lung Cancer

The treatment of non-small cell lung cancer has made major strides with the use of immune checkpoint inhibitors; however, there remains a significant need for therapies that can overcome immunotherapy resistance. Dendritic cell (DC) vaccines have been proposed as a therapy that can potentially enhance the antitumor immune response. We have embarked on a phase I clinical trial of a vaccine consisting of monocyte-derived DCs (moDC) modified to express the chemokine C-C motif chemokine ligand 21 (CCL21-DC) given in combination with pembrolizumab. In this study, we report a comprehensive characterization of this CCL21-DC vaccine and interrogate the effects of multiple factors in the manufacturing process. We show that the cellular makeup of the CCL21-DC vaccine is heterogeneous because of the presence of passenger lymphocytes at a proportion that is highly variable among patients. Single-cell RNA sequencing of vaccines revealed further heterogeneity within the moDC compartment, with cells spanning a spectrum of DC phenotypes. Transduction with a CCL21-containing adenoviral vector augmented CCL21 secretion by moDCs, but otherwise had a minimal effect on vaccine characteristics. A single freeze-thaw cycle for stored vaccines was associated with minor alterations to the DC phenotype, as was the use of healthy donors rather than patient autologous blood. Our results highlight important considerations for the production of DC vaccines and identify underexplored factors that may affect their efficacy and immunologic impact.

Integrating single-cell RNA and T cell/B cell receptor sequencing with mass cytometry reveals dynamic trajectories of human peripheral immune cells from birth to old age

A comprehensive understanding of the evolution of the immune landscape in humans across the entire lifespan at single-cell transcriptional and protein levels, during development, maturation and senescence is currently lacking. We recruited a total of 220 healthy volunteers from the Shanghai Pudong Cohort (NCT05206643), spanning 13 age groups from 0 to over 90 years, and profiled their peripheral immune cells through single-cell RNA-sequencing coupled with single T cell and B cell receptor sequencing, high-throughput mass cytometry, bulk RNA-sequencing and flow cytometry validation experiments. We revealed that T cells were the most strongly affected by age and experienced the most intensive rewiring in cell-cell interactions during specific age. Different T cell subsets displayed different aging patterns in both transcriptomes and immune repertoires; examples included GNLY+CD8+ effector memory T cells, which exhibited the highest clonal expansion among all T cell subsets and displayed distinct functional signatures in children and the elderly; and CD8+ MAIT cells, which reached their peaks of relative abundance, clonal diversity and antibacterial capability in adolescents and then gradually tapered off. Interestingly, we identified and experimentally verified a previously unrecognized 'cytotoxic' B cell subset that was enriched in children. Finally, an immune age prediction model was developed based on lifecycle-wide single-cell data that can evaluate the immune status of healthy individuals and identify those with disturbed immune functions. Our work provides both valuable insights and resources for further understanding the aging of the immune system across the whole human lifespan.

An analysis of single-cell data reveals therapeutic effects of AMG487 in experimental autoimmune uveitis

Uveitis, an ocular autoimmune disease that poses a significant threat to vision, is caused by immune cells erroneously attacking retinal cells and currently lacks specific and effective therapeutic interventions. The CXC chemokine receptor 3 (CXCR3) facilitates the migration of immune cells to sites of inflammation. AMG487, a CXCR3 antagonist, holds potential for treating autoimmune diseases by blocking immunes cells chemotaxis. However, its effects and mechanisms in uveitis remain unclear. Using single-cell assay for transposase-accessible chromatin sequencing and RNA sequencing, we observed increased expression of CXCR3 and chemotactic pathways in peripheral blood of Vogt-Koyanagi-Harada patients and cervical lymph nodes of experimental autoimmune uveitis mice. AMG487 treatment in experimental autoimmune uveitis was shown to be therapeutically effective. Analysis of flow cytometry and single-cell RNA sequencing in AMG487-treated mice revealed reduced expression of inflammatory genes in immune cells. Specifically, AMG487 decreased the proportion of plasma cell in B cells, restored the ratio between effector T cells and regulatory T cells, and diminished T helper (Th) 17 cell pathogenicity by suppressing highly inflammatory granulocyte-macrophage colony-stimulating factor-producing Th17 cells while enhancing anti-inflammatory interleukin-10-producing Th17 cells. Our study presents an exhaustive single-cell transcriptional analysis of immune cells under AMG487 treatment, thereby elucidating potential mechanisms and providing a potential reference for the development of novel therapeutic strategies for autoimmune diseases.

Striking a balance: new perspectives on homeostatic dendritic cell maturation

Dendritic cells (DCs) are crucial gatekeepers of the balance between immunity and tolerance. They exist in two functional states, immature or mature, that refer to an information-sensing versus an information-transmitting state, respectively. Historically, the term DC maturation was used to describe the acquisition of immunostimulatory capacity by DCs following their triggering by pathogens or tissue damage signals. As such, immature DCs were proposed to mediate tolerance, whereas mature DCs were associated with the induction of protective T cell immunity. Later studies have challenged this view and unequivocally demonstrated that two distinct modes of DC maturation exist, homeostatic and immunogenic DC maturation, each with a distinct functional outcome. Therefore, the mere expression of maturation markers cannot be used to predict immunogenicity. How DCs become activated in homeostatic conditions and maintain tolerance remains an area of intense debate. Several recent studies have shed light on the signals driving the homeostatic maturation programme, especially in the conventional type 1 DC (cDC1) compartment. Here, we highlight our growing understanding of homeostatic DC maturation and the relevance of this process for immune tolerance.

Chemotherapy-induced cellular senescence promotes stemness of aggressive B-cell non-Hodgkin's lymphoma via CCR7/ARHGAP18/IKBα signaling activation

BACKGROUND

Resistance to existing therapies is a major cause of treatment failure in patients with refractory and relapsed B-cell non-Hodgkin's lymphoma (r/r B-NHL). Therapy-induced senescence (TIS) is one of the most important mechanisms of drug resistance.

METHODS

This study used single-cell RNA sequencing to analyze doxorubicin-induced senescent B-NHL cells. C-C chemokine receptor 7 (CCR7) expression in patients with aggressive B-NHL was assessed using immunohistochemistry and flow cytometry. Lentiviral transfection was used to target CCR7 expression in Raji and SU-DHL-2 cells. Protein localization was visualized through immunofluorescence, while western blotting and co-immunoprecipitation were used to analyze protein expression and interactions. Cell proliferation was measured with the Cell Counting Kit-8 assay, and senescent cells were detected using senescence-associated β-galactosidase staining. The stemness of cells was evaluated through colony and sphere formation assays. Transwell assays assessed cell migration and invasion. Finally, inhibitors GS143 and Y27632 were used to examine the effect of IKBα and ARHGAP/RhoA inhibition on B-NHL-TIS.

RESULTS

Here we identified a distinct group of TIS, composed of memory B-cell population characterized by strong positive expression of CCR7, which was significantly elevated in TIS population compared with normal proliferating and autonomously senescent lymphoma cell populations. Additionally, CCR7 expression was significantly upregulated in patients with r/r B-NHL, and was an independent prognostic factor in B-NHL, with high CCR7 expression being strongly associated with poor prognosis. In vitro results indicated that CCL21 induced migration and invasion of B-NHL cells via CCR7, while blocking CCR7 reduced doxorubicin-induced migration and invasion of these cells. Furthermore, B-NHL-TIS regulated by CCR7 and exhibited enhanced phenotypic and functional stemness features, including the upregulation of stemness markers, increased colony-forming, invasive and migratory capabilities. Mechanistically, blocking CCR7 reversed the stemness characteristics of senescent B-NHL cells by inhibiting the activation of ARHGAP18/IKBα signaling.

CONCLUSIONS

Together, TIS promotes the stemness of B-NHL cells via CCR7/ARHGAP18/IKBα signaling activation and targeting CCR7/ARHGAP18 might overcome the chemoresistance of senescent B-NHL cells by inhibiting stemness acquisition and maintenance.

Role of tertiary lymphoid structures and B cells in clinical immunotherapy of gastric cancer

Gastric cancer is a common malignant tumor of the digestive tract, and its treatment remains a significant challenge. In recent years, the role of various immune cells in the tumor microenvironment in cancer progression and treatment has gained increasing attention. Immunotherapy, primarily based on immune checkpoint inhibitors, has notably improved the prognosis of patients with gastric cancer; however, challenges regarding therapeutic efficacy persist. Histological features within the tumor microenvironment, such as tertiary lymphoid structures (TLSs), tumor-infiltrating lymphocytes, and the proportion of intratumoral stroma, are emerging as potentially effective prognostic factors. In gastric cancer, TLSs may serve as local immune hubs, enhancing the ability of immune cells to interact with and recognize tumor antigens, which is closely linked to the effectiveness of immunotherapy and improved survival rates in patients. However, the specific cell type driving TLS formation in tumors has not yet been elucidated. Mature TLSs are B-cell regions containing germinal centers. During germinal center formation, B cells undergo transformations to become mature cells with immune function, exerting anti-tumor effects. Therefore, targeting B cells within TLSs could provide new avenues for gastric cancer immunotherapy. This review, combined with current research on TLSs and B cells in gastric cancer, elaborates on the relationship between TLSs and B cells in the prognosis and immunotherapy of patients with gastric cancer, aiming to provide effective guidance for precise immunotherapy.

T Cell Development: From T-Lineage Specification to Intrathymic Maturation

T cell development occurs in the thymus in both mice and humans. Upon entry into the thymus, bone marrow-derived blood-borne progenitors receive instructive signals, including Notch signaling, to eliminate their potential to develop into alternative immune lineages while committing to the T cell fate. Upon T-lineage commitment, developing T cells receive further instructional cues to generate different T cell sublineages, which together possess diverse immunological functions to provide host immunity. Over the years, numerous studies have contributed to a greater understanding of key thymic signals that govern T cell differentiation and subset generation. Here, we review these critical signaling factors that govern the different stages of both mouse and human T cell development, while also focusing on the transcriptional changes that mediate T cell identity and diversity.

Spatiotemporal Cellular Dynamics of Germinal Center Reaction in Coronavirus Disease 2019 Lung-Draining Lymph Node Based on Imaging-Based Spatial Transcriptomics

Although lymph node structures may be compromised in severe SARS-CoV-2 infection, the extent and parameters of recovery in convalescing patients remain unclear. Therefore, this study aimed to elucidate the nuances of lymphoid structural recovery and their implications for immunologic memory in nonhuman primates infected with SARS-CoV-2. To do so, we utilized imaging-based spatial transcriptomics to delineate immune cell composition and tissue architecture formation in the lung-draining lymph nodes during primary infection, convalescence, and reinfection from COVID-19. We noted the establishment of a germinal center with memory B cell differentiation within lymphoid follicles during convalescence accompanied by contrasting transcriptome patterns indicative of the acquisition of follicular helper T cells versus the loss of regulatory T cells. Additionally, repopulation of germinal center-like B cells was observed in the medullary niche with accumulating plasma cells along with enhanced transcriptional expression of B cell-activating factor receptor over the course of reinfection. The spatial transcriptome atlas produced herein enhances our understanding of germinal center formation with immune cell dynamics during COVID-19 convalescence and lymphoid structural recovery with transcriptome dynamics following reinfection. These findings have the potential to inform the optimization of vaccine strategies and the development of precise therapeutic interventions in the spatial context.

Vaccine approaches to treat urothelial cancer

Bladder cancer (BC) accounts for about 4% of all malignancies. Non-muscle-invasive BC, 75% of cases, is treated with transurethral resection and adjuvant intravesical instillation, while muscle-invasive BC warrants cisplatin-based perioperative chemotherapy. Although immune-checkpoint inhibitors, antibody drug conjugates and targeted agents have provided dramatic advances, metastatic BC remains a generally incurable disease and clinical trials continue to vigorously evaluate novel molecules. Cancer vaccines aim at activating the patient's immune system against tumor cells. Several means of delivering neoantigens have been developed, including peptides, antigen-presenting cells, virus, or nucleic acids. Various improvements are constantly being explored, such as adjuvants use and combination strategies. Nucleic acids-based vaccines are increasingly gaining attention in recent years, with promising results in other malignancies. However, despite the recent advantages, numerous obstacles persist. This review is aimed at describing the different types of cancer vaccines, their evaluations in UC patients and the more recent innovations in this field.

Single-cell RNA-sequencing of human spleens reveals an IDO-1+ tolerogenic dendritic cell subset in pancreatic cancer patients that is absent in normal individuals

Local and systemic immunosuppression are prominent features of pancreatic cancer, rendering anti-tumor effector cells inactive and immunotherapeutic approaches ineffective. The spleen, an understudied point of antigen-presentation and T cell priming in humans, holds particular importance in pancreatic cancer due to its proximity to the developing tumor. As main effectors of antigen presentation, dendritic cells display antigens to lymphocytes, thereby bridging the innate and adaptive immune response. While tumor-infiltrating anti-inflammatory dendritic cells have been described, splenic dendritic cells have historically just been considered to stimulate the anti-tumor immune response. Here, we describe, for the first time, the presence of an immunosuppressive, tolerogenic IDO1+ dendritic cell subset in the spleens of pancreatic cancer patients that likely contributes to systemic immunosuppression that is associated with pancreatic ductal adenocarcinoma. Network analysis of scRNA seq data reveals extensive communication networks between the identified tolerogenic DC cluster and numerous immune cell populations in the spleen. Interactions with innate and adaptive immune cells suggest a broad influence on leukocyte trafficking and immune regulation within the spleen microenvironment. The identification of signaling pathways involving AHR and IDO-1, CCL19, NECTIN2, CLEC2D, and others elucidates potential mechanisms underlying the immunosuppressive functions of this cell type.

Local cell therapy using CCL19-expressing allogeneic mesenchymal stem cells exerts robust antitumor effects by accumulating CD103+ IL-12-producing dendritic cells and priming CD8+ T cells without involving draining lymph nodes

BACKGROUND

Immune checkpoint blockade is a promising anticancer therapy, whereas the presence of T cells in tumor sites is indispensable for its therapeutic efficacy. To promote the infiltration of T cells and dendritic cells (DCs) into the tumor, we previously proposed a local cell therapy using chemokine (C-C motif) ligand 19 (CCL19)-expressing immortalized syngeneic immortalized mesenchymal stem cells (syn-iMSC/CCL19). However, the preparation of syngeneic/autologous MSC from individual hosts limits the clinical application of this cell therapy.

METHODS

In this study, we further developed a new cell therapy using allogeneic iMSC/CCL19 (allo-iMSC/CCL19) using several tumor mice models.

RESULTS

The allo-iMSC/CCL19 therapy exerted drastic antitumor effects, in which the host's T cells were induced to respond to allogeneic MSC. In addition, the allo-iMSC/CCL19 therapy promoted the infiltration of CD103+ interleukin (IL)-12-producing DCs and priming of CD8+ T cells at tumor sites compared with that using syn-iMSC/CCL19. The antitumor effect of allo-iMSC/CCL19 therapy was not influenced by fingolimod, a sphingosine 1-phosphate receptor modulator, implying no involvement of draining lymph nodes in the priming of tumor-specific T cells.

CONCLUSION

These results suggest that allo-iMSC/CCL19 therapy exerts dramatic antitumor effects by promoting the infiltration of CD103+ IL-12-producing DCs and thereby priming tumor-specific CD8+ T cells at tumor sites. This local cell therapy could be a promising approach to anticancer therapy, particularly for overcoming dysfunction in the cancer-immunity cycle.

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.

Multimodal profiling of biostabilized human skin modules reveals a coordinated ecosystem response to injected mRNA-1273 COVID-19 vaccine

BACKGROUND

The field of drug development is witnessing a remarkable surge in the development of innovative strategies. There is a need to develop technological platforms capable of generating human data prior to progressing to clinical trials.

METHODS

Here we introduce a new flexible solution designed for the comprehensive monitoring of the natural human skin ecosystem's response to immunogenic drugs over time. Based on unique bioengineering to preserve surgical resections in a long survival state, it allows for the first time a comprehensive analysis of resident immune cells response at both organ and single-cell levels.

RESULTS

Upon injection of the mRNA-1273 COVID-19 vaccine, we characterized precise sequential molecular events triggered upon detection of the exogenous substance. The vaccine consistently targets DC/macrophages and mast cells, regardless of the administration route, while promoting specific cell-cell communications in surrounding immune cell subsets.

CONCLUSION

Given its direct translational relevance, this approach provides a multiscale vision of genuine human tissue immunity that could pave the way toward the development of new vaccination and drug development strategies.

Investigating the causal relationship between inflammation and multiple types of hearing loss: a multi-omics approach combining Mendelian randomization and molecular docking

Background

Hearing loss affects over 10% of the global population. Inflammation is a key factor in hearing loss caused by noise, infection, and aging, damaging various hearing-related tissues (e.g., spiral ligament, stria vascularis). Mendelian randomization (MR) can help identify potential causal relationships and therapeutic targets.

Methods

We conducted MR analyses on 91 inflammatory proteins (n = 14,824) and genome-wide association study results for various hearing loss types in European ancestry populations, including sensorineural hearing loss (SNHL; ncases = 15,952, ncontrols = 196,592), sudden idiopathic hearing loss (SIHL; ncases = 1,491, ncontrols = 196,592), and other hearing loss (OHL; ncases = 4,157, ncontrols = 196,592). Additionally, hearing loss with difficulty in hearing (ncases = 14,654, ncontrols = 474,839) served as a validation set. To predict inflammatory protein-enriched pathways and tissues, we performed enrichment analysis, functional annotation, and tissue analyses using "OmicsNet2.0" and "FUMA" platforms. We also combined "CoreMine" and molecular docking to explore potential drugs targeting inflammatory proteins and investigate binding efficacy.

Results

CCL19 was identified as a common risk factor for SNHL and OHL, which was validated in the hearing loss with difficulty in hearing dataset. Tissue analysis revealed that SIHL-related inflammatory proteins were enriched in the amygdala. Multi-omics research indicated associations between inflammatory proteins and neurodegenerative diseases. Molecular docking studies suggested that Chuanxiong Rhizoma and Uncariae Ramulus Cumuncis are potential drugs for targeting CCL19.

Conclusion

This study identified CCL19 as a common risk factor for various types of hearing loss through MR analysis, highlighting the crucial role of inflammatory proteins in hearing loss. The enrichment of related inflammatory proteins in the amygdala and their association with neurodegenerative diseases provide new insights into the mechanisms of hearing loss.

Brain-immune interactions: implication for cognitive impairments in Alzheimer's disease and autoimmune disorders

Progressive memory loss and cognitive dysfunction, encompassing deficits in learning, memory, problem solving, spatial reasoning, and verbal expression, are characteristics of Alzheimer's disease and related dementia. A wealth of studies has described multiple roles of the immune system in the development or exacerbation of dementia. Individuals with autoimmune disorders can also develop cognitive dysfunction, a phenomenon termed "autoimmune dementia." Together, these findings underscore the pivotal role of the neuroimmune axis in both Alzheimer's disease and related dementia and autoimmune dementia. The dynamic interplay between adaptive and innate immunity, both in and outside the brain, significantly affects the etiology and progression of these conditions. Multidisciplinary research shows that cognitive dysfunction arises from a bidirectional relationship between the nervous and immune systems, though the specific mechanisms that drive cognitive impairments are not fully understood. Intriguingly, this reciprocal regulation occurs at multiple levels, where neuronal signals can modulate immune responses, and immune system-related processes can influence neuronal viability and function. In this review, we consider the implications of autoimmune responses in various autoimmune disorders and Alzheimer's disease and explore their effects on brain function. We also discuss the diverse cellular and molecular crosstalk between the brain and the immune system, as they may shed light on potential triggers of peripheral inflammation, their effect on the integrity of the blood-brain barrier, and brain function. Additionally, we assess challenges and possibilities associated with developing immune-based therapies for the treatment of cognitive decline.

Ellagic acid ameliorates alcohol-induced cognitive and social dysfunction through the gut microbiota-mediated CCL21-CCR7 axis

Chronic alcohol consumption disrupts the balance of the gut microbiome, resulting in alcohol-induced cognitive and social dysfunction (AICSD), and serves as a primary etiological factor for early-onset dementia. Ellagic acid (EA) is a polyphenolic compound belonging to the ellagitannin family, showing potential as a dietary intervention for alleviating cognitive impairments. Nonetheless, the protective effects and underlying mechanisms of EA on AICSD remain unclear. In our study, we employed a multi-omics approach to elucidate the microbiome-mediated mechanism underlying the beneficial effects of EA on AICSD. Firstly, our findings demonstrate that EA significantly ameliorated cognitive and social behavioral deficits as well as neuroinflammation induced by alcohol. Moreover, RNA-seq analysis of hippocampi indicates that EA regulated the KEGG pathway of cytokine-cytokine receptor interaction signaling by downregulating the CCL21-CCR7 axis. Furthermore, we observed that EA effectively restored the dysbiosis of gut microbiota and their derived metabolites induced by chronic alcohol consumption. Strong connections were observed between EA-regulated genes, microbiota and metabolites. Finally, the causal relationship between the microbiome and behavioral changes was further confirmed through antibiotic treatment and fecal microbiota transplantation experiments. Overall, our study provides innovative evidence supporting the role of EA in improving AICSD via regulation of the cytokine-cytokine receptor interaction signaling pathway through the microbiota-mediated CCl21-CCR7 axis. These findings offer valuable insights into both EA-based interventions as well as microbial interventions against AICSD.

C-C chemokine receptor type 7 (CCR7) regulates hepatic CD8 + T cell homeostasis and response to acute liver injury

BACKGROUND AND AIMS

Acute liver failure (ALF) is a rare but life-threatening condition, and DILI, particularly acetaminophen toxicity, is the leading cause of ALF. Innate immune mechanisms further perpetuate liver injury, while the role of the adaptive immune system in DILI-related ALF is unclear.

APPROACH AND RESULTS

We analyzed liver tissue from 2 independent patient cohorts with ALF and identified hepatic T cell infiltration as a prominent feature in human ALF. CD8 + T cells were characterized by zonation toward necrotic regions and an activated gene expression signature. In murine acetaminophen-induced liver injury, intravital microscopy revealed zonation of CD8 + but not CD4 + T cells at necrotic areas. Gene expression analysis exposed upregulated C-C chemokine receptor 7 (CCR7) and its ligand CCL21 in the liver as well as a broadly activated phenotype of hepatic CD8 + T cells. In 2 mouse models of ALF, Ccr7-/- mice had significantly aggravated early-phase liver damage. Functionally, CCR7 was not involved in the recruitment of CD8 + T cells, but regulated their activation profile potentially through egress to lymphatics. Ccr7-/- CD8 + T cells were characterized by elevated expression of activation, effector, and exhaustion profiles. Adoptive transfer revealed preferential homing of CCR7-deficient CD8 + T cells to the liver, and depletion of CD8 + T cells attenuated liver damage in mice.

CONCLUSIONS

Our study demonstrates the involvement of the adaptive immune system in ALF in humans and mice. We identify the CCR7-CCL21 axis as an important regulatory pathway, providing downstream protection against T cell-mediated liver injury.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles: A focus on inflammatory bowel disease

BACKGROUND

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as key regulators of intercellular communication, orchestrating essential biological processes by delivering bioactive cargoes to target cells. Available evidence suggests that MSC-EVs can mimic the functions of their parental cells, exhibiting immunomodulatory, pro-regenerative, anti-apoptotic, and antifibrotic properties. Consequently, MSC-EVs represent a cell-free therapeutic option for patients with inflammatory bowel disease (IBD), overcoming the limitations associated with cell replacement therapy, including their non-immunogenic nature, lower risk of tumourigenicity, cargo specificity and ease of manipulation and storage.

MAIN TOPICS COVERED

This review aims to provide a comprehensive examination of the therapeutic efficacy of MSC-EVs in IBD, with a focus on their mechanisms of action and potential impact on treatment outcomes. We examine the advantages of MSC-EVs over traditional therapies, discuss methods for their isolation and characterisation, and present mechanistic insights into their therapeutic effects through transcriptomic, proteomic and lipidomic analyses of MSC-EV cargoes. We also discuss available preclinical studies demonstrating that MSC-EVs reduce inflammation, promote tissue repair and restore intestinal homeostasis in IBD models, and compare these findings with those of clinical trials.

CONCLUSIONS

Finally, we highlight the potential of MSC-EVs as a novel therapy for IBD and identify challenges and opportunities associated with their translation into clinical practice.

HIGHLIGHTS

The source of mesenchymal stem cells (MSCs) strongly influences the composition and function of MSC-derived extracellular vesicles (EVs), affecting their therapeutic potential. Adipose-derived MSC-EVs, known for their immunoregulatory properties and ease of isolation, show promise as a treatment for inflammatory bowel disease (IBD). MicroRNAs are consistently present in MSC-EVs across cell types and are involved in pathways that are dysregulated in IBD, making them potential therapeutic agents. For example, miR-let-7a is associated with inhibition of apoptosis, miR-100 supports cell survival, miR-125b helps suppress pro-inflammatory cytokines and miR-20 promotes anti-inflammatory M2 macrophage polarisation. Preclinical studies in IBD models have shown that MSC-EVs reduce intestinal inflammation by suppressing pro-inflammatory mediators (e.g., TNF-α, IL-1β, IL-6) and increasing anti-inflammatory factors (e.g., IL-4, IL-10). They also promote mucosal healing and strengthen the integrity of the gut barrier, suggesting their potential to address IBD pathology.

Spatiotemporal control of immune responses with nucleic acid cocktail vaccine

Nucleic acid vaccines play important roles in prevention and treatment of diseases. However, limited immunogenicity remains a major obstacle for DNA vaccine applications in the clinic. To address the issue, the present study investigates a cocktail approach to DNA vaccination. In this proof-of-the-concept study, the cocktail consists of two DNAs encoding viral hemagglutinin (HA) and granulocyte-macrophage colony stimulatory factor (GM-CSF), respectively. Data from the study demonstrate that recruitment and activation of antigen-presenting cells (APCs) can be substantially improved by spatiotemporal regulation of GM-CSF and HA expressions at the site of vaccination. The types of recruited APCs and their phenotypes are also controllable by adjusting the cocktail compositions. Compared to mono-ingredient vaccine, the optimized cocktail vaccine is able to enhance the anti-viral humoral and T cell immune responses. No significant systemic inflammation has been detected after either prime or boost immunization using the cocktail vaccine. Data in the study suggest that the DNA cocktail is a safe, effective, and controllable platform for improving vaccine efficacy.

Intestinal Lymphatic Biology, Drug Delivery, and Therapeutics: Current Status and Future Directions

Historically, the intestinal lymphatics were considered passive conduits for fluids, immune cells, dietary lipids, lipid soluble vitamins, and lipophilic drugs. Studies of intestinal lymphatic drug delivery in the late 20th century focused primarily on the drugs' physicochemical properties, especially high lipophilicity, that resulted in intestinal lymphatic transport. More recent discoveries have changed our traditional view by demonstrating that the lymphatics are active, plastic, and tissue-specific players in a range of biological and pathological processes, including within the intestine. These findings have, in turn, inspired exploration of lymph-specific therapies for a range of diseases, as well as the development of more sophisticated strategies to actively deliver drugs or vaccines to the intestinal lymph, including a range of nanotechnologies, lipid prodrugs, and lipid-conjugated materials that "hitchhike" onto lymphatic transport pathways. With the increasing development of novel therapeutics such as biologics, there has been interest in whether these therapeutics are absorbed and transported through intestinal lymph after oral administration. Here we review the current state of understanding of the anatomy and physiology of the gastrointestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. We summarize the current state-of-the-art approaches to deliver drugs and quantify their uptake into the intestinal lymphatic system. Finally, and excitingly, we discuss recent examples of significant pharmacokinetic and therapeutic benefits achieved via intestinal lymphatic drug delivery. We also propose approaches to advance the development and clinical application of intestinal lymphatic delivery strategies in the future. SIGNIFICANCE STATEMENT: This comprehensive review details the understanding of the anatomy and physiology of the intestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. It highlights current state-of-the-art approaches to deliver drugs to the intestinal lymphatics and the shift toward the use of these strategies to achieve pharmacokinetic and therapeutic benefits for patients.

CCL21 Induces Plasmacytoid Dendritic Cell Migration and Activation in a Mouse Model of Glioblastoma

Dendritic cells (DCs) are professional antigen-presenting cells that are traditionally divided into two distinct subsets: myeloid DCs (mDCs) and plasmacytoid DCs (pDCs). pDCs are known for their ability to secrete large amounts of cytokine type I interferons (IFN- α). In our previous work, we have demonstrated that pDC infiltration promotes glioblastoma (GBM) tumor immunosuppression through decreased IFN-α secretion via TLR-9 signaling and increased suppressive function of regulatory T cells (Tregs) via increased IL-10 secretion, resulting in poor overall outcomes in mouse models of GBM. Further dissecting the overall mechanism of pDC-mediated GBM immunosuppression, in this study, we identified CCL21 as highly upregulated by multiple GBM cell lines, which recruit pDCs to tumor sites via CCL21-CCR7 signaling. Furthermore, pDCs are activated by CCL21 in the GBM microenvironment through intracellular signaling of β-arrestin and CIITA. Finally, we found that CCL21-treated pDCs directly suppress CD8+ T cell proliferation without affecting regulatory T cells (Tregs) differentiation, which is considered the canonical pathway of immunotolerant regulation. Taken together, our results show that pDCs play a multifaced role in GBM immunosuppression, and CCL21 could be a novel therapeutic target in GBM to overcome pDC-mediated immunosuppression.