The developmental pathway for CD103(+)CD8+ tissue-resident memory T cells of skin

Defining molecular circuits of CD8+ T cell responses in tissues during latent viral infection

Latent viral infections rely on a precise coordination of the immune response to control sporadic viral reactivation. CD8+ T cells play a crucial role in controlling viral latency by generating diverse memory responses in an epitope-specific manner. Among these distinct responses, conventional and inflationary memory responses have been described during herpesvirus infections. Using a newly generated TCR transgenic mouse strain, we investigated the transcriptomic and epigenetic remodeling of distinct epitope-specific CD8+ T cells during CMV infection across tissues at both population and single-cell levels. Our findings reveal that whereas the transcriptomic and epigenetic landscapes of conventional and inflationary memory responses diverge in the spleen and liver, these molecular programs converge in the salivary gland, a site of CMV persistence. Thus, we provide evidence that the dynamics of memory CD8+ T cell responses are distinct between tissues.

Microglia and CD8+ T cell activation precede neuronal loss in a murine model of spastic paraplegia 15

In central nervous system (CNS) diseases characterized by late-onset neurodegeneration, the interplay between innate and adaptive immune responses remains poorly understood. This knowledge gap is exacerbated by the prolonged protracted disease course as it complicates the delineation of brain-resident and infiltrating cells. Here, we conducted comprehensive profiling of innate and adaptive immune cells in a murine model of spastic paraplegia 15 (SPG15), a complicated form of hereditary spastic paraplegia. Using fate-mapping of bone marrow-derived cells, we identified microgliosis accompanied by infiltration and local expansion of T cells in the CNS of Spg15-/- mice. Single-cell analysis revealed an expansion of disease-associated microglia (DAM) and effector CD8+ T cells prior to neuronal loss. Analysis of potential cell-cell communication pathways suggested bidirectional interactions between DAM and effector CD8+ T cells, potentially contributing to disease progression in Spg15-/- mice. In summary, we identified a shift in microglial phenotypes associated with the recruitment and expansion of T cells as a new characteristic of Spg15-driven neuropathology.

Optimization of Immunotherapy Strategies Based on Spatiotemporal Heterogeneity of Tumour-Associated Tissue-Resident Memory T Cells

Tissue-resident memory T cells (TRMs) reside in peripheral tissues and provide rapid immune defence against local infection and tumours. Tumour-associated TRMs share common tissue-resident features and formation mechanisms, representing some unique subsets of tumour-infiltrating lymphocytes (TILs). However, differences in the tumour microenvironment(TME) and tumour evolution stage result in TRMs exhibiting temporal and spatial heterogeneity of phenotype and function not only at different stages, before and after treatment, but also between tumours originating from different tissues, primary and metastatic cancer, and tumour and adjacent normal tissue. The infiltration of TRMs is often associated with immunotherapy response and favourable prognosis; however, due to different definitions, it has been shown that some subtypes of TRMs can also have a negative impact. Therefore, it is crucial to precisely characterise the TRM subpopulations that can influence the therapeutic efficacy and clinical prognosis of various solid tumours. Here, we review the spatiotemporal heterogeneity of tumour-associated TRMs, as well as the differences in their impact on clinical outcomes. We also explore the relationship between TRMs and immune checkpoint blockade (ICB) and TIL therapy, providing insights into potential new targets and strategies for immunotherapy.

Enhancer-driven gene regulatory networks reveal transcription factors governing T cell adaptation and differentiation in the tumor microenvironment

Tumor-infiltrating lymphocytes (TILs) with a tissue-resident memory CD8+ T cell (Trm) phenotype are associated with improved patient outcomes in solid malignancies. To define programs governing the formation of Trm-like TIL, we performed paired single-cell RNA sequencing and single-cell ATAC sequencing of T cell receptor (TCR)-matched CD8+ T cells in models of infection and cancer. Enhancer-driven regulons assembled from multiomic profiling data revealed epigenetic and transcriptional programs regulating the formation of Trm-like TIL in relation to canonical exhausted and memory T cell states. The transcriptional regulator KLF2 repressed the formation of CD69+CD103+ Trm-like TIL and limited anti-tumor activity. Conversely, sustained expression of the transcription factor BATF enhanced formation of CD69+CD103+ TIL, contingent upon downregulation of KLF2. Transforming growth factor β (TGF-β) signaling and CD103 expression were necessary for Trm-like TIL formation, but BATF overexpression was sufficient to drive formation of CD69+CD103+ TIL in TGFBR2-silenced cells. These findings reveal mechanisms of Trm-like TIL differentiation and provide a framework for considering tissue residency in the context of CD8+ T cell heterogeneity in the tumor microenvironment.

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.

Advances in cancer immunotherapy: historical perspectives, current developments, and future directions

Cancer immunotherapy, encompassing both experimental and standard-of-care therapies, has emerged as a promising approach to harnessing the immune system for tumor suppression. Experimental strategies, including novel immunotherapies and preclinical models, are actively being explored, while established treatments, such as immune checkpoint inhibitors (ICIs), are widely implemented in clinical settings. This comprehensive review examines the historical evolution, underlying mechanisms, and diverse strategies of cancer immunotherapy, highlighting both its clinical applications and ongoing preclinical advancements. The review delves into the essential components of anticancer immunity, including dendritic cell activation, T cell priming, and immune surveillance, while addressing the challenges posed by immune evasion mechanisms. Key immunotherapeutic strategies, such as cancer vaccines, oncolytic viruses, adoptive cell transfer, and ICIs, are discussed in detail. Additionally, the role of nanotechnology, cytokines, chemokines, and adjuvants in enhancing the precision and efficacy of immunotherapies were explored. Combination therapies, particularly those integrating immunotherapy with radiotherapy or chemotherapy, exhibit synergistic potential but necessitate careful management to reduce side effects. Emerging factors influencing immunotherapy outcomes, including tumor heterogeneity, gut microbiota composition, and genomic and epigenetic modifications, are also examined. Furthermore, the molecular mechanisms underlying immune evasion and therapeutic resistance are analyzed, with a focus on the contributions of noncoding RNAs and epigenetic alterations, along with innovative intervention strategies. This review emphasizes recent preclinical and clinical advancements, with particular attention to biomarker-driven approaches aimed at optimizing patient prognosis. Challenges such as immunotherapy-related toxicity, limited efficacy in solid tumors, and production constraints are highlighted as critical areas for future research. Advancements in personalized therapies and novel delivery systems are proposed as avenues to enhance treatment effectiveness and accessibility. By incorporating insights from multiple disciplines, this review aims to deepen the understanding and application of cancer immunotherapy, ultimately fostering more effective and widely accessible therapeutic solutions.

Cutaneous T cell immunity

The skin is the primary barrier against environmental insults, safeguarding the body from mechanical, chemical and pathogenic threats. The frequent exposure of the skin to environmental challenges requires an immune response that incorporates a sophisticated combination of defenses. Tissue-resident lymphocytes are pivotal for skin immunity, working in tandem with commensal bacteria to maintain immune surveillance and homeostasis, as well as participating in the pathogenesis of several skin diseases. Indeed, it has been estimated that the human skin harbors nearly twice as many T cells as found in the circulation. Effective treatment of skin diseases and new therapy development require a thorough understanding of the complex interactions among skin tissue, immune cells and the microbiota, which together regulate the skin's immune balance. This Review explores the latest developments and understanding of this critical barrier organ, with a specific focus on the role of skin-resident T cells.

Dysfunctional KLRB1+CD8+ T-cell responses are generated in chronically inflamed systemic sclerosis skin

OBJECTIVES

To analyse the immune mechanisms of diffuse cutaneous systemic sclerosis (dcSSc) skin disease focusing on CD8+ T-cell responses in the affected skin of patients because chronic inflammation, vasculopathy, and extensive cutaneous fibrosis are prominent features of dcSSc skin disease, causing pain and disability in patients, with no effective therapy.

METHODS

Single-cell transcriptomics and epigenomics were applied to well-characterised patient skin samples to identify transcriptomes and key regulators of skin-resident CD8+ T-cell subsets. Multicolor immunofluorescence miscoscopy was used to validate molecular findings. Ex vivo skin explant assays were used to functionally characterise dysfunctional CD8+ T-cell subsets on nonlesional autologous skin.

RESULTS

We identified 2 major developmentally connected CD8+ T-cell subpopulations that were expanded in SSc skin lesions compared with healthy control skin. The first was a heterogeneous subset of effector-memory CD8+KLRB1+IL7R+ cells characterised by increased cytolytic and Tc2/Tc17 effector functions that appear to induce tissue damage and fibrosis in early-stage dcSSc skin lesions. The second, found primarily in patients with late-stage disease, was an exhausted CD8+KLRG1+IL7R- subset that exhibited transcriptional features of long-lived effector cells, likely contributing to chronic inflammation. Significantly, both subsets were also expanded in other benign dermatoses, implicating these cell populations in the pathogenesis of chronic human skin inflammation.

CONCLUSIONS

This study provides new insight into core regulatory programmes modulating skin-resident CD8+ T-cell plasticity and identifies distinct CD8+ T-cell subpopulations that contribute to initiation and chronicity of inflammatory responses in systemic sclerosis skin lesions. These findings reveal prospective molecular targets for new therapeutic strategies against this incurable disease.

Tissue-Resident Memory T Cells in Tumor Immunity and Immunotherapy of Digestive System Tumors

BACKGROUND

Tissue-resident memory T (TRM) cells possess unique abilities to migrate, establish themselves in tissues, and monitor peripheral tissues without circulating. They are crucial in providing long-lasting and local immune protection against surface infections. TRMs demonstrate distinct phenotypic and functional characteristics compared to central memory T (Tcm) cells and effector memory T (Tem) cells.

METHODS

We reviewed a large number of literature to explore the physiological and functional roles of tissue-resident memory T cells, as well as the link between TRM cells and the development and prognosis of digestive tract tumors. We also investigated the association between TRM cells, intestinal flora, and metabolites.

RESULTS

Recent studies have implicated TRMs in the immune response against tumors, making them a potential target for cancer therapy. However, research specifically focused on gastrointestinal tumors is limited.

CONCLUSION

This review aims to compile and assess the most recent data on the role of TRM cells in gastrointestinal tumor immunity. Additionally, it explores recent advancements in immunotherapy and investigates how TRMs may influence intestinal flora and metabolites.

Unravelling the modified T cell receptor through Gen-Next CAR T cell therapy in Glioblastoma: Current status and future challenges

PURPOSE

Despite current technological advancements in the treatment of glioma, immediate alleviation of symptoms can be catered by therapeutic modalities, including surgery, chemotherapy, and combinatorial radiotherapy that exploit aberrations of glioma. Additionally, a small number of target antigens, their heterogeneity, and immune evasion are the potential reasons for developing targeted therapies. This oncologic milestone has catalyzed interest in developing immunotherapies against Glioblastoma to improve overall survival and cure patients with high-grade glioma. The next-gen CAR-T Cell therapy is one of the effective immunotherapeutic strategies in which autologous T cells have been modified to express receptors against GBM and it modulates cytotoxicity.

METHODS

In this review article, we examine preclinical and clinical outcomes, and limitations as well as present cutting-edge techniques to improve the function of CAR-T cell therapy and explore the possibility of combination therapy.

FINDINGS

To date, several CAR T-cell therapies are being evaluated in clinical trials for GBM and other brain malignancies and multiple preclinical studies have demonstrated encouraging outcomes.

IMPLICATIONS

CAR-T cell therapy represents a promising therapeutic paradigm in the treatment of solid tumors but a few limitations include, the blood-brain barrier (BBB), antigen escape, tumor microenvironment (TME), tumor heterogeneity, and its plasticity that suppresses immune responses weakens the ability of this therapy. Additional investigation is required that can accurately identify the targets and reflect the similar architecture of glioblastoma, thus optimizing the efficiency of CAR-T cell therapy; allowing for the selection of patients most likely to benefit from immuno-based treatments.

Multifaceted functions of tissue-resident memory T cells in tumorigenesis and cancer immunotherapy

Tissue-resident memory T (TRM) cells are well reported as a strong protective first line of defense against foreign antigens in non-lymphoid tissues. Moreover, TRM cells have demonstrated critical protective roles in antitumor immunity, contributing to enhanced survival and tumor growth inhibition across various cancer types. However, surprisingly, recent studies suggest that TRM cells can exhibit paradoxical effects, potentially promoting tumor progression under certain conditions and leading to adverse outcomes during antitumor immune responses. Understanding the complexities of TRM cell functions will enable us to harness their potential in advancing cancer immunotherapy more effectively. Therefore, this review comprehensively investigates the dual roles of TRM cells in different tumor contexts, highlighting their protective functions in combating cancers and their unfavorable potential to exacerbate tumor development. Additionally, we explore the implications of TRM cell behaviors for future cancer treatment strategies, emphasizing the need for further research to optimize the therapeutic exploitation of TRM cells while mitigating their deleterious effects.

Tissue-resident immune cells in cervical cancer: emerging roles and therapeutic implications

The favorable prognosis of "hot" tumors is widely acknowledged in oncology. Recently, the concept of tertiary lymphoid structures (TLS) has renewed appreciation for local immune cells within tumor tissues. Tissue-resident immune cells, a newly identified subset of tumor-infiltrating lymphocytes, are emerging as potential key players in tumor infiltration and TLS formation, due to their ability to reside indefinitely within tissues and mount effective responses to local antigens. Cervical cancer (CC), the fourth most common cause of cancer-related mortality among women globally, has experienced comparatively limited progress in delineating its tumor immune microenvironment compared to other malignancies. Notably, the role of tissue-resident immune cells within the CC milieu remains inadequately characterized. This comprehensive review aims to synthesize current knowledge and critically evaluate the putative roles of these cells in CC pathogenesis, providing new insights on the intricate dynamics of the local tumor microenvironment.

Epidermal Resident Memory T Cell Fitness Requires Antigen Encounter in the Skin

CD8 + tissue resident memory T cells (T RM ) develop from effectors that seed peripheral tissues where they persist providing defense against subsequent challenges. T RM persistence requires autocrine TGFβ transactivated by integrins expressed on keratinocytes. T RM precursors that encounter antigen in the epidermis during development outcompete bystander T RM for TGFβ resulting in enhanced persistence. ScRNA-seq analysis of epidermal T RM revealed that local antigen experience in the skin resulted in an enhanced differentiation signature in comparison with bystanders. Upon recall, T RM displayed greater proliferation dictated by affinity of antigen experienced during epidermal development. Finally, local antigen experienced T RM differentially expressed TGFβRIII, which increases avidity of the TGFβRI/II receptor complex for TGFβ. Selective ablation of Tgfbr3 reduced local antigen experienced T RM capacity to persist, rendering them phenotypically like bystander T RM . Thus, antigen driven TCR signaling in the epidermis during T RM differentiation results in a lower TGFβ requirement for persistence and increased proliferative capacity that together enhance epidermal T RM fitness.

Molecular Mechanisms Governing CD8 T Cell Differentiation and Checkpoint Inhibitor Response in Cancer

CD8 T cells play a critical role in antitumor immunity. However, over time, they often become dysfunctional or exhausted and ultimately fail to control tumor growth. To effectively harness CD8 T cells for cancer immunotherapy, a detailed understanding of the mechanisms that govern their differentiation and function is crucial. This review summarizes our current knowledge of the molecular pathways that regulate CD8 T cell heterogeneity and function in chronic infection and cancer and outlines how T cells respond to therapeutic checkpoint blockade. We explore how T cell-intrinsic and -extrinsic factors influence CD8 T cell differentiation, fate choices, and functional states and ultimately dictate their response to therapy. Identifying cells that orchestrate long-term antitumor immunity and understanding the mechanisms that govern their development and persistence are critical steps toward improving cancer immunotherapy.

Predictive Modeling of Immunogenicity to Botulinum Toxin A Treatments for Glabellar Lines

BACKGROUND

Botulinum toxin A (BoNT-A), derived from Clostridium botulinum , is widely used in medical and aesthetic treatments. Its clinical application extends from managing chronic conditions like cervical dystonia and migraine to reducing facial wrinkles. Despite its efficacy, a challenge associated with BoNT-A therapy is immunogenicity, where the immune system produces neutralizing antibodies (NAbs) against BoNT-A, reducing its effectiveness over time. This issue is important for patients requiring repeated treatments. The authors compared BoNT-A products, examining the factors influencing NAb development using advanced machine-learning techniques.

METHODS

The authors analyzed data from randomized controlled trials involving 5 main BoNT-A products. Trials were selected on the basis of detailed reports of immunogenic responses to these treatments, particularly for glabellar lines. Machine-learning models, including logistic regression, random forest classifiers, and Bayesian logistic regression, were used to assess how treatment specifics and BoNT-A product types affect the development of NAbs.

RESULTS

Analysis of 14 studies with 8190 participants revealed that dosage and treatment frequency are key factors influencing the risk of NAb development. Among BoNT-A products, incobotulinumtoxinA shows the lowest, and abobotulinumtoxinA, the highest likelihood of inducing NAbs. The machine-learning and logistic regression findings indicated that treatment planning must consider these variables to minimize immunogenicity.

CONCLUSIONS

The study underscores the importance of understanding BoNT-A immunogenicity in clinical practice. By identifying the main predictors of NAb development and differentiating the immunogenic potential of BoNT-A products, the research provides insights for clinicians in optimizing treatment strategies. It highlights the need for careful treatment customization to reduce immunogenic risks, advocating for further research into the mechanisms of BoNT-A immunogenicity.

Barrier Integrity and Immunity: Exploring the Cutaneous Front Line in Health and Disease

Immune responses are influenced by not only immune cells but also the tissue microenvironment where these cells reside. Recent advancements in understanding the underlying molecular mechanisms and structures of the epidermal tight junctions (TJs) and stratum corneum (SC) have significantly enhanced our knowledge of skin barrier functions. TJs, located in the granular layer of the epidermis, are crucial boundary elements in the differentiation process, particularly in the transition from living cells to dead cells. The SC forms from dead keratinocytes via corneoptosis and features three distinct pH zones critical for barrier function and homeostasis. Additionally, the SC-skin microbiota interactions are crucial for modulating immune responses and protecting against pathogens. In this review, we explore how these components contribute both to healthy and disease states. By targeting the skin barrier in therapeutic strategies, we can enhance its integrity, modulate immune responses, and ultimately improve outcomes for patients with inflammatory skin conditions.

Intestinal tissue-resident memory T cells: Characteristics, functions under physiological and pathological conditions and spatial specificity

BACKGROUND

Tissue-resident memory T (TRM) cells are a distinct subset of memory T cells that persist in non-lymphoid tissues, providing localized and rapid immune responses to infection and malignancy. Unlike circulating memory T cells, TRM cells have unique homing and functional characteristics that are shaped by the tissue microenvironment. In the gut, TRM cells play a pivotal role in maintaining mucosal immunity, exhibiting phenotypic and functional heterogeneity in different intestinal compartments and in response to aging and pathological conditions.

AIM OF REVIEW

This review aims to systematically examine the definition, spatial heterogeneity and functional roles of intestinal TRM (iTRM) cells. It highlights their contributions to physiological immunity, their involvement in pathological processes such as inflammatory bowel disease (IBD) and colorectal cancer (CRC), and their age-related dynamics. The review also explores emerging therapeutic implications of modulating iTRM cells for intestinal health and disease management. KEY SCIENTIFIC CONCEPTS OF REVIEW: iTRM cells are defined by surface markers like CD69 and CD103, transcriptional regulators such as Hobit, Runx3, Blimp-1, as well as cytokine signals including TGF-β, IFN-β, IL-12. They exhibit spatial and functional heterogeneity across intestinal layers (epithelium versus lamina propria) and regions (small intestine versus colon). In IBD, iTRM cells play a dual role, contributing to both inflammation and tissue repair, whereas in CRC, specific subsets of iTRM cells (e.g., CD8+ CD103+ CD39+) are associated with enhanced antitumor immunity. Aging impacts iTRM functionality, with shifts in the CD4+/CD8+ ratio and reduced cytokine production in elderly individuals. Insights into the metabolic, transcriptional, and environmental regulation of iTRM cells provide avenues for targeted therapies in intestinal diseases, cancer immunotherapy, and interventions to delay intestinal aging.

Emerging Therapeutic Innovations for Vitiligo Treatment

Vitiligo is a chronic autoimmune disorder with a multifactorial etiology, typically manifesting as localized or generalized hypopigmentation or depigmentation of the skin and mucous membranes. The pathogenesis of vitiligo is complex and significantly impacts patients' quality of life. Although traditional treatments such as hormone therapy, topical medications, and laser therapy can help control the disease to some extent, their outcomes remain unsatisfactory. Therefore, ongoing research is crucial to explore and develop novel treatment strategies while assessing their efficacy and safety. This review aims to classify and summarize various new candidate drugs for vitiligo currently undergoing clinical trials, providing a reference for clinical practice. Recent advancements in the understanding of the pathogenesis of vitiligo have facilitated the development of potential treatment strategies, such as Janus kinase inhibitors, cytokine blockers, and agents targeting tissue-resident memory or regulatory T cells. These emerging therapies offer hope to patients with vitiligo, though further investigation is needed to confirm their safety, efficacy, and optimal treatment regimens.

Collaboration between interleukin-7 and -15 enables adaptation of tissue-resident and circulating memory CD8+ T cells to cytokine deficiency

Interleukin-7 (IL-7) is considered a critical regulator of memory CD8+ T cell homeostasis. However, this is primarily based on circulating memory populations, and the cell-intrinsic requirement for IL-7 signaling during memory homeostasis has not been directly tested. Here, we addressed the role for IL-7Rα in circulating and resident memory CD8+ T cells (Trm) after their establishment. We found that inducible Il7ra deletion had only a modest effect on persistence of circulating memory and Trm subsets, causing reduced basal proliferation. Loss of IL-15 signaling imposed heightened IL-7Rα dependence on memory CD8+ T cells, including Trm cells described as IL-15 independent. In the absence of IL-15 signaling, IL-7Rα was elevated, and loss of IL-7Rα signaling reduced IL-15-elicited proliferation, suggesting crosstalk between these pathways in memory CD8+ T cells. Thus, across subsets and tissues, IL-7 and IL-15 act in concert to support memory CD8+ T cells, conferring resilience to altered availability of either cytokine.

Angel and devil: the protective immunity and pathogenic inflammation of tissue resident memory T cells in ulcerative colitis

Ulcerative colitis (UC) is an incurable autoimmune disease. Patients with UC endure the burden of recurrent flare-ups and face a substantial economic burden due to long-term medication. The complex etiology and unclear pathogenesis pose a significant challenge to the development of effective and curative treatments. Recent research indicates that local memory at the site of inflammatory intestinal mucosa in UC is closely associated with the persistent presence of tissue-resident memory T (TRM) cells. TRM cells, a subset of memory T cells, exhibit long-lived, low-migration characteristics. These cells reside in tissues, where they provide immediate immune protection while also contributing to chronic, localized inflammation. The presence of TRM cells in the inflamed intestinal mucosa of UC patients is a crucial factor in the recurrence of the disease. However, the process involved in the formation and differentiation of TRM cells within the intestinal mucosa remains poorly understood. Various surface markers, transcriptional networks, and signaling pathways regulate the formation and maintenance of TRM cells in the intestine. To further understand the role of TRM cells in UC pathogenesis, we have summarized the latest findings to pave the way for the development of future targeted therapies.

Autocrine TGF-β1 drives tissue-specific differentiation and function of resident NK cells

Group 1 innate lymphoid cells (ILCs) encompass NK cells and ILC1s, which have non-redundant roles in host protection against pathogens and cancer. Despite their circulating nature, NK cells can establish residency in selected tissues during ontogeny, forming a distinct functional subset. The mechanisms that initiate, maintain, and regulate the conversion of NK cells into tissue-resident NK (trNK) cells are currently not well understood. Here, we identify autocrine transforming growth factor-β (TGF-β) as a cell-autonomous driver for NK cell tissue residency across multiple glandular tissues during development. Cell-intrinsic production of TGF-β was continuously required for the maintenance of trNK cells and synergized with Hobit to enhance cytotoxic function. Whereas autocrine TGF-β was redundant in tumors, our study revealed that NK cell-derived TGF-β allowed the expansion of cytotoxic trNK cells during local infection with murine cytomegalovirus (MCMV) and contributed to viral control in the salivary gland. Collectively, our findings reveal tissue-specific regulation of trNK cell differentiation and function by autocrine TGF-β1, which is relevant for antiviral immunity.

How oxygenation shapes immune responses: emerging roles for physioxia and pathological hypoxia

Most eukaryotes require oxygen for their survival and, with increasing multicellular complexity, oxygen availability and delivery rates vary across the tissues of complex organisms. In humans, healthy tissues have markedly different oxygen gradients, ranging from the hypoxic environment of the bone marrow (where our haematopoietic stem cells reside) to the lungs and their alveoli, which are among the most oxygenated areas of the body. Immune cells are therefore required to adapt to varying oxygen availability as they move from the bone marrow to peripheral organs to mediate their effector functions. These changing oxygen gradients are exaggerated during inflammation, where oxygenation is often depleted owing to alterations in tissue perfusion and increased cellular activity. As such, it is important to consider the effects of oxygenation on shaping the immune response during tissue homeostasis and disease conditions. In this Review, we address the relevance of both physiological oxygenation (physioxia) and disease-associated hypoxia (where cellular oxygen demand outstrips supply) for immune cell functions, discussing the relevance of hypoxia for immune responses in the settings of tissue homeostasis, inflammation, infection, cancer and disease immunotherapy.

Tissue-resident memory CD8 T cell diversity is spatiotemporally imprinted

Tissue-resident memory CD8 T (TRM) cells provide protection from infection at barrier sites. In the small intestine, TRM cells are found in at least two distinct subpopulations: one with higher expression of effector molecules and another with greater memory potential1. However, the origins of this diversity remain unknown. Here we proposed that distinct tissue niches drive the phenotypic heterogeneity of TRM cells. To test this, we leveraged spatial transcriptomics of human samples, a mouse model of acute systemic viral infection and a newly established strategy for pooled optically encoded gene perturbations to profile the locations, interactions and transcriptomes of pathogen-specific TRM cell differentiation at single-transcript resolution. We developed computational approaches to capture cellular locations along three anatomical axes of the small intestine and to visualize the spatiotemporal distribution of cell types and gene expression. Our study reveals that the regionalized signalling of the intestinal architecture supports two distinct TRM cell states: differentiated TRM cells and progenitor-like TRM cells, located in the upper villus and lower villus, respectively. This diversity is mediated by distinct ligand-receptor activities, cytokine gradients and specialized cellular contacts. Blocking TGFβ or CXCL9 and CXCL10 sensing by antigen-specific CD8 T cells revealed a model consistent with anatomically delineated, early fate specification. Ultimately, our framework for the study of tissue immune networks reveals that T cell location and functional state are fundamentally intertwined.

Immune-Epithelial Cell Interactions during Epidermal Regeneration, Repair, and Inflammatory Diseases

The multiple layers of the skin cover and protect our entire body. Among the skin layers, the epidermis is in direct contact with the outer environment and serves as the first line of defense. The epidermis functions as a physical and immunological barrier. To maintain barrier function, the epidermis continually regenerates and repairs itself when injured. Interactions between tissue-resident immune cells and epithelial cells are essential to sustain epidermal regeneration and repair. In this review, we will dissect the crosstalk between epithelial cells and specific immune cell populations located in the epidermis during homeostasis and wound repair. In addition, we will analyze the contribution of dysregulated immune-epithelial interactions in chronic inflammatory diseases.

Tissue-resident memory T cells in urinary tract diseases

Tissue-resident memory T (TRM) cells are a specialized subset of memory T cells that permanently reside in non-lymphoid tissues, providing localized and long-lasting immune protection. In the urinary tract, TRM cells play critical roles in defending against infections, mediating tumor immunity, and influencing the pathogenesis of chronic inflammatory diseases. Their therapeutic potential is immense, with promising avenues for vaccine development, enhanced cancer immunotherapy, and targeted treatments for chronic inflammation. However, challenges remain in harnessing their protective roles while minimizing their pathological effects, particularly in immunosuppressive or inflammatory microenvironments. This review explores the diverse roles of TRM cells in urinary tract diseases, including infections, cancer, and chronic inflammation, and discusses therapeutic strategies and future directions for leveraging TRM cells to improve clinical outcomes. By advancing our understanding of TRM cell biology, we can develop innovative interventions that balance their immune-protective and regulatory functions.

The cancer-associated fibroblasts interact with malignant T cells in mycosis fungoides and promote the disease progression

Background

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of T-cell lymphomas characterized with the presence of clonal malignant T cells. Mycosis fungoides (MF) is the most common type of CTCL. However, the pathogenesis of MF and the role of the tumor microenvironment (TME) remain unclear.

Methods

We performed single-cell RNA sequencing on tumor and adjacent normal tissues and peripheral blood mononuclear cell (PBMC) from patients with advanced MF and healthy control (HC). We compared skin lesions in different stages within the same patient to overcome inter-individual variability.

Results

The malignant clones displayed dual phenotypes characterized with tissue-resident memory T cells (TRMs) and central memory T cells (TCMs). We supposed that the tumor cells transformed from TRM-dominant phenotype to TCM-dominant phenotype during MF progressed from early-stage to advanced-stage. The cancer-associated fibroblasts (CAFs) showed active role in TME. The occurrence of inflammatory CAFs (iCAFs) may represent the advanced-stage MF. There may be mutual positive feedback of the crosstalk between tumor cells and CAFs during the MF development. Tumor cells promote CAF generation, and the CAFs, in turn, improve the invasiveness and metastasis of the malignant T cells through the IL-6/JAK2/STAT3/SOX4 or IL-6/HIF-1α/SOX4 pathway. SOX4 may be a critical regulatory gene of this positive feedback loop. Target SOX4 may disrupt the interactions between tumor cells and CAFs.

Conclusion

Our study revealed the origin and evolution trajectory of MF and uncovered the intercellular interactions between malignant T cells and CAFs, providing new insights into the novel treatment targets of MF.

Herpes stromal keratitis erodes the establishment of tissue-resident memory T cell pool in HSV-1 infected corneas

The recurrent herpes simplex virus-1 (HSV-1) infection of the cornea can cause the development of herpes stromal keratitis (HSK). This chronic immunoinflammatory condition is a major cause of infection-induced vision loss. The previous episodes of HSK increase the risk of future recurrences in the same cornea. However, not all HSV-1 infected corneas that shed infectious virus at the ocular surface develop HSK, suggesting that corneal HSV-1 infection may cause an establishment of protective immunity in HSV-1 infected corneas. However, upon recurrent corneal HSV-1 infection, the established protective immunity can get compromised, resulting in the development of HSK. In this study, we compared the quantity and quality of tissue-resident memory T (TRM) cells in HSV-1 infected corneas that did or did not develop HSK. Our results showed the predominance of TRM cell in the epithelium than in stroma of HSV-1 infected corneas. Furthermore, HSV-1 infected non-HSK corneas exhibited more CD4 and CD8 TRM cells than HSK corneas. The TRM cells in non-HSK than in HSK corneas were more effective in clearing the infectious virus upon secondary corneal HSV-1 infection. Our results demonstrate the differential quantity and quality of TRM cells in HSV-1 infected corneas that did or did not develop HSK.

Organ-specific microenvironments drive divergent T cell evolution in acute graft-versus-host disease

Tissue-specific T cell immune responses play a critical role in maintaining organ health but can also drive immune pathology during both autoimmunity and alloimmunity. The mechanisms controlling intratissue T cell programming remain unclear. Here, we leveraged a nonhuman primate model of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation to probe the biological underpinnings of tissue-specific alloimmune disease using a comprehensive systems immunology approach including multiparameter flow cytometry, population-based transcriptional profiling, and multiplexed single-cell RNA sequencing and TCR sequencing. Transcriptional profiling revealed substantial biological differences between T cells infiltrating the lung and liver during aGVHD. These included enrichment for transcriptional pathways controlling extracellular matrix remodeling and chemotaxis in the lung and enrichment for transcriptional pathways linked to nucleic acid metabolism and proliferation in the liver. Single-cell RNA sequencing and TCR sequencing substantiated divergent organ-specific transcriptional programing of tissue-infiltrating T cells, which was linked to clonal expansion, with expanded clones progressively enriched for C-X3-C motif chemokine receptor 1 (CX3CR1)-expressing CD8 effector T cells in the lung and eomesodermin (EOMES)-expressing CD8 effector-memory T cells in the liver. This divergent evolution of T cells was maintained even for T cells sharing the same TCRs, indicating its independence from antigen specificity. Together, these results provide insights into the role that tissue microenvironment-derived signals play in local T cell transcriptional programming during alloimmune-mediated clonal expansion and suggest potential opportunities to develop tissue-specific therapeutics to curtail pathogenic immunity after transplant.

Engineering resilient CAR T cells for immunosuppressive environment

Chimeric antigen receptor (CAR) T cell therapy has revolutionized cancer treatment and is now being explored for other diseases, such as autoimmune disorders. While the tumor microenvironment (TME) in cancer is often immunosuppressive, in autoimmune diseases, the environment is typically inflammatory. Both environments can negatively impact CAR T cell survival: the former through direct suppression, hypoxia, and nutrient deprivation, and the latter through chronic T cell receptor (TCR) engagement, risking exhaustion. Mechanisms of resistance include T cell exhaustion, dysfunction, and the impact of the TME. Chronic antigenic stimulation leads to CAR T cell exhaustion. CAR construct design, including co-stimulatory domains, hinge, transmembrane regions, promoters, the affinity of the binder site, and on/off rate plays a crucial role in modulating CAR T cell function and resistance. This review discusses the impact of the in vitro development of CAR T cells, albeit in relation to the TME, on therapeutic outcomes. The use of alternative cell sources, multi-antigen targeting, and reengineering the TME, are discussed. The review emphasizes the need for continued innovation in CAR T cell design and manufacturing to optimize therapeutic efficacy and durability, especially in the face of varying environmental challenges.

CD226 identifies effector CD8+ T cells during tuberculosis and costimulates recognition of Mycobacterium tuberculosis-infected macrophages

CD8+ T cells defend against Mycobacterium tuberculosis (Mtb) infection but variably recognize Mtb-infected macrophages. To define how the diversity of lung parenchymal CD8+ T cells changes during chronic infection, cells from C57BL/6J mice infected for 6- and 41-weeks were analyzed by scRNA-seq. We identified an effector lineage, including a cluster that expresses high levels of cytotoxic effectors and cytokines, and dysfunctional lineage that transcriptionally resembles exhausted T cells. The most significant differentially expressed gene between two distinct CD8+ T cell lineages is CD226. Mtb-infected IFNγ-eYFP reporter mice revealed IFNγ production is enriched in CD226+CD8+ T cells, confirming these as functional T cells in vivo. Purified CD226+ but not CD226- CD8+ T cells recognize Mtb-infected macrophages, and CD226 blockade inhibits IFNγ and granzyme B production. Thus, CD226 costimulation is required for efficient CD8+ T cell recognition of Mtb-infected macrophages, and its expression identifies CD8+ T cells that recognize Mtb-infected macrophages.

Tissue-resident immune cells: from defining characteristics to roles in diseases

Tissue-resident immune cells (TRICs) are a highly heterogeneous and plastic subpopulation of immune cells that reside in lymphoid or peripheral tissues without recirculation. These cells are endowed with notably distinct capabilities, setting them apart from their circulating leukocyte counterparts. Many studies demonstrate their complex roles in both health and disease, involving the regulation of homeostasis, protection, and destruction. The advancement of tissue-resolution technologies, such as single-cell sequencing and spatiotemporal omics, provides deeper insights into the cell morphology, characteristic markers, and dynamic transcriptional profiles of TRICs. Currently, the reported TRIC population includes tissue-resident T cells, tissue-resident memory B (BRM) cells, tissue-resident innate lymphocytes, tissue-resident macrophages, tissue-resident neutrophils (TRNs), and tissue-resident mast cells, but unignorably the existence of TRNs is controversial. Previous studies focus on one of them in specific tissues or diseases, however, the origins, developmental trajectories, and intercellular cross-talks of every TRIC type are not fully summarized. In addition, a systemic overview of TRICs in disease progression and the development of parallel therapeutic strategies is lacking. Here, we describe the development and function characteristics of all TRIC types and their major roles in health and diseases. We shed light on how to harness TRICs to offer new therapeutic targets and present burning questions in this field.

Divergent Clinical and Immunologic Outcomes Based on STK11 Co-mutation Status in Resectable KRAS-Mutant Lung Cancers Following Neoadjuvant Immune Checkpoint Blockade

PURPOSE

Co-mutations of the Kirsten rat sarcoma virus (KRAS) and serine/threonine kinase 11 (STK11) genes in advanced non-small cell lung cancer (NSCLC) are associated with immune checkpoint blockade (ICB) resistance. Although neoadjuvant chemoimmunotherapy is now a standard-of-care treatment for resectable NSCLC, the clinical and immunologic impacts of KRAS and STK11 co-mutations in this setting are unknown.

EXPERIMENTAL DESIGN

We evaluated and compared recurrence-free survival of resectable KRAS-mutated NSCLC tumors, with or without co-occurring STK11 mutations, treated with neoadjuvant ICB. Single-cell transcriptomics was performed on tumor-infiltrating T cells from seven KRASmut/STK11wt tumors and six KRAS and STK11 co-mutated (KRASmut/STK11mut) tumors.

RESULTS

Relative to KRASmut/STK11wt tumors, KRASmut/STK11mut exhibited significantly higher recurrence risk. Single-cell transcriptomics showed enhanced oxidative phosphorylation with evidence of decreased prostaglandin E2 signaling and increased IL-2 signaling in CD8+ tumor-infiltrating lymphocytes (TIL) from KRASmut/STK11mut tumors, a finding that was mirrored in KRASwt tumors that relapsed. TILs from KRASmut/STK11mut tumors expressed high levels of molecules associated with tumor residence, including CD39 and ZNF683 (HOBIT).

CONCLUSIONS

These divergent T-cell transcriptional fates suggest that T-cell maintenance and residence may be detrimental to antitumor immunity in the context of neoadjuvant ICB for resectable NSCLC, regardless of KRAS mutation status. Our work provides a basis for future investigations into the mechanisms underpinning prostaglandin E2 signaling and IL-2 signaling as they relate to T-cell immunity to cancer and to divergent clinical outcomes in KRASmut/STK11mut NSCLC treated with neoadjuvant ICB.

Deep profiling deconstructs features associated with memory CD8+ T cell tissue residence

Tissue-resident memory CD8+ T (Trm) cells control infections and cancer and are defined by their lack of recirculation. Because migration is difficult to assess, residence is usually inferred by putative residence-defining phenotypic and gene signature proxies. We assessed the validity and universality of residence proxies by integrating mouse parabiosis, multi-organ sampling, intravascular staining, acute and chronic infection models, dirty mice, and single-cell multi-omics. We report that memory T cells integrate a constellation of inputs-location, stimulation history, antigen persistence, and environment-resulting in myriad differentiation states. Thus, current Trm-defining methodologies have implicit limitations, and a universal residence-specific signature may not exist. However, we define genes and phenotypes that more robustly correlate with tissue residence across the broad range of conditions that we tested. This study reveals broad adaptability of T cells to diverse stimulatory and environmental inputs and provides practical recommendations for evaluating Trm cells.

CD49a Targeting Enhances NK Cell Function and Antitumor Immunity

Approximately 70% of patients receiving immune checkpoint blockade therapies develop treatment resistance. Thus, there is a need for the identification of additional immunotherapeutic targets. CD49a is a membrane protein expressed on NK cells and T cells. In this study, we found that CD49a was highly expressed on the surface of tumor-infiltrating NK cells in various mouse tumor models and that CD49a+ tumor-infiltrating NK cells were more exhausted than CD49a- tumor-infiltrating NK cells. Furthermore, CD49a or NK-specific CD49a deficiency slowed tumor growth and prolonged survival in several mouse tumor models, primarily through the essential role played by NK cells in antitumor activities. Blockade of CD49a using an mAb suppressed tumor development in mice, and combination treatment with anti-PD-L1 further enhanced antitumor efficacy. Our research reveals CD49a on NK cells as an immunotherapeutic target and highlights the potential clinical applications of CD49a-targeted therapies.

Tissue-resident memory T cells in diseases and therapeutic strategies

Tissue-resident memory T (TRM) cells are crucial components of the immune system that provide rapid, localized responses to recurrent pathogens at mucosal and epithelial barriers. Unlike circulating memory T cells, TRM cells are located within peripheral tissues, and they play vital roles in antiviral, antibacterial, and antitumor immunity. Their unique retention and activation mechanisms, including interactions with local epithelial cells and the expression of adhesion molecules, enable their persistence and immediate functionality in diverse tissues. Recent advances have revealed their important roles in chronic inflammation, autoimmunity, and cancer, illuminating both their protective and their pathogenic potential. This review synthesizes current knowledge on TRM cells' molecular signatures, maintenance pathways, and functional dynamics across different tissues. We also explore the interactions of TRM cells with other immune cells, such as B cells, macrophages, and dendritic cells, highlighting the complex network that underpins the efficacy of TRM cells in immune surveillance and response. Understanding the nuanced regulation of TRM cells is essential for developing targeted therapeutic strategies, including vaccines and immunotherapies, to enhance their protective roles while mitigating adverse effects. Insights into TRM cells' biology hold promise for innovative treatments for infectious diseases, cancer, and autoimmune conditions.

Induction of tissue resident memory T cells by measles vaccine vector

Measles live attenuated vaccine (MV) induces strong humoral and cellular systemic memory responses allowing the successful control of measles since decades. MV has also been adapted into a promising vaccine platform with several vaccine candidates in clinical development. To understand and document the tissue-scaled memory response induced by MV, we explored the specific induction and persistence of resident memory T cells (Trm) in the lungs and the liver, two critical targeted tissues for vaccine development against several diseases. Trm are a subset of non-circulating highly specialized T cells. They are found at multiple barrier and mucosal sites, conveniently positioned to rapidly react against pathogens. The induction of Trm in different tissues is therefore critical for vaccine development. We demonstrated in mice the rapid generation of MV-specific and vectorized antigen-specific Trm in the liver and the lungs after a single dose, whatever the route of immunization. The intranasal route induced more Trm in the lungs than other routes, confirming the potential of intranasal vaccine administration of replicative viral vectors to generate a strong pulmonary immune response. MV-specific Trm cells were functionally active, with CD8+ Trm secreting granzyme B upon in vitro restimulation and CD4+ Trm cells secreting IFN-γ and TNF-α. We confirmed in human lymphocytes this tissue tropism by showing an overexpression of homing receptors directing them to epithelial and inflamed tissues. Vaccination strategies able to induce Trm cells at key sites represent a promising field to improve current vaccines, prioritize vaccine platforms and design future vaccines with enhanced protective efficacy.

BACH2-driven tissue resident memory programs promote HIV-1 persistence

Transcription repressor BACH2 redirects short-lived terminally differentiated effector into long-lived memory cells. We postulate that BACH2-mediated long-lived memory programs promote HIV-1 persistence in gut CD4+ T cells. We coupled single-cell DOGMA-seq and TREK-seq to capture chromatin accessibility, transcriptome, surface proteins, T cell receptor, HIV-1 DNA and HIV-1 RNA in 100,744 gut T cells from ten aviremic HIV-1+ individuals and five HIV-1- donors. BACH2 was the leading transcription factor that shaped gut tissue resident memory T cells (TRMs) into long-lived memory with restrained interferon-induced effector function. We found that HIV-1-infected cells were enriched in TRMs (80.8%). HIV-1-infected cells had increased BACH2 transcription factor accessibility, TRM (CD49a, CD69, CD103) and survival (IL7R) gene expression, and Th17 polarization (RORC, CCR6). In vitro gut CD4+ T cell infection revealed preferential infection and persistence of HIV-1 in CCR6+ TRMs. Overall, we found BACH2-driven TRM program promotes HIV-1 persistence and BACH2 as a new therapeutic target.

Tissue-Resident T Cells in Clinical Response and Immune-Related Adverse Events of Immune Checkpoint Blockade

T-cell surveillance of tissues is spatially organized: circulating memory T cells perform surveillance of secondary lymphoid organs, whereas tissue-resident memory T cells act as sentinels in barrier tissues. In the context of infection, tissue-resident memory T cells survive long term in barrier tissues and are poised to respond to re-encounter of infectious agents. The activity of such tissue-resident T cells is regulated by the PD-1 and cytotoxic T-lymphocyte-associated protein 4 inhibitory receptors targeted by cancer immunotherapies. This review investigates the hypothesis that T cells with a tissue residency program play an important role in both protective antitumor immunity and immune-related adverse events (irAE) of immune checkpoint blockade (ICB). A series of translational studies have demonstrated that a higher density of tissue-resident T cells within tumors is associated with favorable survival outcomes in a diverse range of cancer types. Tissue-resident T cells have also been implicated in clinical response to ICB, and dynamic tracking of T-cell populations in pre- and on-treatment tumor samples demonstrated that T cells with a tissue residency program responded early to ICB. Investigation of colitis and dermatitis as examples of irAEs demonstrated that tissue-resident memory T cells were reactivated at these epithelial sites, resulting in a highly cytotoxic state and secretion of inflammatory cytokines IFNγ and TNFα. It will therefore be important to consider how a tissue residency program can be enhanced to promote T-cell-mediated tumor immunity while preventing the development of irAEs.

IL-33 Increases the Magnitude of the Tissue-Resident Memory T Cell Response in Intestinal Tissues during Local Infection

IL-33 plays an important role in the early programming of CD8 T cells; however, its contribution to the differentiation of tissue-resident memory T cells in vivo remains poorly defined. After infection of mice with Yersinia pseudotuberculosis, IL-33 expression was increased in the intestinal tissue, and this coincided with the expression of ST2 on T cells infiltrating the intestinal epithelium and lamina propria. Blocking IL-33 signaling after T cell infiltration of the intestinal tissue did not significantly impact the number or phenotype of tissue-resident memory T cells generated. However, overexpression of ST2 on T cells was able to increase expression of TCF1 and T cell number in the intestine compared with the lymphoid organs during infection. We also observed that enhanced accumulation and maintenance of ST2-overexpressing cells in the intestine postinfection were resolved. This points to a role for IL-33 in increasing the number of T cells that commit to intestinal tissue residency in vivo.

Ex vivo expansion and hydrogel-mediated in vivo delivery of tissue-resident memory T cells for immunotherapy

Tissue-resident memory T (TRM) cells preferentially reside in peripheral tissues, serving as key players in tumor immunity and immunotherapy. The lack of effective approaches for expanding TRM cells and delivering these cells in vivo hinders the exploration of TRM cell-mediated cancer immunotherapy. Here, we report a nanoparticle artificial antigen-presenting cell (nano-aAPC) ex vivo expansion approach and an in vivo delivery system for TRM cells. Using the nano-aAPC platform, we expanded functional antigen-specific murine and human TRM-like CD8+ T cells ex vivo. We also developed an injectable macroporous hyaluronic acid (HA) hydrogel to deliver TRM-like cells. TRM-like cells delivered in the optimized HA hydrogel trigger robust local and systemic antitumor immunity and show synergistic effects with anti-PD-1 treatment. Our findings suggest that nano-aAPC-induced TRM-like cells, coupled with a hydrogel delivery system, offer an efficient way to advance the understanding of TRM cell-mediated cancer therapy.

Differential predictive value of resident memory CD8+T cell subpopulations in patients with non-small-cell lung cancer treated by immunotherapy

BACKGROUND

A high density of resident memory T cells (TRM) in tumors correlates with improved clinical outcomes in immunotherapy-treated patients. In most clinical studies, TRM are defined by the CD103 marker. However, it is clearly established that not all TRM express CD103, but can be defined by other markers (CD49a, CD69, etc). The frequency of these subpopulations of TRM expressing or not CD103 varies according to the location of the cancer. Little is known about their functionality and their predictive impact on response to immunotherapy. In preclinical models, only some subpopulations of TRM are associated with cancer vaccine efficacy.

METHODS

Multiparametric cytometry analyses were used to demonstrate the presence of TRM subpopulations in the lung in mice after vaccination and in fresh ex vivo human non-small cell lung cancer (NSCLC). An analysis of the T-cell repertoire of these TRM was conducted to search for their relationships. Multiplex immunofluorescence techniques were used to quantify intratumor infiltration of TRM subpopulations in two cohorts of patients with NSCLC. The impact on the clinical outcome of the TRM tumor infiltration was also investigated.

RESULTS

We identified two main TRM subpopulations in tumor-infiltrating lymphocytes derived from patients with NSCLC: one co-expressing CD103 and CD49a (double positive (DP)), and the other expressing only CD49a (simple positive (SP)); both exhibiting additional TRM surface markers like CD69. Despite higher expression of inhibitory receptors, DP TRM exhibited greater functionality compared with SP TRM. Analysis of T-cell receptor (TCR) repertoire and expression of the stemness marker TCF1 revealed shared TCRs between populations, with the SP subset appearing more progenitor-like phenotype. In the training cohort, PD-L1 (Programmed Death-Ligand 1) and TCF1+CD8+T cells predict response to anti-PD-1. In patient with NSCLC validation cohorts, only DP TRM predicted PD-1 blockade response. Multivariate analysis, including various biomarkers associated with responses to anti-PD-(L)1, such as total CD8, TCF1+CD8+T cells, and PD-L1, showed that only intratumoral infiltration by DP TRM remained significant.

CONCLUSIONS

This study highlights the non-equivalence of TRM subpopulations. The population of TRM co-expressing CD103 and CD49a appears to be the most functional and has the most significant capacity for predicting response to immunotherapy in multivariate analysis in patients with NSCLC.

Post-translational modification in the pathogenesis of vitiligo

Vitiligo is a chronic dermatological condition marked by the loss of skin pigmentation. Its complex etiology involves multiple factors and has not been completely elucidated. Protein post-translational modification pathways have been proven to play a significant role in inflammatory skin diseases, yet research in the context of vitiligo remains limited. This review focuses on the role of post-translational modifications in vitiligo pathogenesis, especially their impact on cellular signaling pathways related to immune response and melanocyte survival. Current therapeutic strategies targeting these pathways are discussed, emphasizing the potential for novel treatments in vitiligo management.

Tissue-resident memory cells in antitumoral immunity and cancer immunotherapy

As cancer immunotherapy evolves, tissue-resident memory (TRM) cells remain key contributors to the antitumoral immune response due to their ability to mediate local tumor control, high expression of immune checkpoints, potential to respond to immunotherapy, and location across tissue sites where distal tumor metastases occur. This review synthesizes recent findings on the biology of TRM cells, their role in cancer, and their interactions with the tumor microenvironment. We also identify several critical research gaps, such as how mechanistic interrogation of TRM cell function is required for integration into therapeutics, proposing a focused research agenda to better exploit their potential.

Please don't go: retinoic acid 'retains' tissue-specific memory

Tissue-resident memory (TRM) T cells not only control infection and cancer, but also contribute to inflammatory disease. In a recent study, Obers et al. demonstrate that retinoic acid (RA) and TGF-β direct TRM residency in mice, with RA uniquely retaining cells in the intestine by limiting migration. This discovery highlights the potential for harnessing local residency cues to enhance tissue-specific TRM responses.

Retention of ES cell-derived 129S genome drives NLRP1 hypersensitivity and transcriptional deregulation in Nlrp3tm1Flv mice

Immune response genes are highly polymorphic in humans and mice, with heterogeneity amongst loci driving strain-specific host defence responses. The inadvertent retention of polymorphic loci can introduce confounding phenotypes, leading to erroneous conclusions, and impeding scientific advancement. In this study, we employ a combination of RNAseq and variant calling analyses to identify a substantial region of 129S genome, including the highly polymorphic Nlrp1 locus, proximal to Nlrp3, in one of the most commonly used mouse models of NLRP3 deficiency (Nlrp3tm1Flv). We show that the presence of the Nlrp1129S locus leads to an increase in NLRP1B protein expression, and a sensitising of Nlrp3tm1Flv macrophages to NLRP1 inflammasome activation, independent of NLRP3 deficiency. Retention of 129S genome further leads to protein sequence differences and altered gene regulation across multiple cell types, including of the key tissue-resident macrophage marker, TIM4. Using alternative models of NLRP3 deficiency, including a previously undescribed conditional Nlrp3 allele enabling precise temporal and cell-type specific control over Nlrp3 deletion, we further show that NLRP3 contributes to Talabostat-driven IL-1β release. Our study also establishes a generic framework to identify functionally relevant SNPs and assess genomic contamination in transgenic mice using RNAseq data. This allows for unambiguous attribution of phenotypes to the target gene and advances the precision and reliability of research in the field of host defence responses.

Respiratory delivered vaccines: Current status and perspectives in rational formulation design

The respiratory tract is susceptible to various infections and can be affected by many serious diseases. Vaccination is one of the most promising ways that prevent infectious diseases and treatment of some diseases such as malignancy. Direct delivery of vaccines to the respiratory tract could mimic the natural process of infection and shorten the delivery path, therefore unique mucosal immunity at the first line might be induced and the efficiency of delivery can be high. Despite considerable attempts at the development of respiratory vaccines, the rational formulation design still warrants attention, i.e., how the formulation composition, particle properties, formulation type (liquid or solid), and devices would influence the immune outcome. This article reviews the recent advances in the formulation design and development of respiratory vaccines. The focus is on the state of the art of delivering antigenic compounds through the respiratory tract, overcoming the pulmonary bio-barriers, enhancing delivery efficiencies of respiratory vaccines as well as maintaining the stability of vaccines during storage and use. The choice of devices and the influence of deposition sites on vaccine efficiencies were also reviewed.

Immunomodulatory potential of primary cilia in the skin

Primary cilia (PC) are essential signaling hubs for proper epithelial formation and the maintenance of skin homeostasis. Found on most cells in the human body, including skin cells, PC facilitate signal transduction that allows ciliated cells to interact with the immune system via multiple pathways, helping to maintain immune system homeostasis. PC can be altered by various microenvironmental stimuli to develop corresponding regulatory functions. Both PC and ciliary signaling pathways have been shown to be involved in the immune processes of various skin lesions. However, the mechanisms by which PC regulate cellular functions and maintain immune homeostasis in tissues are highly complex, and our understanding of them in the skin remains limited. In this paper, we discuss key ciliary signaling pathways and ciliated cells in the skin, with a focus on their immunomodulatory functions. We have compiled evidence from various cells, tissues and disease models to help explore the potential immunomodulatory effects of PC in the skin and their molecular mechanisms.

Mucosal Inflammatory Memory in Chronic Rhinosinusitis

Recent advancements in medical management, endoscopic sinus surgery, and biologics have significantly improved outcomes for patients with chronic rhinosinusitis (CRS). However, long-term recurrence is frequently observed following endoscopic sinus surgery, with symptoms worsening after biologics are discontinued. Consequently, refractory or recurrent CRS remains a significant challenge, causing a substantial healthcare burden. In this review, we provide current insights into mucosal inflammatory memory, a potential mechanism leading to CRS recurrence. Given that both immune and non-immune cells in the sinonasal mucosa play critical roles in the pathophysiology of CRS, a deeper understanding of the mechanisms underlying mucosal inflammatory memory in various cellular components of sinonasal tissue could aid in the management of refractory CRS. We describe and discuss the latest knowledge regarding the novel concept of inflammatory memory, including both adaptive immune memory and trained immunity. Additionally, we summarize the pathogenic memory features of the sinonasal mucosa cellular components in the context of CRS.

Dual CD47 and PD-L1 blockade elicits anti-tumor immunity by intratumoral CD8+ T cells

Objectives

Bispecific antibodies targeting CD47 and PD-L1 (CD47 × PD-L1 BisAb) demonstrate efficacy against a range of solid cancers. While dual blockade negates anti-CD47-mediated toxicity, the effect of combined innate and adaptive immune activation on protective tumor-resident CD8+ T cells has yet to be fully elucidated.

Methods

CD8+ T cell populations were tracked upon CD47 × PD-L1 BisAb treatment in an orthotopic model of murine breast cancer where anti-tumor immunity is mediated by CD8+ T cells. Immune responses were also compared with anti-PD-L1 monotherapy to assess the advantage of dual checkpoint targeting.

Results

We found that CD47 × PD-L1 BisAb treatment augmented CD8+ T cell responses in tumors, which resulted in enhanced tumor control. Compared with anti-PD-L1 treatment, dual CD47 and PD-L1 blockade promoted greater numbers of antigen-specific tumor-resident CD8+ T cells that exhibited increased cytokine production.

Conclusions

Engagement of innate and adaptive immune checkpoint molecules via CD47 × PD-L1 BisAb treatment resulted in robust CD8+ T cell responses, including the induction of tumor-resident CD8+ T cells that exhibited functionally superior anti-tumor immunity. These results demonstrate that innate immune activation potentiates anti-tumor adaptive responses, highlighting the use of dual checkpoint blockade as an optimal strategy for promoting CD8+ T cell-mediated protection.

Retinoic acid and TGF-β orchestrate organ-specific programs of tissue residency

Tissue-resident memory T (TRM) cells are integral to tissue immunity, persisting in diverse anatomical sites where they adhere to a common transcriptional framework. How these cells integrate distinct local cues to adopt the common TRM cell fate remains poorly understood. Here, we show that whereas skin TRM cells strictly require transforming growth factor β (TGF-β) for tissue residency, those in other locations utilize the metabolite retinoic acid (RA) to drive an alternative differentiation pathway, directing a TGF-β-independent tissue residency program in the liver and synergizing with TGF-β to drive TRM cells in the small intestine. We found that RA was required for the long-term maintenance of intestinal TRM populations, in part by impeding their retrograde migration. Moreover, enhanced RA signaling modulated TRM cell phenotype and function, a phenomenon mirrored in mice with increased microbial diversity. Together, our findings reveal RA as a fundamental component of the host-environment interaction that directs immunosurveillance in tissues.