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Immunotherapy using immune checkpoint inhibitors (ICIs) has shown superior efficacy compared with conventional chemotherapy in certain cancer types, establishing immunotherapy as the fourth standard treatment alongside surgical intervention, chemotherapy, and radiotherapy. In cancer immunotherapy employing ICIs, CD8‐positive cytotoxic T lymphocytes are recognized as the primary effector cells. For effective clinical outcomes, it is essential that the targeted cancer cells express HLA class I molecules to present antigenic peptides derived from the tumor. However, cancer cells utilize various mechanisms to downregulate or lose HLA class I molecules from their surface, resulting in evasion from immune surveillance. Correlations between prognosis and the integrity of HLA class I molecules expressed by cancer cells have been consistently found across different types of cancer. This paper provides an overview of the regulatory mechanisms of HLA class I molecules and their role in cancer immunotherapy, with a particular emphasis on the significance of utilizing pathological tissues to evaluate HLA class I molecules expressed in cancer cells. [ABSTRACT FROM AUTHOR]

Malignant glioma is an aggressive primary brain tumor. Due to its location, the interactions of glioma and the immune system are complex. We start this paper by proposing a simple mathematical model that describes the interaction among glioma cells, microglia and cytotoxic T lymphocytes (CTLs). The existence and stability conditions of the equilibrium points are analyzed. Numerical results showed that neither microglia nor CTLs has the ability to eradicate the tumor. As a result, we extend the model by including the chemotherapeutic agent. The model has six equilibrium points, and one of these points represents a cured state. Through local stability, we found a range of values for the infusion rate that guarantees the elimination of glioma, as well as preventing the glioma from reoccurring. [ABSTRACT FROM AUTHOR]

Vitiligo is caused by an autoimmune reaction against melanocytes leading to melanocyte loss. The cause of vitiligo is an interaction between genetic susceptibility and environmental factors. Both the adaptive immune system—through cytotoxic CD8+ T cells and melanocyte specific antibodies—and the innate immune system are involved in these immune processes in vitiligo. While recent data stressed the importance of innate immunity in vitiligo, the question remains why vitiligo patients' immune response becomes overly activated. Could a long‐term increase in innate memory function, described as trained immunity after vaccination and in other inflammatory diseases, play a role as an enhancer and continuous trigger in the pathogenesis of vitiligo? After exposure to certain stimuli, innate immune system is able to show an enhanced immunological response to a secondary trigger, indicating a memory function of the innate immune system, a concept termed trained immunity. Trained immunity is regulated by epigenetic reprogramming, including histone chemical modifications and changes in chromatin accessibility that cause sustained changes in the transcription of specific genes. In responses to an infection, trained immunity is beneficial. However, there are indications of a pathogenic role of trained immunity in inflammatory and autoimmune diseases, with monocytes presenting features of a trained phenotype, resulting in increased cytokine production, altered cell metabolism through mTOR signaling, and epigenetic modifications. This hypothesis paper focusses on vitiligo studies that have shown these indications, suggesting the involvement of trained immunity in vitiligo. Future studies focusing on metabolic and epigenetic changes in innate immune cell populations in vitiligo could help in elucidating the potential role of trained immunity in vitiligo pathogenesis. [ABSTRACT FROM AUTHOR]

In this paper, we develop a diffusive and delayed hepatitis B virus (HBV) infection model, which incorporates both virus‐to‐cell and cell‐to‐cell transmissions along with cytotoxic T lymphocyte (CTL) immune response. Two threshold parameters ℜ0$$ {\mathfrak{\Re}}_0 $$ (basic reproduction number) and ℜ1$$ {\mathfrak{\Re}}_1 $$ (immune response reproduction number) are defined, which determine the dynamic behavior of the model. Employing the approach of Lyapunov functionals, we show that the infection‐free steady state is globally asymptotically stable when ℜ0≤1$$ {\mathfrak{\Re}}_0\le 1 $$; the immune‐free infected steady state is globally asymptotically stable when ℜ1≤1<ℜ0$$ {\mathfrak{\Re}}_1\le 1<{\mathfrak{\Re}}_0 $$; and the immune‐present steady state is globally asymptotically stable when ℜ0>1,ℜ1>1$$ {\mathfrak{\Re}}_0>1,{\mathfrak{\Re}}_1>1 $$, and φ(I)=I$$ \varphi (I)=I $$. We perform the sensitivity and uncertainly analysis on ℜ0$$ {\mathfrak{\Re}}_0 $$ with respect to parameters and find that the most important parameter that drives the HBV infection is the mortality of HBV DNA capsids. Moreover, the theoretical results are supported with numerical simulations. [ABSTRACT FROM AUTHOR]

According to the latest evidence, the microbial metabolite Urolithin A (UA), known for its role in promoting cellular health, modulates CD8+ T cell‐mediated antitumor activity. However, the direct target protein of UA and its underlying mechanism remains unclear. Here, this research identifies ERK1/2 as the specific target crucial for UA‐mediated CD8+ T cell activation. Even at low doses, UA markedly enhances the persistence and effector functions of primary CD8+ cytotoxic T lymphocytes (CTLs) and human chimeric antigen receptor (CAR) T cells both in vitro and in vivo. Mechanistically, UA interacts directly with ERK1/2 kinases, enhancing their activation and subsequently facilitating T cell activation by engaging ULK1. The UA‐ERK1/2‐ULK1 axis promotes autophagic flux in CD8+ CTLs, enhancing cellular metabolism and maintaining reactive oxygen species (ROS) levels, as evidenced by increased oxygen consumption and extracellular acidification rates. UA‐treated CD8+ CTLs also display elevated ATP levels and enhanced spare respiratory capacity. Overall, UA activates ERK1/2, inducing autophagy and metabolic adaptation, showcasing its potential in tumor immunotherapy and interventions for diseases involving ERKs. [ABSTRACT FROM AUTHOR]

Personalized cancer vaccines based on resected tumors from patients is promising to address tumor heterogeneity to inhibit tumor recurrence or metastasis. However, it remains challenge to elicit immune activation due to the weak immunogenicity of autologous tumor antigens. Here, a hybrid membrane cancer vaccine is successfully constructed by membrane fusion to enhance adaptive immune response and amplify personalized immunotherapy, which formed a codelivery system for autologous tumor antigens and immune adjuvants. Briefly, the functional hybrid vesicles (HM‐NPs) are formed by hybridizing ginseng‐derived extracellular vesicles‐like particles (G‐EVLPs) with the membrane originated from the resected autologous tumors. The introduction of G‐EVLPs can enhance the phagocytosis of autologous tumor antigens by dendritic cells (DCs) and facilitate DCs maturation through TLR4, ultimately activating tumor‐specific cytotoxic T lymphocytes (CTLs). HM‐NPs can indeed strengthen specific immune responses to suppress tumors recurrence and metastasis including subcutaneous tumors and orthotopic tumors. Furthermore, a long‐term immune protection can be obtained after vaccinating with HM‐NPs, and prolonging the survival of animals. Overall, this personalized hybrid autologous tumor vaccine based on G‐EVLPs provides the possibility of mitigating tumor recurrence and metastasis after surgery while maintaining good biocompatibility. [ABSTRACT FROM AUTHOR]

In this paper, using the methods of killing tumors and impulsive differential equations, two immunotherapy antitumor models for describing therapies of general tumors and advanced solid tumors are established. By using the theories of impulsive equations, small amplitude perturbation techniques, and the comparison technique, we obtain the conditions which guarantee the global asymptotical stability of the tumor‐eliminated periodic solution and system permanence, when immunotherapy alone is performed. The numerical results of the influences of the impulsive perturbation on the inherent oscillation show rich dynamics, such as period‐doubling bifurcation and chaos. Moreover, the effects of the combination of radiotherapy with immunotherapy on antitumor are obtained, including the threshold value of stability conditions of tumor‐eradication periodic solution when the mixed combination treatment of immunotherapy and radiotherapy is performed. Some numerical simulations for the effects of the timing of radiotherapy application and the timing of injection T cells on the threshold value are performed. Finally, we present some theoretical methods for suppressing the growth of tumors. [ABSTRACT FROM AUTHOR]

In this paper, we formulate a within‐host dynamics model for HIV/HTLV‐I co‐infection under the influence of cytotoxic T lymphocytes (CTLs). The model incorporates silent HIV‐infected CD4+T cells and silent HTLV‐infected CD4+T cells. The model includes two routes of HIV transmission, virus to cell (VTC) and cell to cell (CTC). It also incorporates two modes of HTLV‐I transmission, horizontal transmission via direct CTC contact and vertical transmission through mitotic division of Tax‐expressing HTLV‐infected cells. The model takes into account five types of distributed‐time delays. We analyze the model by proving the nonnegativity and boundedness of the solutions, calculating all possible equilibria, deriving a set of key threshold parameters, and proving the global stability of all equilibria. The global asymptotic stability of all equilibria is established by utilizing Lyapunov function and LaSalle's invariance principle. We present numerical simulations to justify the applicability and effectiveness of the theoretical results. In addition, we discuss the effect of HTLV‐I infection on the HIV dynamics and vice versa. [ABSTRACT FROM AUTHOR]

In this paper, the dynamics of stochastic human T‐cell leukemia virus type I (HTLV‐I) infection model with cytotoxic T lymphocyte (CTL) immune response is investigated. First, we show that the stochastic model exists as a unique positive global solution originating from the positive initial value. Second, we demonstrate that the stochastic model is stochastically permanent and stochastically ultimately bounded for any positive initial value. Third, we establish sufficient conditions for the existence of ergodic stationary distribution of the stochastic model. Fourth, the threshold R0∗ between extinction and persistence of the virus is obtained. Finally, numerical simulations are carried out to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

A two‐dimensional tumor‐immune model with the time delay of the adaptive immune response is considered in this paper. The model is designed to account for the interaction between cytotoxic T lymphocytes (CTLs) and cancer cells on the surface of a solid tumor. The model considers the surface growth as a major growth pattern of solid tumors in order to describe the existence of necrotic kernels. The qualitative analysis shows that the immune‐free equilibrium is unstable, and the behavior of positive equilibrium is closely related to the ratio of the immune killing rate to tumor volume growth rate. The positive equilibrium is locally asymptotically stable when the ratio is smaller than a critical value. Otherwise, the occurrence of the delay‐driven Hopf bifurcation at the positive equilibrium is proved. Applying the center manifold reduction and normal form method, we obtain explicit formulas to determine the properties of the Hopf bifurcation. The global continuation of a local Hopf bifurcation is investigated based on the coincidence degree theory. The results reveal that the time of the adaptive immune system taken to response to tumors can lead to oscillation dynamics. We also carry out detailed numerical analysis for parameters and numerical simulations to illustrate our qualitative analysis. Numerically, we find that shorter immune response time can lead to longer patient survival time, and the period and amplitude of a stable periodic solution increase with the increasing immune response time. When CTLs recruitment rate and death rate vary, we show how the ratio of the immune killing rate to tumor volume growth rate and the first bifurcation value change numerically, which yields further insights to the tumor‐immune dynamics. [ABSTRACT FROM AUTHOR]

This article explores the molecular characteristics and immune microenvironments of secondary radiation-exposed rectal cancers (SRCs) compared to primary rectal cancers (PRCs). The study used single-cell transcriptomic sequencing to analyze the cell type-specific profiles of 18 SRCs and identified distinct differences in copy number variation and immune cell composition between SRCs and PRCs. The findings suggest that oncogene amplification and the activation of Treg cells may promote the progression of SRCs, while the emergence of neutrophils and activation of macrophages contribute to the immune microenvironment of SRCs. The study provides valuable insights into the tumorigenesis of SRCs and potential therapeutic strategies. [Extracted from the article]

Immunotherapy targeting PD‐L1 is still ineffective for a wide variety of tumors with high unpredictability. Deploying combined immunotherapy with alternative targeting is practical to overcome this therapeutic resistance. Here, the deficiency of serine‐threonine kinase STK24 is observed in tumor cells causing substantial attenuation of tumor growth in murine syngeneic models, a process relying on cytotoxic CD8+ T and NK cells. Mechanistically, STK24 in tumor cells associates with and directly phosphorylates AKT at Thr21, which promotes AKT activation and subsequent PD‐L1 induction. Deletion or inhibition of STK24, by contrast, blocks IFN‐γ‐mediated PD‐L1 expression. Various murine models indicate that in vivo silencing of STK24 can significantly enhance the efficacy of the anti‐PD‐1 blockade strategy. Elevated STK24 levels are observed in patient specimens in multiple tumor types and inversely correlated with intratumoral infiltration of cytotoxic CD8+ T cells and with patient survival. The study collectively identifies STK24 as a critical modulator of antitumor immunity, which engages in AKT and PD‐L1/PD‐1 signaling and is a promising target for combined immunotherapy. [ABSTRACT FROM AUTHOR]

The liver is the most tolerogenic of transplanted organs. However, the mechanisms underlying liver transplant tolerance are not well understood. The comparison between liver transplantation tolerance and heart/kidney transplantation rejection will deepen our understanding of tolerance and rejection in solid organs. Here, we built a mouse model of liver, heart and kidney allograft and performed single-cell RNA sequencing of 66,393 cells to describe the cell composition and immune cell interactions at the early stage of tolerance or rejection. We also performed bulk RNA-seq of mouse liver allografts from Day 7 to Day 60 posttransplantation to map the dynamic transcriptional variation in spontaneous tolerance. The transcriptome of lymphocytes and myeloid cells were characterized and compared in three types of organ allografts. Cell-cell interaction networks reveal the coordinated function of Kupffer cells, macrophages and their associated metabolic processes, including insulin receptor signalling and oxidative phosphorylation in tolerance induction. Cd11b+ dendritic cells (DCs) in liver allografts were found to inhibit cytotoxic T cells by secreting anti-inflammatory cytokines such as Il10. In summary, we profiled single-cell transcriptome analysis of mouse solid organ allografts. We characterized the immune microenvironment of mouse organ allografts in the acute rejection state (heart, kidney) and tolerance state (liver). [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer‐related death worldwide. Hepatectomy remains the first‐line treatment for patients with resectable HCC. However, the reported recurrence rate of HCC at 5 years after surgery is between 50% and 70%. Tumor‐related factors, including tumor size, number and differentiation, and underlying liver disease are well‐known risk factors for recurrence after treatment. In addition to tumor‐related factors, ever‐increasing amounts of studies are finding that the tumor microenvironment also plays an important role in the recurrence of HCC, including systemic inflammatory response and immune regulation. Based on this, some inflammatory and immune markers were used in predicting postoperative cancer recurrence. These include neutrophil‐to‐lymphocyte ratio, platelet‐to‐lymphocyte ratio, cytotoxic T cells, and regulatory T cells, among others. In this review, we summarized the inflammatory and immune markers that affect recurrence after HCC resection in order to provide direction for adjuvant therapy after HCC resection and ultimately achieve the goal of reducing recurrence. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) has been widely employed in tumor treatment due to its effectiveness. However, the tumor hypoxic microenvironment which is caused by abnormal vasculature severely limits the efficacy of PDT. Furthermore, the abnormal vasculature has been implicated in the failure of immunotherapy. In this study, a novel nanoparticle denoted as Combo‐NP is introduced, composed of a biodegradable NIR II fluorescent pseudo‐conjugate polymer featuring disulfide bonds within its main chain, designated as TPA‐BD, and the vascular inhibitor Lenvatinib. Combo‐NP exhibits dual functionality by not only inducing cytotoxic reactive oxygen species (ROS) to directly eliminate tumor cells but also eliciting immunogenic cell death (ICD). This ICD response, in turn, initiates a robust cascade of immune reactions, thereby augmenting the generation of cytotoxic T lymphocytes (CTLs). In addition, Combo‐NP addresses the issue of tumor hypoxia by normalizing the tumor vasculature. This normalization process enhances the efficacy of PDT while concurrently fostering increased CTLs infiltration within the tumor microenvironment. These synergistic effects synergize to potentiate the photodynamic‐immunotherapeutic properties of the nanoparticles. Furthermore, when combined with anti‐programmed death‐ligand 1 (PD‐L1), they showcase notable inhibitory effects on tumor metastasis. The findings in this study introduce an innovative nanomedicine strategy aimed at triggering systemic anti‐tumor immune responses for the treatment of Uveal melanoma. [ABSTRACT FROM AUTHOR]

A key phenomenon in cancer is the establishment of a highly immunosuppressive tumour microenvironment (TME). Despite advances in immunotherapy, where the purpose is to induce tumour recognition and hence hereof tumour eradication, the majority of patients applicable for such treatment still fail to respond. It has been suggested that high immunological activity in the tumour is essential for achieving effective response to immunotherapy, which therefore have led to exploration of strategies that triggers inflammatory pathways. Here activation of the stimulator of interferon genes (STING) signalling pathway has been considered an attractive target, as it is a potent trigger of pro‐inflammatory cytokines and types I and III interferons. However, immunotherapy combined with targeted STING agonists has not yielded sustained clinical remission in humans. This suggests a need for exploring novel adjuvants to improve the innate immunological efficacy. Here, we demonstrate that extracellular vesicles (EVs), derived from activated CD4+ T cells (T‐EVs), sensitizes macrophages to elevate STING activation, mediated by IFNγ carried on the T‐EVs. Our work support that T‐EVs can disrupt the immune suppressive environment in the tumour by reprogramming macrophages to a pro‐inflammatory phenotype, and priming them for a robust immune response towards STING activation. [ABSTRACT FROM AUTHOR]

PF13: EV Heterogeneity 1 Chairs: Michael Harding, Andre Gorgens Location: Hall 4A 16:00 - 18:00 PF13.08 Comparisons of Tetraspanin profile of Extracellular Vesicles-derived from Sarcoma Cel... Thitikan Jirakittisonthon SP 1 sp ; Orman L. Snyder SP 2 sp ; Hong He SP 3 sp ; Mark Weiss SP 1 sp I SP 1 sp Kansas State University, Manhattan, USA; SP 2 sp Kansas State University, Topeka, USA; SP 3 sp Kansas State University, USA i B Introduction b : Based on Minimum Information for Studies of Extracellular Vesicles 2018 (MISEV 2018), characterization of EVs using transmembrane protein markers is one of the criteria for characterization. B Funding b : Funding was partly provided by NIH grants DP1DK126199, and DP2 EB028110-01 awarded to DGP B keywords b : Engineered EVs, immunomodulation, solid tumors, nonviral gene delivery, tissue nanotransfection PT17.13 Isolation of neuron-derived extracellular vesicles from biological fluids for the dia... Igor V. Kurochkin; Lausonia Ramaswamy I Sysmex Co., Kobe, Japan i B Introduction b : The molecular content of extracellular vesicles (EVs) largely reflects the content of cells of origin and thus analysis of neuron-derived EVs (NDEs) present in plasma offers a possibility of minimally invasive diagnosis of neurological disorders. B keywords b : Extracellular vesicles (EVs), MicroRNAs, Nonalcoholic fatty liver disease, Lipotoxicity, PT09: EVs from Microorganism 1 Chairs: Meta Kuehn, Irma Schabussova Location: Hall 4A 16:45 - 18:45 PT09.14 Examining the role of bacterial extracellular vesicles in host blood pressure regulat... Feiya Shi SP 1 sp ; Rishi Wagle SP 1 sp ; Sriram Ayyaswamy SP 1 sp ; DAVID DURGAN SP 2 sp I SP 1 sp Baylor College of Medicine, USA; SP 2 sp Baylor College of Medicine, Houston, USA i B Introduction b : We have previously demonstrated that disruption of the normal gut microbiota composition, termed gut dysbiosis, is an underlying cause of hypertension (HT). [Extracted from the article]

Effective vaccines have reduced the morbidity and mortality caused by severe acute respiratory syndrome coronavirus‐2 infection; however, the elderly remain the most at risk. Understanding how vaccines generate protective immunity and how these mechanisms change with age is key for informing future vaccine design. Cytotoxic CD8+ T cells are important for killing virally infected cells, and vaccines that induce antigen‐specific CD8+ T cells in addition to humoral immunity provide an extra layer of immune protection. This is particularly important in cases where antibody titers are suboptimal, as can occur in older individuals. Here, we show that in aged mice, spike epitope–specific CD8+ T cells are generated in comparable numbers to younger animals after ChAdOx1 nCoV‐19 vaccination, although phenotypic differences exist. This demonstrates that ChAdOx1 nCoV‐19 elicits a good CD8+ T‐cell response in older bodies, but that typical age‐associated features are evident on these vaccine reactive T cells. [ABSTRACT FROM AUTHOR]

Background: Bladder cancer (BLCA) is one of the most diagnosed cancers in humans worldwide. Recently, immunotherapy has become a main treatment option for BC. However, most BLCA patients do not respond to immune checkpoint inhibitors or relapse after immunotherapy. Therefore, it is very important to identify novel biomarkers for the prediction of immunotherapy response in B patients. Methods: Pancancer single‐cell RNA sequencing (scRNA‐seq) data were used to identify the clusters of CD4+ T cells in the tumour microenvironment (TME). The clinical significance of key CD4+ T‐cell clusters was evaluated based on the survival data of two independent immunotherapy bladder cancer (BLCA) cohorts. We also investigated the function of key clusters of CD4+ T cell in the TME of BC cells in vitro. Results: This study identified two novel exhausted CD4+ T‐cell subpopulations with the expression of PD1hi CD200hi or PD1hi CD200low in BC patients. Moreover, BLCA patients with a high level of PD1hi CD200hi CD4+ exhausted T cell showed immunotherapy resistance. Cell function analysis demonstrated that PD1hi CD200hi CD4+ exhausted T cell can promote epithelial–mesenchymal transition (EMT) and angiogenesis in BLCA cells. In addition, PD1hi CD200hi CD4+ exhausted T cells were shown to communicate with malignant BLCA cells through the GAS6–AXL axis. Finally, we also found that GAS6 expression is upregulated in B cells by METTL3‐mediated m6A modification. Conclusions: PD1hi CD200hi CD4+ exhausted T cell may serve as a novel biomarker for poor prognosis and immunotherapy resistance in B. Targeted inhibitors of PD1hi CD200hi CD4+ exhausted T cells may help improve the efficacy of immunotherapy. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T‐cell therapy is an immunotherapy approach that has played a tremendous role in the battle against cancer for years. Since the CAR T lymphocytes are unrestricted‐major histocompatibility complex T lymphocytes, they could identify more targets than natural T cells, resulting in practical and widespread functions. The good prospects of CAR T‐cell therapy in oncology can be additionally applied to treat other diseases such as autoimmune and infectious diseases. CAR‐T cell‐derived immunotherapy for autoimmune disorders can be allocated to CAR‐Tregs and chimeric autoantibody receptor T cells. Other generations of CARs target human immunodeficiency virus (HIV) proteins. In this review, we summarize CAR‐T cell therapies in autoimmune disorders and HIV infection. [ABSTRACT FROM AUTHOR]

High‐frequency mutation of the TP53 tumor suppressor gene is observed in multiple human cancers, which promotes cancer progression. However, the mutated gene‐encoded protein may serve as a tumor antigen to elicit tumor‐specific immune responses. In this study, we detected widespread expression of shared TP53‐Y220C neoantigen in hepatocellular carcinoma with low affinity and low stability of binding to HLA‐A0201 molecules. We substituted the amino acid sequences VVPCEPPEV with VLPCEPPEV in the TP53‐Y220C neoantigen to yield a TP53‐Y220C (L2) neoantigen. This altered neoantigen was found to increase affinity and stability and induce more cytotoxic T lymphocytes (CTLs), indicating improvements in immunogenicity. In vitro assays showed the cytotoxicity of CTLs stimulated by both TP53‐Y220C and TP53‐Y220C (L2) neoantigens against multiple HLA‐A0201‐positive cancer cells expressing TP53‐Y220C neoantigens; however, the TP53‐Y220C (L2) neoantigen showed higher cytotoxicity than the TP53‐Y220C neoantigen against cancer cells. More importantly, in vivo assays demonstrated greater inhibition of hepatocellular carcinoma cell proliferation by TP53‐Y220C (L2) neoantigen‐specific CTLs relative to TP53‐Y220C neoantigen in zebrafish and nonobese diabetic/severe combined immune deficiency mouse models. The results of this study demonstrate enhanced immunogenicity of the shared TP53‐Y220C (L2) neoantigen, which has the potential as dendritic cells or peptide vaccines for multiple cancers. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus has been widely reported to be majorly responsible for causing nosocomial infections worldwide. Due to an increase in antibiotic‐resistant strains, the development of an effective vaccine against the bacteria is the most viable alternative. Therefore, in the current work, an effort has been undertaken to develop a novel peptide‐based vaccine construct against S aureus that can potentially evoke the B and T cell immune responses. The fibronectin‐binding proteins are an attractive target as they play a prominent role in bacterial adherence and host cell invasion and are also well conserved among rapidly mutating pathogens. Therefore, highly immunogenic linear B lymphocytes (LBL), cytotoxic T lymphocytes (CTL), and helper T lymphocytes (HTL) epitopes were identified from the antigenic fibronectin‐binding proteins A and B (FnBPA and FnBPB) of S aureus using immunoinformatics approaches. The selected peptides were confirmed to be non‐allergenic, non‐toxic, and with a high binding affinity to the majority of human leukocyte antigens (HLA) alleles. Consequently, the multi‐peptide vaccine construct was developed by fusing the screened epitopes (three LBL, five CTL, and two HTL) together with the suitable adjuvant and linkers. In addition, the tertiary conformation of the peptide construct was modeled and later docked to the Toll‐like receptor 2. Subsequently, a molecular dynamics simulation of 100 ns was employed to corroborate the stability of the designed vaccine‐receptor complex. Besides exhibiting high immunogenicity and conformational stability, the developed vaccine was observed to possess wide population coverage of 99.51% worldwide. Additional in vivo and in vitro validation studies would certainly corroborate the designed vaccine construct to have improved prophylactic efficacy against S aureus. Staphylococcus aureus is a major cause of nosocomial infections worldwide, and the development of an effective vaccine against it is the most viable alternative. This work has been undertaken to develop a novel peptide‐based vaccine construct against S. aureus that can evoke the B and T cell immune responses. [ABSTRACT FROM AUTHOR]

Materials‐based antigen delivery systems can augment the immune response by improving antigen uptake in antigen‐presenting cells, targeting lymph nodes, prolonging antigen exposure, enhancing cross‐presentation, etc. Recent research revealed that some antigen carriers activate the innate immune pathways without additional adjuvant. Here, a vaccine delivery platform (antigen nanocapsules) constructed by a one‐step in situ polymerization is reported, weaving a biodegradable polymer network around the antigen surface. This simple technology allowed us to study the immunomodulatory effect of various antigen carriers. An antigen nanocapsule (NC7) capable of inducing dendritic cell activation and cross‐presentation is identified. Further mechanistic studies revealed that NC7 activated the cGAS‐STING pathway in a cGAS‐dependent manner. Moreover, the subcutaneously injected NC7 accumulated in the lymph nodes and elicited strong cytotoxic T cell immunity and T cell memory against established cancer. Collectively, the often‐neglected immunomodulatory effect of various cationic antigen carriers, enabling potential application in cancer vaccines, is uncovered. [ABSTRACT FROM AUTHOR]

Two major chaperones, calreticulin (CRT) and binding immunoglobulin protein (GRP78/BiP) dependent on their location, have immunoregulatory or anti‐inflammatory functions respectively. CRT induces pro‐inflammatory cytokines, dendritic cell (DC) maturation and activates cytotoxic T cells against tumours. By contrast, GRP78/BiP induces anti‐inflammatory cytokines, inhibits DC maturation and heightens T‐regulatory cell responses. These latter functions rebalance immune homeostasis in inflammatory diseases, such as rheumatoid arthritis. Both chaperones are therapeutically relevant agents acting primarily on monocytes/DCs. Endogenous exposure of CRT on cancer cell surfaces acts as an 'eat‐me' signal and facilitates improved elimination of stressed and dying tumour cells by DCs. Therefore, therapeutics that promote endogenous CRT translocation to the cell surface can improve the removal of cancer cells. However, infused recombinant CRT dampens this cancer cell eradication by binding directly to the DCs. Low levels of endogenous BiP appear as a surface biomarker of endoplasmic reticulum (ER) stress in some types of tumour cells, a reflection of cells undergoing proliferation, in which resulting hypoxia and nutrient deprivation perturb ER homeostasis triggering the unfolded protein response, leading to increased expression of GRP78/BiP and altered cellular location. Conversely, infusion of an analogue of GRP78/BiP (IRL201805) can lead to long‐term immune resetting and restoration of immune homeostasis. The therapeutic potential of both chaperones relies on them being relocated from their intracellular ER environment. Ongoing clinical trials are employing therapeutic interventions to either enhance endogenous cell surface CRT or infuse IRL201805, thereby triggering several disease‐relevant immune responses leading to a beneficial clinical outcome. [ABSTRACT FROM AUTHOR]

Applying the CyTOF technology on AD blood cells identified mainly NK and T cell subpopulations. In conclusion, mass cytometry-based immune cell profiling revealed the presence of immune cell subsets of different lineages including eosinophils, NK, NKT and activated T cell populations, which may contribute to AD pathophysiology. [Extracted from the article]

Distinct thermal therapies have been used for cancer therapy. For hyperthermia (HT) treatment the tumour tissue is heated to temperatures between 39 and 45°C, while during ablation (AB) temperatures above 50°C are achieved. HT is commonly used in combination with different treatment modalities, such as radiotherapy and chemotherapy, for better clinical outcomes. In contrast, AB is usually used as a single modality for direct tumour cell killing. Both thermal therapies have been shown to result in cytotoxicity as well as immune response stimulation. Immunogenic responses encompass the innate and adaptive immune systems and involve the activation of macrophages, dendritic cells, natural killer cells and T cells. Several heat technologies are used, but great interest arises from nanotechnology‐based thermal therapies. Spontaneous tumours in dogs can be a model for cancer immunotherapies with several advantages. In addition, veterinary oncology represents a growing market with an important demand for new therapies. In this review, we will focus on nanoparticle‐mediated thermal‐induced immunogenic effects, the beneficial potential of integrating thermal nanomedicine with immunotherapies and the results of published works with thermotherapies for cancer using dogs with spontaneous tumours, highlighting the works that evaluated the effect on the immune system in order to show dogs with spontaneous cancer as a good model for evaluated the immunomodulatory effect of nanoparticle‐mediated thermal therapies. [ABSTRACT FROM AUTHOR]

Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells recognize and eliminate cancer cells. However, immune evasion, downregulation of immune function by the tumour microenvironment and resistance of cancer cells are major problems. Although CTL and NK cells are both important to eliminate cancer, most studies address them individually. We quantified sequential primary human CTL and NK cell cytotoxicity against the melanoma cell line SK‐Mel‐5. At high effector‐to‐target ratios, NK cells or melan‐A (MART‐1)‐specific CTL eliminated all SK‐Mel‐5 cells within 24 h, indicating that SK‐Mel‐5 cells are not resistant initially. However, at lower effector‐to‐target ratios, which resemble numbers of the immune contexture in human cancer, a substantial number of SK‐Mel‐5 cells survived. Pre‐exposure to CTL induced resistance in surviving SK‐Mel‐5 cells to subsequent CTL or NK cell cytotoxicity, and pre‐exposure to NK cells induced resistance in surviving SK‐Mel‐5 cells to NK cells. Higher human leucocyte antigen class I expression or interleukin‐6 levels were correlated with resistance to NK cells, whereas reduction in MART‐1 antigen expression was correlated with reduced CTL cytotoxicity. The CTL cytotoxicity was rescued beyond control levels by exogenous MART‐1 antigen. In contrast to the other three combinations, CTL cytotoxicity against SK‐Mel‐5 cells was enhanced following NK cell pre‐exposure. Our assay allows quantification of sequential CTL and NK cell cytotoxicity and might guide strategies for efficient CTL–NK cell anti‐melanoma therapies. Key points: Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells eliminate cancer cells. Both CTL and NK cells attack the same targets, but most studies address them individually.In a sequential cytotoxicity model, the interdependence of antigen‐specific CTL and NK cell cytotoxicity against melanoma is quantified.High numbers of antigen‐specific CTL and NK cells eliminate all melanoma cells. However, lower numbers induce resistance if secondary CTL or NK cell exposure follows initial CTL exposure or if secondary NK cell exposure follows initial NK cell exposure. On the contrary, if secondary CTL exposure follows initial NK cell exposure, cytotoxicity is enhanced.Alterations in human leucocyte antigen class I expression and interleukin‐6 levels are correlated with resistance to NK cells, whereas a reduction in antigen expression is correlated with reduced CTL cytotoxicity; CTL cytotoxicity is rescued beyond control levels by exogenous antigen.This assay and the results on interdependencies will help us to understand and optimize immune therapies against cancer. [ABSTRACT FROM AUTHOR]

The relative abundance of myeloid‐derived suppressor cells (MDSCs) compared to cytotoxic T cells determines the outcomes of diseases and the efficacy of immunotherapy. Ubiquitin‐specific peptidase 12 (USP12), a member of the USP family of deubiquitinases, targets multiple signalling pathways and regulates diverse biological processes, including cell proliferation and survival. It is well known that ubiquitylation is an important mechanism for regulating the immune response. However, it is unclear whether USP12 regulates tumour growth by influencing MDSCs. In the present study, we reported that USP12 deficiency decreased infiltration and impaired the suppressor function of monocytic (M)‐MDSCs, resulting in increased CD8+ T‐cell response and decelerated tumour growth. USP12‐knockout M‐MDSCs were less potent in inhibiting the proliferation of CD8+ T cells and their ability to secrete IFN‐γ. Furthermore, USP12 deficiency inhibited the suppressor function of M‐MDSCs by downregulating the negative regulatory molecules inducible nitric oxide synthase and PD‐L1, through deubiquitinating and stabilizing p65. Our results suggest that USP12 is a positive regulator of M‐MDSCs and may serve as a potential target for antitumor therapy. [ABSTRACT FROM AUTHOR]

Afterward, N SB 52-59 sb -specific T cells were fluorescence-activated cell sorting-based isolated from the spleen and transferred to new hosts bearing the CD45.2 genetic marker, to facilitate discrimination between transferred antigen-specific T cells and I de novo i -generated host antigen-specific T cells. Keywords: adaptive immunity; immune memory; memory T-cell; T-cell EN adaptive immunity immune memory memory T-cell T-cell 374 376 3 05/03/23 20230501 NES 230501 T-cell memory is considered long-lasting, but new evidence recently published in I Nature i by Soerens I et al i . shows that, under certain conditions, mouse memory T-cell immunity can span several mouse lifetimes. Age is just a number: long-lasting T-cell immunity can span several lifetimes. [Extracted from the article]

Aim: The clinical efficacy of chemoradiotherapy (CRT) is largely dependent on host immune status. The aim of this study was to identify possible markers expressed on circulating mononuclear cells to predict tumour response in patients with locally advanced rectal cancer (LARC). Methods: Peripheral blood samples were obtained from 47 patients diagnosed with LARC before and after CRT. The numbers of lymphocytes and monocyte subsets were analysed using flow cytometry. Based on clinical and pathological findings, patients were classified as high or low responders. Results: Lymphocyte counts were markedly decreased after CRT. Total numbers of lymphocytes (p = 0.030) and CD4(+) T cells (p = 0.041) in post‐CRT samples were significantly lower in low responders than in high responders. In contrast, monocyte counts were not reduced and the number of CD14dim(+) CD16(+) nonclassical (patrolling) monocytes were somewhat increased after CRT (p = 0.050). Moreover, the ratios of programmed cell death ligand 1 (PD‐L1) (+) cells on patrolling monocytes before and after CRT were significantly higher in low responders than in high responders (p = 0.0046, p = 0.0006). The same trend was observed for classical and intermediate monocytes. The expression of PD‐L1 on patrolling monocytes before CRT correlated inversely with the number of T cells and natural killer (NK) cells after CRT. PD‐L1(+) ratio in patrolling monocytes was an independent predictor for response to CRT. Conclusion: Programmed cell death ligand 1 (PD‐L1) expression on patrolling monocytes suppresses cell‐mediated immunity in patients receiving CRT which could be related to tumour response, and may be a useful biomarker for decision‐making in the management of patients with LARC. [ABSTRACT FROM AUTHOR]

Background: Emergence of dysplastic haematopoietic precursor/s, cytopenia and variable leukaemia risk characterise myelodysplastic syndromes (MDS). Impaired immune‐regulation, preferentially affecting cytotoxic T cells (CTL), has been largely observed in MDS. Recently, we described the TR3−56 T cell subset, characterised by the co‐expression of CD3 and CD56, as a novel immune‐regulatory population, able to modulate cytotoxic functions. Here, we address the involvement of TR3−56 cells in MDS pathogenesis/progression. Objectives: To analyse the relationship between TR3−56 and CTL activation/expansion in bone marrow (BM) of very‐low/low‐risk MDS subjects. Methods: Peripheral blood and BM specimens, obtained at disease onset in a cohort of 58 subjects, were analysed by immune‐fluorescence and flow cytometry, to preserve the complexity of the biological sample. Results: We observed that a trend‐increase of BM TR3−56 in high/very‐high MDS stage, as compared with very‐low/low group, associates with a decreased activation of BM resident CTL; significant correlation of TR3−56 with BM blasts has been also revealed. In addition, in very‐low/low‐risk subjects the TR3−56 amount in BM inversely correlates with the presence of activated BM CTL showing a skewed Vβ T‐cell repertoire. Conclusions: These data add TR3−56 to the immune‐regulatory network involved in MDS pathogenesis/progression. Better knowledge of the immune‐mediated processes associated with the disease might improve MDS clinical management. [ABSTRACT FROM AUTHOR]

Inosine is proven to promote the proliferation and function of CD8+ cytotoxic lymphocytes (CD8+ T) under glucose restriction and enhance the efficacy of programmed cell death protein ligand‐1 (PD‐L1) blockade therapy. However, systemic administration of high frequencies and large doses of inosine and anti‐PD‐L1 antibody (aPDL1) is required, which inevitably reduces bioavailability and causes severe immunological side effects. Therefore, it is crucial to develop a drug delivery system to achieve gradient release of inosine and aPDL1 for local immunotherapy. In this study, an inosine‐based supramolecular hydrogel, inosine‐phenylenediboronic‐isoguanosine (IPBisoG), is successfully developed following a simple one‐pot procedure. Both in vitro and in vivo studies demonstrate that the biocompatible and biodegradable IPBisoG hydrogel displays excellent stability and self‐healing properties. Furthermore, the IPBisoG hydrogel is shown to achieve the gradual and sequential release of inosine and aPDL1. Inosine, which enhances the proliferation and function of CD8+ T cells, together with aPDL1, the blocker of the immunosuppressive pathway in tumor microenvironment, can highly enhance the in vivo efficacy of PD‐L1 blockade therapy. The employment of IPBisoG hydrogel is also shown to trigger systemic immune responses. These results demonstrate that IPBisoG hydrogel can be a promising platform for tumor‐local immunotherapy in the future. [ABSTRACT FROM AUTHOR]

Tumor immunotherapy is only effective in a fraction of patients due to a low response rate and severe side effects, and these challenges of immunotherapy in clinics can be addressed through induction of immunogenic cell death (ICD). ICD is elicited from many antitumor therapies to release danger associated molecular patterns (DAMPs) and tumor‐associated antigens to facilitate maturation of dendritic cells (DCs) and infiltration of cytotoxic T lymphocytes (CTLs). The process can reverse the tumor immunosuppressive microenvironment to improve the sensitivity of immunotherapy. Nanostructure‐based drug delivery systems (NDDSs) are explored to induce ICD by incorporating therapeutic molecules for chemotherapy, photosensitizers (PSs) for photodynamic therapy (PDT), photothermal conversion agents for photothermal therapy (PTT), and radiosensitizers for radiotherapy (RT). These NDDSs can release loaded agents at a right dose in the right place at the right time, resulting in greater effectiveness and lower toxicity. Immunotherapeutic agents can also be combined with these NDDSs to achieve the synergic antitumor effect in a multi‐modality therapeutic approach. In this review, NDDSs are harnessed to load multiple agents to induce ICD by chemotherapy, PDT, PTT, and RT in combination of immunotherapy to promote the therapeutic effect and reduce side effects associated with cancer treatment. [ABSTRACT FROM AUTHOR]

Inadequate β‐cell mass is essential for the pathogenesis of type 2 diabetes (T2D). Previous report showed that an immunomodulator FTY720, a sphingosine 1‐phosphate (S1P) receptor modulator, sustainably normalized hyperglycemia by stimulating β‐cell in vivo regeneration in db/db mice. We further examined the effects of FTY720 on glucose homeostasis and diabetic complications in a translational nonhuman primate (NHP) model of spontaneously developed diabetes. The male diabetic cynomolgus macaques of 18–19 year old were randomly divided into Vehicle (Purified water, n = 5) and FTY720 (5 mg/kg, n = 7) groups with oral gavage once daily for 10 weeks followed by 10 weeks drug free period. Compared with the Vehicle group, FTY720 effectively lowered HbA1c, blood concentrations of fasting glucose (FBG) and insulin, hence, decreased homeostatic model assessment of insulin resistance (HOMA‐IR); ameliorated glucose intolerance and restored glucose‐stimulated insulin release, indicating rejuvenation of β‐cell function in diabetic NHPs. Importantly, after withdrawal of FTY720, FBG, and HbA1c remained at low level in the drug free period. Echocardiography revealed that FTY720 significantly reduced proteinuria and improved cardiac left ventricular systolic function measured by increased ejection fraction and fractional shortening in the diabetic NHPs. Finally, flow cytometry analysis (FACS) detected that FTY720 significantly reduced CD4 + and CD8 + T lymphocytes as well as increased DC cells in the circulation. Immunomodulator FTY720 improves glucose homeostasis via rejuvenation of β‐cell function, which can be mediated by suppression of cytotoxic CD8 + T lymphocytes to β‐cells, thus, may be a novel immunotherapy to reverse T2D progression and ameliorate the diabetic complications. [ABSTRACT FROM AUTHOR]

Immunotherapy became a key pillar of cancer therapeutics with the approvals of ipilimumab, nivolumab, and pembrolizumab, which inhibit either cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4) or programmed death‐1 (PD‐1) that are negative regulators of T‐cell activation. However, boosting T‐cell activation is often accompanied by autoimmunity, leading to adverse drug reactions (ADRs), including high grade 3–4 colitis and its severe complications whose prevalence may reach 14% for combination checkpoint inhibitors. In this research, we investigated how mechanistic differences between anti‐CTLA‐4 (ipilimumab) and anti‐PD‐1 (nivolumab and pembrolizumab) affect colitis, a general class toxicity. The data analytical platform Molecular Health Effect was utilized to map population ADR data from the US Food and Drug Administration (FDA) Adverse Event Reporting System to chemical and biological databases for hypothesis generation regarding the underlying molecular mechanisms causing colitis. Disproportionality analysis was used to assess the statistical relevance between adverse events of interest and molecular causation. We verified that the anti‐CTLA‐4 drug is associated with an approximately three‐fold higher proportional reporting ratio associated with colitis than those of the anti‐PD‐1 drugs. The signal of the molecular mechanisms, including signaling pathways of inflammatory cytokines, was statistically insignificant to test the hypothesis that the severer rate of colitis associated with ipilimumab would be due to a greater magnitude of T‐cell activation as a result of earlier response of the anti‐CTLA‐4 drug in the immune response. This patient‐centered systems‐based approach provides an exploratory process to better understand drug pair adverse events at pathway and target levels through reverse translation from postmarket surveillance safety reports. [ABSTRACT FROM AUTHOR]

SPHK1 (sphingosine kinase-1) catalyzes the phosphorylation of sphingosine to sphingosine-1-phosphate (S1P), is found to be highly expressed in solid tumors. Here, extracellular vesicles (EVs) are identified as the key transporters of SPHK1 to the tumor microenvironment. Consequently, SPHK1-packaged EVs elevate S1P levels in the tumor microenvironment, where S1P appears as an immunosuppressive agent. However, the exact mechanism of how S1P mediates its immunosuppressive effects in cancer is not understood. It is investigated that S1P can induce T cell exhaustion. S1P can also upregulate programmed death ligand-1 (PDL-1) expression through E2F1-mediated transcription. Notably, an SPHK1 inhibitor PF543 improves T cell-mediated cytotoxicity. Furthermore, combining PF543 with an anti-PD-1 antibody reduces tumor burden and metastasis more effectively than PF543 alone in vivo. These data demonstrate a previously unrecognized mechanism of how SPHK1-packaged EVs contribute to the progression of ovarian cancer and thus present the potential clinical application of inhibiting SPHK1/S1P signaling to improve immune checkpoint blockage (anti-PD-1 antibody) therapy in ovarian cancer. [ABSTRACT FROM AUTHOR]

The pathogenic immune response in celiac disease (CeD) is orchestrated by phenotypically distinct CD4+ T cells that recognize gluten epitopes in the context of disease‐associated HLA‐DQ allotypes. Cells with the same distinct phenotype, but with elusive specificities, are increased across multiple autoimmune conditions. Here, whether sorting of T cells based on their distinct phenotype (Tphe cells) yields gluten‐reactive cells in CeD is tested. The method′s efficiency is benchmarked by parallel isolation of gluten‐reactive T cells (Ttet cells), using HLA‐DQ:gluten peptide tetramers. From gut biopsies of 12 untreated HLA‐DQ2.5+ CeD patients, Ttet+/Tphe+, Ttet−/Tphe+, and Ttet−/Tphe− cells are sorted for single‐cell T‐cell receptor (TCR)‐sequencing (n = 8) and T‐cell clone (TCC)‐generation (n = 5). The generated TCCs are TCR sequenced and tested for their reactivity against deamidated gluten. Gluten‐reactivity is observed in 91.2% of Ttet+/Tphe+ TCCs, 65.3% of Ttet−/Tphe+ TCCs and 0% of Ttet−/Tphe− TCCs. TCR sequencing reveals clonal expansion and sequence sharing across patients, features reflecting antigen‐driven responses. The feasibility to isolate antigen‐specific CD4+ T cells by the sole use of phenotypic markers in CeD outlines a potential avenue for characterizing disease‐driving CD4+ T cells in autoimmune conditions. [ABSTRACT FROM AUTHOR]

Background: Maintenance with "everolimus + reduced dose tacrolimus" (Ev + Taclow) was reported to reduce the risk of viral infections compared to "tacrolimus + mycophenolate mofetil" (Tac + MMF). Here we examined viremia and viral‐specific T‐cell (viral‐Tc) responses in patients treated with Ev + Taclow versus Tac + MMF in highly‐human leukocyte antigen (HLA)‐sensitized patients. Methods: HLA‐sensitized (HS) kidney transplant patients were monitored pre‐ and post‐transplant for viremia (cytomegalovirus (CMV), BK, and Epstein–Barr virus (EBV)) by polymerase chain reaction (PCR) in 19 Ev + Taclow and 48 Tac + MMF patients. For CMV PCR analysis, we compared infection rates in 19 Ev + Taclow patients to 48 CMV D+/R‐ (#28) or CMV D‐/R‐ (#20) Tac + MMF patients. CMV‐specific cytotoxic T cell (CMV‐Tc) and EBV‐specific cytotoxic T cell (EBV‐Tc) were evaluated by cytokine flow cytometry, and donor‐specific antibody (DSA) levels by Luminex for selected patients in both groups. Results: CMV and EBV viremia rates were similar in Ev + Taclow versus Tac + MMF patients, but BK virus (BKV) rates were significantly higher in Ev + Taclow patients. No patient in either group developed BK virus‐associated allograft nephropathy (BKAN) or post‐transplant lymphoproliferative disorders (PTLD). CMV‐Tc and EBV‐Tc decreased significantly after alemtuzumab induction but returned to pre‐treatment levels 1–2 months post‐transplant in most patients. de novo DSA was similar in both groups as were patient and graft survival and graft rejection. Conclusions: CMV‐Tc and EBV‐Tc were similar in Ev + Taclow and Tac + MMF patients. EBV and CMV viremia rates were similar over 1 year. BKV rates were significantly higher in Ev + Taclow patients suggesting no benefit for Ev + Taclow in enhancing viral‐Tc effector functions or limiting viral infections. [ABSTRACT FROM AUTHOR]

Aims: Angioimmunoblastic T‐cell lymphoma (AITL) is genetically characterized by TET2 and DNMT3A mutations occurring in haematopoietic progenitor cells, and late events (e.g. the RHOA‐G17V mutation) associated with malignant transformation. As TET2/DNMT3A‐mutated progenitor cells can differentiate into multilineage progenies and give rise to both AITL and myeloid neoplasms, they may also have the potential to lead to other metachronous/synchronous neoplasms. We report two cases showing parallel evolution of two distinct potentially neoplastic lymphoid proliferations from a common mutated haematopoietic progenitor cell population. Methods and results: Both cases presented with generalized lymphadenopathy. In case 1 (a 67‐year‐old female), an initial lymph node (LN) biopsy was dismissed as reactive, but a repeat biopsy showed a nodal marginal zone lymphoma (NMZL)‐like proliferation with an increase in the number of T‐follicular helper (TFH) cells. Immunohistochemistry, and clonality and mutational analyses by targeted sequencing of both whole tissue sections and microdissected NMZL‐like lesions, demonstrated a clonal B‐cell proliferation that harboured the BRAF‐G469R mutation and shared TET2 and DNMT3A mutations with an underlying RHOA‐G17V‐mutant TFH proliferation. Review of the original LN biopsy showed histological and immunophenotypic features of AITL. In case 2 (a 66‐year‐old male), cytotoxic T‐cell lymphoma with an increase in the number of Epstein–Barr virus‐positive large B cells was diagnosed on initial biopsy. On review together with the relapsed biopsy, we identified an additional occult neoplastic TFH proliferation/smouldering AITL. Both T‐cell proliferations shared TET2 and DNMT3A mutations while RHOA‐G17V was confined to the smouldering AITL. Conclusions: In addition to demonstrating diagnostic challenges, these cases expand the potential of clonal haematopoiesis in the development of different lineage neoplastic proliferations. [ABSTRACT FROM AUTHOR]

A mathematical model of the tumor–immune system interactions is presented. The model includes the primary cell populations involved in CD4+ T cells mediated regression of the tumor, that is, tumor cells, CD4+ T cells, anti‐tumor cytokines, CTLA‐4 molecules, and normal cells. Our study reveals that host cells together with cytokines are key features in driving tumor dynamics. The malignant tumor can be completely suppressed if the tumor growth rate is small and the host cells are more competitive. No treatments are needed in this scenario as tumor cells are driven to extinction by host cells. We examine various immunotherapies of either T cells, anti‐tumor cytokines, anti‐CTLA‐4, or a combination of these to study their effectiveness. For the tumor with a medium growth rate and a moderate competitive ability to host cells, numerical simulations show that the host cells impel the tumor cells to demise due to battle with the normal cells and the effective jointed treatment strategy. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are crucial for the appropriate initiation of adaptive immune responses. During inflammation, DCs capture antigens, mature, and migrate to lymphoid tissues to present foreign material to naïve T cells. These cells get activated and differentiate either into pathogen‐specific cytotoxic CD8+ T cells that destroy infected cells or into CD4+ T helper cells that, among other effector functions, orchestrate antibody production by B cells. DC‐mediated antigen presentation is equally important in non‐inflammatory conditions. Here, DCs mediate induction of tolerance by presenting self‐antigens or harmless environmental antigens and induce differentiation of regulatory T cells or inactivation of self‐reactive immune cells. Detailed insights into the biology of DCs are, therefore, crucial for the development of novel vaccines as well as the prevention of autoimmune diseases. As in many other life science areas, our understanding of DC biology would be extremely restricted without bioimaging, a compilation of methods that visualize biological processes. Spatiotemporal tracking of DCs relies on various imaging tools, which not only enable insights into their positioning and migration within tissues or entire organs but also allow visualization of subcellular and molecular processes. This review aims to provide an overview of the imaging toolbox and to provide examples of diverse imaging techniques used to obtain fundamental insights into DC biology. [ABSTRACT FROM AUTHOR]

Humoral and cellular responses to viral infections coexist in a dynamic equilibrium that often results in efficient viral clearance. However, in some infections one of the two responses prevails, for instance when an overactivation of cytotoxic T cells is accompanied by weak and insufficient antibody responses. Although the cellular response is usually sufficient to control a primary viral infection, in some cases clearance is not complete and persistent infections ensue. In order to design effective therapeutic or vaccination strategies aiming at inducing early and potent neutralizing antibody responses, a deep knowledge of the cellular and molecular determinants of antiviral immune responses is needed. Here, we review our understanding on the spatiotemporal dynamics of antiviral humoral immune responses, with a particular focus on recent studies using intravital imaging approaches as an insightful complement to more traditional techniques. [ABSTRACT FROM AUTHOR]

Human leukocyte antigens (HLA) have been linked to adverse drug reactions. Generally, HLA association is phenotype specific and is related to either liver or skin injury. HLA‐A*13:01 has been linked to dapsone‐induced severe cutaneous drug reactions and its role in drug‐induced liver injury (DILI) is unclear. In our series, all of the four patients with immunoallergic dapsone DILI were carrying HLA‐B*13:01 compared to its prevalence of 1–12% among Indians. HLA‐B*13:01 plays a role not only in dapsone‐induced severe cutaneous adverse reaction (SCAR) but also in dapsone‐induced liver injury with immunoallergic features and highlights the role of adaptive immune response in the pathogenesis of both liver and skin injury and associated other organ involvement. [ABSTRACT FROM AUTHOR]

T‐cell‐based immunotherapy and immune checkpoint blockade have been successfully used to treat several human solid cancers. The present study attempted to investigate the feasibility and efficacy of the antitumor effect of adoptive cell therapy along with programmed cell death protein 1 (PD‐1) inhibitor on triple‐negative breast cancer (TNBC). Tumor infiltration lymphocytes (TILs) from TNBC mouse tumor tissues were isolated and expanded, and TILs for adoptive cell therapy (TILs‐ACT) were applied in combination with a PD‐1 inhibitor to the TNBC mouse model. The pre‐ and post‐therapy antitumor efficacy, cytokine secretion, and pathological changes were assessed both in vitro and in vivo. We found that TILs exhibited higher IFN‐γ and TNF‐α secretion than conventional T cells. The TILs‐ACT combined with PD‐1 inhibitor promoted active T‐cell infiltration into the tumor tissue and exerted a strong antitumor effect in an in vivo model. Additionally, the strategy could downregulate the expression of inhibitory marker PD‐1 on TILs. In conclusion, PD‐1 blockade regulated T‐cell exhaustion that synergized with adoptive TIL transfer immunotherapy, leading to eradication of established TNBC tumors. These findings might be useful in developing a feasible and effective therapeutic approach for TNBC. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease‐2019 (COVID‐19) has been associated with cutaneous findings, some being the result of drug hypersensitivity reactions such as maculopapular drug rashes (MDR). The aim of this study was to investigate whether COVID‐19 may impact the development of the MDR. Methods: Blood and skin samples from COVID‐19 patients (based on a positive nasopharyngeal PCR) suffering from MDR (COVID‐MDR), healthy controls, non‐COVID‐19—related patients with drug rash with eosinophilia and systemic symptoms (DRESS), and MDR were analyzed. We utilized imaging mass cytometry (IMC) to characterize the cellular infiltrate in skin biopsies. Furthermore, RNA sequencing transcriptome of skin biopsy samples and high‐throughput multiplexed proteomic profiling of serum were performed. Results: IMC revealed by clustering analyses a more prominent, phenotypically shifted cytotoxic CD8+ T cell population and highly activated monocyte/macrophage (Mo/Mac) clusters in COVID‐MDR. The RNA sequencing transcriptome demonstrated a more robust cytotoxic response in COVID‐MDR skin. However, severe acute respiratory syndrome coronavirus 2 was not detected in skin biopsies at the time point of MDR diagnosis. Serum proteomic profiling of COVID‐MDR patients revealed upregulation of various inflammatory mediators (IL‐4, IL‐5, IL‐6, TNF, and IFN‐γ), eosinophil and Mo/Mac ‐attracting chemokines (MCP‐2, MCP‐3, MCP‐4 and CCL11). Proteomics analyses demonstrated a massive systemic cytokine storm in COVID‐MDR compared with the relatively milder cytokine storm observed in DRESS, while MDR did not exhibit such features. Conclusion: A systemic cytokine storm may promote activation of Mo/Mac and cytotoxic CD8+ T cells in severe COVID‐19 patients, which in turn may impact the development of MDR. [ABSTRACT FROM AUTHOR]

Despite remarkable advances in different types of cancer therapies, an effective therapeutic strategy is still a major and significant challenge. One of the most promising approaches in this regard is immunotherapy, which takes advantage of the patients' immune system; however, the many mechanisms that cancerous cells harbor to extend their survival make it impossible to gain perfect eradication of tumors. The response rate to cancer immunotherapies, especially checkpoint inhibitors and adoptive T cell therapy, substantially differs in various cancer types with the highest rates in advanced melanoma and non‐small cell lung cancer. Indeed, the lack of response in many tumors indicates primary resistance that can originate from either tumor cells (intrinsic) or tumor microenvironment (extrinsic). On the other hand, some tumors show an initial response to immunotherapy followed by relapse in few months (acquired resistance). Understanding the underlying molecular mechanisms of immunotherapy resistance makes it possible to develop effective strategies to overcome this hurdle and boost therapy outcomes. In this review, we take a look at immunotherapy strategies and go through a number of primary and acquired resistance mechanisms. Also, we present various ongoing methods to overcoming resistance and introduce some promising fields to improve the outcome of immunotherapy in patients affected with cancer. [ABSTRACT FROM AUTHOR]

Background: Viral infections are controlled primarily by viral‐specific T cells, raising concern for adequate T‐cell response to clear CMV infection in transplant recipients receiving lymphocyte‐depleting agents (LDA). We examined the rates of CMV viremia and clearance, seroconversion, and CMV‐specific CD8+ T cell (CMV‐Tc) activity with class of induction agent received. Methods: Retrospective review of 45 pediatric renal transplant recipients who received induction with LDA (n = 31) or non‐LDA (NLDA; n = 14) received valganciclovir prophylaxis for 6 months post‐transplant and CMV‐PCR monitoring. CMV‐Tc was measured by intracellular IFNγ flow cytometry, when possible, at baseline, 1 month after CMV viremia (>5 copies/PCR) and serially until CMV‐Tc was positive (≥0.2%). Results: Viremia rates at 1, 2, and 4 years post‐transplant were higher in LDA vs. NLDA (46.3% vs. 7.2%, 64.2% vs. 7.2%, and 64.2% vs. 7.2%, respectively; p =.002). Viremia rates at these time points in seronegative LDA (50.3%, 71.6%, 71.6%) were significantly or near significantly higher than seronegative NLDA (9.1%, 9.1%, 9.1%; p =.004), seropositive‐LDA (22.3%, 22.3%, 22.3%; p =.07), or seropositive NLDA (0%, 0%, 0%; p =.07). Eleven of 17 (64.7%) viremic subjects required valganciclovir dose reduction during the prophylaxis period for leukopenia. All viremic LDA patients developed CMV‐Tc. One viremic NLDA patient did not develop CMV‐Tc. No patients developed CMV disease. Conclusion: CMV seronegative pediatric renal transplant patients receiving LDA are more likely to have valganciclovir prophylaxis dose reduction and develop subclinical CMV viremia; however, all developed CMV‐Tc. Larger prospective studies are needed to further understand the effects of induction agents on CMV‐Tc and CMV‐Tc's role post‐transplant. [ABSTRACT FROM AUTHOR]

In the tumor microenvironment, T cells, B cells, and many other cells play important and distinct roles in anti‐tumor immunotherapy. Although the immune checkpoint blockade and adoptive cell transfer can elicit durable clinical responses, only a few patients benefit from these therapies. Increased understanding of tumor‐infiltrating immune cells can provide novel therapies and drugs that induce a highly specific anti‐tumor immune response to certain groups of patients. Herein, the recent research progress on tumor‐infiltrating B cells and T cells, including CD8+ T cells, CD4+ T cells, and exhausted T cells and their role in anti‐tumor immunity, is summarized. Moreover, several anti‐tumor therapy approaches are discussed based on different immune cells and their prospects for future applications in cancer treatment. [ABSTRACT FROM AUTHOR]

During COVID‐19 infection, reduced function of natural killer (NK) cells can lead to both compromised viral clearance and dysregulation of the immune response. Such dysregulation leads to overproduction of cytokines, a raised neutrophil/lymphocyte ratio and monocytosis. This in turn increases IL‐6 expression, which promotes scar and thrombus formation. Excess IL‐6 also leads to a further reduction in NK function through downregulation of perforin expression, therefore forming a pathogenic auto‐inflammatory feedback loop. The perforin/granzyme system of cytotoxicity is the main mechanism through which NK cells and cytotoxic T lymphocytes eliminate virally infected host cells, as well as being central to their role in regulating immune responses to microbial infection. Here, we present epidemiological evidence suggesting an association between perforin expression and resistance to COVID‐19. In addition, we outline the manner in which a pathogenic auto‐inflammatory feedback loop could operate and the relationship of this loop to genes associated with severe COVID‐19. Such an auto‐inflammatory loop may be amenable to synergistic multimodal therapy. [ABSTRACT FROM AUTHOR]

Summary: Allogeneic immune responses underlie the graft‐versus‐leukaemia effect of stem cell transplantation, but disease relapse occurs in many patients. Minor histocompatibility antigen (mHAg) peptides mediate alloreactive T cell responses and induce graft‐versus‐leukaemia responses when expressed on patient haematopoietic tissue. We vaccinated nine HA‐1‐negative donors against HA‐1 with a 'prime–boost' protocol of either two or three DNA 'priming' vaccinations prior to 'boost' with modified vaccinia Ankara (MVA). HA‐1‐specific CD8+ T cell responses were observed in seven donors with magnitude up to 1·5% of total CD8+ T cell repertoire. HA‐1‐specific responses peaked two weeks post‐MVA challenge and were measurable in most donors after 12 months. HA‐1‐specific T cells demonstrated strong cytotoxic activity and lysed target cells with endogenous HA‐1 protein expression. The pattern of T cell receptor (TCR) usage by HA‐1‐specific T cells revealed strong conservation of T cell receptor beta variable 7‐9 (TRBV7‐9) usage between donors. These findings describe one of the strongest primary peptide‐specific CD8+ T cell responses yet recorded to a DNA–MVA prime–boost regimen and this may reflect the strong immunogenicity of mHAg peptides. Prime–boost vaccination in donors or patients may prove of substantial benefit in boosting graft‐versus‐leukaemia responses. [ABSTRACT FROM AUTHOR]