Out-of-Sequence Signal 3 Paralyzes Primary CD4(+) T-Cell-Dependent Immunity

Effects of combined radiotherapy with immune checkpoint blockade on immunological memory in luminal-like subtype murine bladder cancer model

MIBC is a highly lethal disease, and the patient survival rate has not improved significantly over the last decades. UPPL is a cell line that can be used to recapitulate the luminal-like molecular subtype of bladder cancer and to discover effective treatments to be translated in patients. Here, we investigate the effects of combinational treatments of radiotherapy and immunotherapy in this recently characterized UPPL tumor-bearing mice. We first characterized the baseline tumor microenvironment and the effect of radiation, anti-PD-L1, and combinatorial treatments. Then, the mice were re-challenged with a second tumor (rechallenged tumor) in the contralateral flank of the first tumor to assess the immunological memory. Radiation slowed down the tumor growth. All treatments also decreased the neutrophil population and increased the T cell population. Anti-PD-L1 therapy was not able to synergize with radiation to further delay tumor growth. Furthermore, none of the treatments were able to generate immune memory. The treatments were not sufficient to induce a significant and lasting pool of memory cells. We show here that anti-PD-L1 treatment added to radiotherapy was not enough to achieve T cell-mediated memory in UPPL tumors. Stronger T cell activation signals may be required to enhance radiation efficacy in luminal-like bladder cancer.

Engineering potent chimeric antigen receptor T cells by programming signaling during T-cell activation

Programming cell signaling during T-cell activation represents a simple strategy for improving the potency of therapeutic T-cell products. Stim-R technology (Lyell Immunopharma) is a customizable, degradable synthetic cell biomimetic that emulates physiologic, cell-like presentation of signal molecules to control T-cell activation. A breadth of Stim-R formulations with different anti-CD3/anti-CD28 (αCD3/αCD28) antibody densities and stoichiometries were screened for their effects on multiple metrics of T-cell function. We identified an optimized formulation that produced receptor tyrosine kinase-like orphan receptor 1 (ROR1)-targeted chimeric antigen receptor (CAR) T cells with enhanced persistence and polyfunctionality in vitro, as assessed in repeat-stimulation assays, compared with a benchmark product generated using a conventional T-cell-activating reagent. In transcriptomic analyses, CAR T cells activated with Stim-R technology showed downregulation of exhaustion-associated gene sets and retained a unique subset of stem-like cells with effector-associated gene signatures following repeated exposure to tumor cells. Compared with the benchmark product, CAR T cells activated using the optimized Stim-R technology formulation exhibited higher peak expansion, prolonged persistence, and improved tumor control in a solid tumor xenograft model. Enhancing T-cell products with Stim-R technology during T-cell activation may help improve therapeutic efficacy against solid tumors.

Enhancing pancreatic cancer immunotherapy: Leveraging localized delivery strategies through the use of implantable devices and scaffolds

Pancreatic cancer (PC) remains the predominant type of upper gastrointestinal tract cancer, associated with heightened morbidity and a survival rate below 12%. While immunotherapy has brought about transformative changes in the standards of care for most solid tumors, its application in PC is hindered by the ''cold tumor'' microenvironment, marked by the presence of immunosuppressive cells. Modest response rates in PC are attributed, in part to, the fibrotic stroma that obstructs the delivery of systemic immunotherapy. Furthermore, the occurrence of immune-related adverse events (iRAEs) often necessitates the use of sub-therapeutic doses or treatment discontinuation. In the pursuit of innovative approaches to enhance the effectiveness of immunotherapy for PC, implantable drug delivery devices and scaffolds emerge as promising strategies. These technologies offer the potential for sustained drug delivery directly to the tumor site, overcoming stromal barriers, immunosuppression, T cell exclusion, immunotherapy resistance, optimizing drug dosage, and mitigating systemic toxicity. This review offers a comprehensive exploration of pancreatic ductal adenocarcinoma (PDAC), the most common and aggressive form of PC, accompanied by a critical analysis of the challenges the microenvironment presents to the development of successful combinational immunotherapy approaches. Despite efforts, these approaches have thus far fallen short in enhancing treatment outcomes for PDAC. The review will subsequently delve into the imperative need for refining delivery strategies, providing an examination of past and ongoing studies in the field of localized immunotherapy for PDAC. Addressing these issues will lay the groundwork for the development of effective new therapies, thereby enhancing treatment response, patient survival, and overall quality of life for individuals diagnosed with PDAC.

Immunotherapy targeting tumor-associated antigen in a mouse model of head and neck cancer

BACKGROUND

The identification of epitope peptides from tumor-associated antigens (TAAs) is informative for developing tumor-specific immunotherapy. However, only a few epitopes have been detected in mouse TAAs of head and neck cancer (HNSCC).

METHODS

Novel mouse c-Met-derived T-cell epitopes were predicted by computer-based algorithms. Mouse HNSCC cell line-bearing mice were treated with a c-Met peptide vaccine. The effects of CD8 and/or CD4 T-cell depletion, and vaccine combination with immune checkpoint inhibitors (ICIs) were evaluated. Tumor re-inoculation was performed to assess T-cell memory.

RESULTS

We identified c-Met-derived short and long epitopes that elicited c-Met-reactive antitumor CD8 and/or CD4 T-cell responses. Vaccination using these peptides showed remarkable antitumor responses via T cells in which ICIs were not required. The c-Met peptide-vaccinated mice rejected the re-inoculated tumors.

CONCLUSIONS

We demonstrated that novel c-Met peptide vaccines can induce antitumor T-cell response, and could be a potent immunotherapy in a syngeneic mouse HNSCC model.

Immunotherapy: The Fourth Domain in Oral Cancer Therapeutics

Owing to high global prevalence, incidence and associated mortality, cancer of head and neck particularly oral cancer remains a cardinal domain for research and trials. Immune-modulatory therapies that employ patients own immune system for therapeutic benefits in oral cancer seems promising. The aim of this review is to gauge the potential of immunotherapy as fourth domain of Oral cancer therapeutics. Articles were searched using suitable search terms in MEDLINE and Google Scholar database to include clinical trials, meta-analyses, and research in humans/animals/cell lines published in peer reviewed journals. A total of 97 articles were included in this review. Literature has several studies and trials where different types of immunotherapies has been attempted but it is crucial to identify precise biomarkers of genome based targeted agents and to find parameters to select patients who might benefit from immunotherapy. Also further research is required to estimate predictive value of tumor mutational burden and mutational signatures so as to aid in personalized prediction of oral cancer therapeutic response.

Increased levels of circulating soluble CD226 in multiple sclerosis

BACKGROUND

The glycoprotein CD226 plays a key role in regulating immune cell function. Soluble CD226 (sCD226) is increased in sera of patients with several chronic inflammatory diseases but its levels in neuroinflammatory diseases such as multiple sclerosis (MS) are unknown.

OBJECTIVE

To investigate the presence and functional implications of sCD226 in persons with multiple sclerosis (pwMS) and other neurological diseases.

METHODS

The mechanisms of sCD226 production were first investigated by analyzing CD226 surface expression levels and supernatants of CD3/CD226-coactivated T cells. The role of sCD226 on dendritic cell maturation was evaluated. The concentration of sCD226 in the sera from healthy donors (HD), pwMS, neuromyelitis optica (NMO), and Alzheimer's disease (AD) was measured.

RESULTS

CD3/CD226-costimulation induced CD226 shedding. Addition of sCD226 to dendritic cells during their maturation led to an increased production of the pro-inflammatory cytokine interleukin (IL)-23. We observed a significant increase in sCD226 in sera from pwMS and NMO compared to HD and AD. In MS, levels were increased in both relapsing-remitting multiple sclerosis (RRMS) and secondary-progressive multiple sclerosis (SPMS) compared to clinically isolated syndrome (CIS).

CONCLUSION

Our data suggest that T-cell activation leads to release of sCD226 that could promote inflammation and raises the possibility of using sCD226 as a biomarker for neuroinflammation.

Therapeutic induction of antigen-specific immune tolerance

The development of therapeutic approaches for the induction of robust, long-lasting and antigen-specific immune tolerance remains an important unmet clinical need for the management of autoimmunity, allergy, organ transplantation and gene therapy. Recent breakthroughs in our understanding of immune tolerance mechanisms have opened new research avenues and therapeutic opportunities in this area. Here, we review mechanisms of immune tolerance and novel methods for its therapeutic induction.

Osteomyelitis is associated with increased anti-inflammatory response and immune exhaustion

Introduction

Osteomyelitis (OMS) is a bone infection causing bone pain and severe complications. A balanced immune response is critical to eradicate infection without harming the host, yet pathogens manipulate immunity to establish a chronic infection. Understanding OMS-driven inflammation is essential for disease management, but comprehensive data on immune profiles and immune cell activation during OMS are lacking.

Methods

Using high-dimensional flow cytometry, we investigated the detailed innate and adaptive systemic immune cell populations in OMS and age- and sex-matched controls.

Results

Our study revealed that OMS is associated with increased levels of immune regulatory cells, namely T regulatory cells, B regulatory cells, and T follicular regulatory cells. In addition, the expression of immune activation markers HLA-DR and CD86 was decreased in OMS, while the expression of immune exhaustion markers TIM-3, PD-1, PD-L1, and VISTA was increased. Members of the T follicular helper (Tfh) cell family as well as classical and typical memory B cells were significantly increased in OMS individuals. We also found a strong correlation between memory B cells and Tfh cells.

Discussion

We conclude that OMS skews the host immune system towards the immunomodulatory arm and that the Tfh memory B cell axis is evident in OMS. Therefore, immune-directed therapies may be a promising alternative for eradication and recurrence of infection in OMS, particularly in individuals and areas where antibiotic resistance is a major concern.

Dendritic Cell-Based Immunotherapy: The Importance of Dendritic Cell Migration

Dendritic cells (DCs) are specialized antigen-presenting cells that are crucial for maintaining self-tolerance, initiating immune responses against pathogens, and patrolling body compartments. Despite promising aspects, DC-based immunotherapy faces challenges that include limited availability, immune escape in tumors, immunosuppression in the tumor microenvironment, and the need for effective combination therapies. A further limitation in DC-based immunotherapy is the low population of migratory DC (around 5%-10%) that migrate to lymph nodes (LNs) through afferent lymphatics depending on the LN draining site. By increasing the population of migratory DCs, DC-based immunotherapy could enhance immunotherapeutic effects on target diseases. This paper reviews the importance of DC migration and current research progress in the context of DC-based immunotherapy.

Design and Evaluation of Synthetic Delivery Formulations for Peptide-Based Cancer Vaccines

With the recent advances in neoantigen identification, peptide-based cancer vaccines offer substantial potential in the field of immunotherapy. However, rapid clearance, low immunogenicity, and insufficient antigen-presenting cell (APC) uptake limit the efficacy of peptide-based cancer vaccines. This review explores the barriers hindering vaccine efficiency, highlights recent advancements in synthetic delivery systems, and features strategies for the key delivery steps of lymph node (LN) drainage, APC delivery, cross-presentation strategies, and adjuvant incorporation. This paper also discusses the design of preclinical studies evaluating vaccine efficiency, including vaccine administration routes and murine tumor models.

A comparison of clustering models for inference of T cell receptor antigen specificity

The vast potential sequence diversity of TCRs and their ligands has presented an historic barrier to computational prediction of TCR epitope specificity, a holy grail of quantitative immunology. One common approach is to cluster sequences together, on the assumption that similar receptors bind similar epitopes. Here, we provide the first independent evaluation of widely used clustering algorithms for TCR specificity inference, observing some variability in predictive performance between models, and marked differences in scalability. Despite these differences, we find that different algorithms produce clusters with high degrees of similarity for receptors recognising the same epitope. Our analysis strengthens the case for use of clustering models to identify signals of common specificity from large repertoires, whilst highlighting scope for improvement of complex models over simple comparators.

Posttranscriptional Events Orchestrate Immune Homeostasis of CD8+ T Cells

Maintaining immune homeostasis is instrumental for host health. Immune cells, such as T cells, are instrumental for the eradication of pathogenic bacteria, fungi and viruses. Furthermore, T cells also play a major role in the fight against cancer. Through the formation of immunological memory, a pool of antigen-experienced T cells remains in the body to rapidly protect the host upon reinfection or retransformation. In order to perform their protective function, T cells produce cytolytic molecules, such as granzymes and perforin, and cytokines such as interferon γ and tumor necrosis factor α. Recently, it has become evident that posttranscriptional regulatory events dictate the kinetics and magnitude of cytokine production by murine and human CD8+ T cells. Here, the recent literature regarding the role posttranscriptional regulation plays in maintaining immune homeostasis of antigen-experienced CD8+ T cells is reviewed.

Genetic Diversity and Sequence Conservation of Peptide-Binding Regions of MHC Class I Genes in Pig, Cattle, Chimpanzee, and Human

Comparative analyses of MHC gene diversity and evolution across different species could offer valuable insights into the evolution of MHC genes. Intra- and inter-species sequence diversity and conservation of 12 classical major histocompatibility complex (MHC) class I genes from cattle, chimpanzees, pigs, and humans was analyzed using 20 representative allelic groups for each gene. The combined analysis of paralogous loci for each species revealed that intra-locus amino-acid sequence variations in the peptide-binding region (PBR) of MHC I genes did not differ significantly between species, ranging from 8.44% for SLA to 10.75% for BoLA class I genes. In contrast, intraspecies differences in the non-PBRs of these paralogous genes were more pronounced, varying from 4.59% for SLA to 16.89% for HLA. Interestingly, the Shannon diversity index and rate of nonsynonymous substitutions for PBR were significantly higher in SLA and BoLA than those in Patr and HLA. Analysis of peptide-binding pockets across all analyzed MHC class I genes of the four species indicated that pockets A and E showed the lowest and highest diversity, respectively. The estimated divergence times suggest that primate and artiodactyl MHC class I genes diverged 60.41 Mya, and BoLA and SLA genes diverged 35.34 Mya. These results offer new insights into the conservation and diversity of MHC class I genes in various mammalian species.

The foreign body response: emerging cell types and considerations for targeted therapeutics

The foreign body response (FBR) remains a clinical challenge in the field of biomaterials due to its ability to elicit a chronic and sustained immune response. Modulating the immune response to materials is a modern paradigm in tissue engineering to enhance repair while limiting fibrous encapsulation and implant isolation. Though the classical mediators of the FBR are well-characterized, recent studies highlight that our understanding of the cell types that shape the FBR may be incomplete. In this review, we discuss the emerging role of T cells, stromal-immune cell interactions, and senescent cells in the biomaterial response, particularly to synthetic materials. We emphasize future studies that will deepen the field's understanding of these cell types in the FBR, with the goal of identifying therapeutic targets that will improve implant integration. Finally, we briefly review several considerations that may influence our understanding of the FBR in humans, including rodent models, aging, gut microbiota, and sex differences. A better understanding of the heterogeneous host cell response during the FBR can enable the design and development of immunomodulatory materials that favor healing.

The multi-omics single-cell landscape of sinus mucosa in uncontrolled severe chronic rhinosinusitis with nasal polyps

Uncontrolled severe chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with elevated levels of type 2 inflammatory cytokines and raised immunoglobulin concentrations in nasal polyp tissue. By using single-cell RNA sequencing, transcriptomics, surface proteomics, and T cell and B cell receptor sequencing, we found the predominant cell types in nasal polyps were shifted from epithelial and mesenchymal cells to inflammatory cells compared to nasal mucosa from healthy controls. Broad expansions of CD4 T effector memory cells, CD4 tissue-resident memory T cells, CD8 T effector memory cells and all subtypes of B cells in nasal polyp tissues. The T and B cell receptor repertoires were skewed in NP. This study highlights the deviated immune response and remodeling mechanisms that contribute to the pathogenesis of uncontrolled severe CRSwNP. CLINICAL IMPLICATIONS: We identified differences in the cellular compositions, transcriptomes, proteomes, and deviations in the immune profiles of T cell and B cell receptors as well as alterations in the intercellular communications in uncontrolled severe CRSwNP patients versus healthy controls, which might help to define potential therapeutic targets in the future.

Regulation of human and mouse bystander T cell activation responses by PD-1

Bystander activation of memory T cells occurs via cytokine signaling alone in the absence of T cell receptor (TCR) signaling and provides a means of amplifying T cell effector responses in an antigen-nonspecific manner. While the role of Programmed Cell Death Protein 1 (PD-1) on antigen-specific T cell responses is extensively characterized, its role in bystander T cell responses is less clear. We examined the role of the PD-1 pathway during human and mouse non-antigen-specific memory T cell bystander activation and observed that PD-1+ T cells demonstrated less activation and proliferation than activated PD-1- populations in vitro. Higher activation and proliferative responses were also observed in the PD-1- memory population in both mice and patients with cancer receiving high-dose IL-2, mirroring the in vitro phenotypes. This inhibitory effect of PD-1 could be reversed by PD-1 blockade in vivo or observed using memory T cells from PD-1-/- mice. Interestingly, increased activation through abrogation of PD-1 signaling in bystander-activated T cells also resulted in increased apoptosis due to activation-induced cell death (AICD) and eventual T cell loss in vivo. These results demonstrate that the PD-1/PD-Ligand 1 (PD-L1) pathway inhibited bystander-activated memory T cell responses but also protected cells from AICD.

IL-15 synergizes with CD40 agonist antibodies to induce durable immunity against bladder cancer

CD40 is a central costimulatory receptor implicated in productive antitumor immune responses across multiple cancers, including bladder cancer. Despite strong preclinical rationale, systemic administration of therapeutic agonistic antibodies targeting the CD40 pathway has demonstrated dose-limiting toxicities with minimal clinical activity, emphasizing an important need for optimized CD40-targeted approaches, including rational combination therapy strategies. Here, we describe a role for the endogenous IL-15 pathway in contributing to the therapeutic activity of CD40 agonism in orthotopic bladder tumors, with upregulation of transpresented IL-15/IL-15Rα surface complexes, particularly by cross-presenting conventional type 1 DCs (Dendritic Cells), and associated enrichment of activated CD8 T cells. In bladder cancer patient samples, we identify DCs as the primary source of IL-15, although they lack high levels of IL-15Rα at baseline. Using humanized immunocompetent orthotopic bladder tumor models, we demonstrate the ability to therapeutically augment this interaction through combined treatment with anti-CD40 agonist antibodies and exogenous IL-15, including the fully-human Fc-optimized antibody 2141-V11 currently in clinical development for the treatment of bladder cancer. Collectively, these data reveal an important role for IL-15 in mediating antitumor CD40 agonist responses in bladder cancer and provide key proof-of-concept for combined use of Fc-optimized anti-CD40 agonist antibodies and agents targeting the IL-15 pathway. These data support expansion of ongoing clinical studies evaluating anti-CD40 agonist antibodies and IL-15-based approaches to develop combinations of these promising therapeutics for the treatment of patients with bladder cancer.

Ocular graft-versus-host disease (oGVHD): From A to Z

Allogeneic hematopoietic stem cell transplantation is a definitive therapy for a variety of disorders. One of the complications is acute graft-versus-host disease (aGVHD), which has a high mortality rate. Patients can also develop chronic graft-versus-host disease (cGVHD), a more indolent yet afflicting condition that affects up to 70% of patients. Ocular involvement (oGVHD) is one of the most prevalent presentations of cGVHD and can manifest as dry eye disease, meibomian gland dysfunction, keratitis, and conjunctivitis. Early recognition of ocular involvement using regular clinical assessments as well as robust biomarkers can aid in better management and prevention. Currently, the therapeutic strategies for the management of cGVHD, and oGVHD in particular, have mainly focused on the control of symptoms. There is an unmet need for translating the preclinical and molecular understandings of oGVHD into clinical practice. Herein, we have comprehensively reviewed the pathophysiology, pathologic features, and clinical characteristics of oGVHD and summarized the therapeutic landscape available to combat it. We also discuss the direction of future research regarding a more directed delineation of pathophysiologic underpinnings of oGVHD and the development of preventive interventions.

Cytokine sustained delivery for cancer therapy; special focus on stem cell- and biomaterial- based delivery methods

As immune regulators, cytokines serve critical role as signaling molecules in response to danger, tissue damage, or injury. Importantly, due to their vital role in immunological surveillance, cytokine therapy has become a promising therapeutics for cancer therapy. Cytokines have, however, been used only in certain clinical settings. Two key characteristics of cytokines contribute to this clinical translational challenge: first, they are highly pleiotropic, and second, in healthy physiology, they are typically secreted and act very locally in tissues. Systemic administration of the cytokines can consequently result in serious side effects. Thus, scientists have sought various strategies to circumvent theses hurdles. Recent in vivo reports signify that cytokine delivery platforms can increase their safety and therapeutic efficacy in tumor xenografts. Meanwhile, cytokine delivery using multipotent stem cells, in particular mesenchymal stem/stromal cells (MSCs), and also a diversity of particles and biomaterials has demonstrated greater capability in this regards. Herein, we take a glimpse into the recent advances in cytokine sustained delivery using stem cells and also biomaterials to ease safe and effective treatments of a myriad of human tumors.

Competitive binding of CD226/TIGIT with PVR regulates macrophage polarization and is involved in vascularized skin graft rejection

End-stage organ failure often requires solid organ transplantation. Nevertheless, transplant rejection remains an unresolved issue. The induction of donor-specific tolerance is the ultimate goal in transplantation research. Here, an allograft vascularized skin rejection model using BALB/c-C57/BL6 mice was established to evaluate the regulation of the poliovirus receptor signaling pathway via CD226 knockout (KO) or TIGIT-Fc recombinant protein treatment. In the TIGIT-Fc-treated and CD226KO groups, graft survival time was significantly prolonged, with a Treg cell proportion increase and M2-type macrophage polarization. Donor-reactive recipient T cells became hyporesponsive while responding normally after a third-party antigen challenge. In both groups, serum IL-1β, IL-6, IL-12p70, IL-17A, TNF-α, IFN-γ, and monocyte chemoattractant protein-1 levels decreased, and the IL-10 level increased. In vitro, M2 markers, such as Arg1 and IL-10, were markedly increased by TIGIT-Fc, whereas iNOS, IL-1β, IL-6, IL-12p70, TNF-α, and IFN-γ levels decreased. CD226-Fc had the opposite effect. TIGIT suppressed Th1 and Th17 differentiation by inhibiting macrophage SHP-1 phosphorylation and enhanced ERK1/2-MSK1 phosphorylation and nuclear translocation of CREB. In conclusion, CD226 and TIGIT competitively bind to PVR with activating and inhibitory functions, respectively. Mechanistically, TIGIT promotes IL-10 transcription from macrophages by activating the ERK1/2-MSK1-CREB pathway and enhancing M2-type polarization. CD226/TIGIT-PVR are crucial regulatory molecules of allograft rejection.

The RadScopal Technique as an Immune Adjuvant to Treat Cancer

Since the momentous discovery of X-rays, high-dose radiotherapy (H-XRT) has been a cornerstone for combating cancer. The high-energy electromagnetic waves induce direct damage to tumor-cells’ DNA, thereby halting cell growth and proliferation, and eventually leading to tumor eradication. Furthermore, recent evidence suggests that H-XRT may have immunomodulatory properties which arise from its ability to induce the release of neoantigens, which in turn prime T-cells and contribute to T-cell repertoire diversity. Throughout the years, there have been different treatment modalities introduced as complements to H-XRT that have yielded greater results than monotherapy alone. In this review, we will discuss preclinical and clinical data related to the recently introduced low-dose radiotherapy (L-XRT) modality. We will also explore the justification for combining L-XRT and H-XRT, which became known as the “RadScopal Technique”, as a novel immune adjuvant to treat cancer. In this analysis, we detail and dissect the physiological mechanisms of action of each modality and describe the synergistic amalgamation effect observed on primary and metastatic tumors. Finally, we will explore the impetus for further studies to investigate combinations of the “RadScopal Technique” with various immune-oncology drug candidates.

IL-15 synergizes with CD40 agonist antibodies to induce durable immunity against bladder cancer

CD40 is a central co-stimulatory receptor implicated in the development of productive anti-tumor immune responses across multiple cancers, including bladder cancer. Despite strong preclinical rationale, systemic administration of therapeutic agonistic antibodies targeting the CD40 pathway have demonstrated dose limiting toxicities with minimal clinical activity to date, emphasizing an important need for optimized CD40-targeted approaches, including rational combination therapy strategies. Here, we describe an important role for the endogenous IL-15 pathway in contributing to the therapeutic activity of CD40 agonism in orthotopic bladder tumors, with upregulation of trans-presented IL-15/IL-15Rα surface complexes, particularly by cross-presenting cDC1s, and associated enrichment of activated CD8 T cells within the bladder tumor microenvironment. In bladder cancer patient samples, we identify DCs as the primary source of IL-15, however, they lack high levels of IL-15Rα at baseline. Using humanized immunocompetent orthotopic bladder tumor models, we demonstrate the ability to therapeutically augment this interaction through combined treatment with anti-CD40 agonist antibodies and exogenous IL-15, including the fully-human Fc-optimized antibody 2141-V11 currently in clinical development for the treatment of bladder cancer. Combination therapy enhances the crosstalk between Batf3-dependent cDC1s and CD8 T cells, driving robust primary anti-tumor activity and further stimulating long-term systemic anti-tumor memory responses associated with circulating memory-phenotype T and NK cell populations. Collectively, these data reveal an important role for IL-15 in mediating anti-tumor CD40 agonist responses in bladder cancer and provide key proof-of-concept for combined use of Fc-optimized anti-CD40 agonist antibodies and agents targeting the IL-15 pathway. These data support expansion of ongoing clinical studies evaluating anti-CD40 agonist antibodies and IL-15-based approaches to evaluate combinations of these promising therapeutics for the treatment of patients with bladder cancer.

Once upon a prime: DCs shape cancer immunity

Cytotoxic CD8+ T cells are potent killers of diseased cells, but their functional capacity is often compromised in cancer. The quality of antitumor T cell immunity is determined during T cell priming in the lymph node and further influenced by the local microenvironment of the tumor. Increasing evidence indicates that dendritic cells (DCs) have the capacity to precisely regulate the functional quality of antitumor T cell responses in both locations. In this review, we discuss recent advances in our understanding of how distinct DC-derived signals influence CD8+ T cell differentiation and antitumor functions. Insight into the mechanisms of DC-mediated regulation of antitumor immunity could inspire the development of improved approaches to prevent and reverse T cell dysfunction in cancer.

PRRSV-1 induced lung lesion is associated with an imbalance between costimulatory and coinhibitory immune checkpoints

Porcine reproductive and respiratory syndrome virus (PRRSV) induces a dysregulation on the innate and adaptive immune responses. T-cell activation requires a proper interaction and precise balance between costimulatory and coinhibitory molecules, commonly known as immune checkpoints. This study aims to evaluate the expression of immune checkpoints in lung and tracheobronchial lymph node from piglets infected with two PRRSV-1 strains of different virulence during the early stage of infection. Seventy 4-week-old piglets were grouped into three experimental groups: (i) control, (ii) 3249-infected group (low virulent strain), and (iii) Lena-infected group (virulent strain) and were euthanized at 1, 3, 6, 8, and 13 days post-infection (dpi). Lung and tracheobronchial lymph node were collected to evaluate histopathological findings, PRRSV viral load and mRNA expression of costimulatory (CD28, CD226, TNFRSF9, SELL, ICOS, and CD40) and coinhibitory (CTLA4, TIGIT, PD1/PDL1, TIM3, LAG3, and IDO1) molecules through RT-qPCR. Our findings highlight a mild increase of costimulatory molecules together with an earlier and stronger up-regulation of coinhibitory molecules in both organs from PRRSV-1-infected animals, especially in the lung from virulent Lena-infected animals. The simultaneous expression of coinhibitory immune checkpoints could work in synergy to control and limit the inflammation-induced tissue damage. Further studies should be addressed to determine the role of these molecules in later stages of PRRSV infection.

CAR T cell therapy becomes CHIC: "cytokine help intensified CAR" T cells

Chimeric antigen receptors (CARs) in the canonical "second generation" format provide two signals for inducing T cell effector functions; the primary "signal-1" is provided through the TCR CD3ζ chain and the "signal-2" through a linked costimulatory domain to augment activation. While therapy with second generation CAR T cells can induce remissions of leukemia/lymphoma in a spectacular fashion, CAR T cell persistence is frequently limited which is thought to be due to timely limited activation. Following the "three-signal" dogma for inducing a sustained T cell response, cytokines were supplemented to provide "signal-3" to CAR T cells. Recent progress in the understanding of structural biology and receptor signaling has allowed to engineer cytokines for more selective, fine-tuned stimulation of CAR T cells including an artificial autocrine loop of a transgenic cytokine, a cytokine anchored to the CAR T cell membrane or inserted into the extracellular CAR domain, and a cytokine receptor signaling moiety co-expressed with the CAR or inserted into the CAR endodomain. Here we discuss the recent strategies and options for engineering such "cytokine help intensified CAR" (CHIC) T cells for use in adoptive cell therapy.

The T Cell Journey: A Tour de Force

T cells act as the puppeteers in the adaptive immune response, and their dysfunction leads to the initiation and progression of pathological conditions. During their lifetime, T cells experience myriad forces that modulate their effector functions. These forces are imposed by interacting cells, surrounding tissues, and shear forces from fluid movement. In this review, a journey with T cells is made, from their development to their unique characteristics, including the early studies that uncovered their mechanosensitivity. Then the studies pertaining to the responses of T cell activation to changes in antigen-presenting cells' physical properties, to their immediate surrounding extracellular matrix microenvironment, and flow conditions are highlighted. In addition, it is explored how pathological conditions like the tumor microenvironment can hinder T cells and allow cancer cells to escape elimination.

Effector Th1 cells under PD-1 and CTLA-4 checkpoint blockade abrogate the upregulation of multiple inhibitory receptors and by-pass exhaustion

Immune checkpoint inhibitor (ICI) immunotherapy relies on the restoration of T-cell functions. The ICI receptors are not only found on exhausted T cells but also upregulated upon activation and reach high levels on effector T cells. In an ex vivo model, this study explored the consequences of PD-1 and cytotoxic T-lymphocyte antigen (CTLA-4) blockade applied during specific time frames of T-cell stimulation that coincide with distinct functional phases in type 1 helper T (Th1) cells. When applied at an early stimulation stage, the checkpoint blockade interfered with the upregulation of multiple inhibitory receptors such as PD-1, LAG3, TIM-3 and CTLA-4. Moreover, extension of the blockade period restricted the hyporesponsiveness in T cells. Alternatively, a short-term ICI treatment was advantageous when applied at late time frames of Th1 cell stimulation. Here, a transition phase from effector to exhausted state, which coincided with the late time frames of Th1 stimulation, was clearly determined together with the transcriptomics data demonstrating the initiation of significant alterations in metabolic pathways, genetic information processes, effector and exhaustion specific pathways. Applied in this transition phase, PD-1 and/or CTLA-4 blockade downregulated the inhibitory receptors which were already present on the effector Th1 cells, potentially through endocytic pathways. Therefore, the efficacy of ICI therapy was modulated by the functional status of T cells and can be improved by modifying the timing and duration of PD-1 and CTLA-4 blockade. In conclusion, the ICI therapy not only supports the reactivation of T cells but can also constrain de novo exhaustion.

Roles of TGF-β in cancer hallmarks and emerging onco-therapeutic design

Transforming growth factor-beta (TGF-β) is a double-edged sword in cancer treatment because of its pivotal yet complex and roles played during cancer initiation/development. Current anti-cancer strategies involving TGF-β largely view TGF-β as an onco-therapeutic target that not only substantially hinders its full utilisation for cancer control, but also considerably restricts innovations in this field. Thereby, how to take advantages of therapeutically favourable properties of TGF-β for cancer management represents an interesting and less investigated problem. Here, by categorising cancer hallmarks into four critical transition events and one enabling characteristic controlling cancer initiation and progression, and delineating TGF-β complexities according to these cancer traits, we identify the suppressive role of TGF-β in tumour initiation and early-stage progression and its promotive functionalities in cancer metastasis as well as other cancer hallmarks. We also propose the feasibility and possible scenarios of combining cold atmospheric plasma (CAP) with onco-therapeutics utilising TGF-β for cancer control given the intrinsic properties of CAP against cancer hallmarks.

Circulating monocytes associated with anti-PD-1 resistance in human biliary cancer induce T cell paralysis

Suppressive myeloid cells can contribute to immunotherapy resistance, but their role in response to checkpoint inhibition (CPI) in anti-PD-1 refractory cancers, such as biliary tract cancer (BTC), remains elusive. We use multiplexed single-cell transcriptomic and epitope sequencing to profile greater than 200,000 peripheral blood mononuclear cells from advanced BTC patients (n = 9) and matched healthy donors (n = 8). Following anti-PD-1 treatment, CD14+ monocytes expressing high levels of immunosuppressive cytokines and chemotactic molecules (CD14CTX) increase in the circulation of patients with BTC tumors that are CPI resistant. CD14CTX can directly suppress CD4+ T cells and induce SOCS3 expression in CD4+ T cells, rendering them functionally unresponsive. The CD14CTX gene signature associates with worse survival in patients with BTC as well as in other anti-PD-1 refractory cancers. These results demonstrate that monocytes arising after anti-PD-1 treatment can induce T cell paralysis as a distinct mode of tumor-mediated immunosuppression leading to CPI resistance.

Mapping autophagosome contents identifies interleukin-7 receptor-α as a key cargo modulating CD4+ T cell proliferation

CD4+ T cells are pivotal cells playing roles in the orchestration of humoral and cytotoxic immune responses. It is known that CD4+ T cell proliferation relies on autophagy, but identification of the autophagosomal cargo involved is missing. Here we create a transgenic mouse model, to enable direct mapping of the proteinaceous content of autophagosomes in primary cells by LC3 proximity labelling. Interleukin-7 receptor-α, a cytokine receptor mostly found in naïve and memory T cells, is reproducibly detected in autophagosomes of activated CD4+ T cells. Consistently, CD4+ T cells lacking autophagy show increased interleukin-7 receptor-α surface expression, while no defect in internalisation is observed. Mechanistically, excessive surface interleukin-7 receptor-α sequestrates the common gamma chain, impairing the interleukin-2 receptor assembly and downstream signalling crucial for T cell proliferation. This study shows that key autophagy substrates can be reliably identified in this mouse model and help mechanistically unravel autophagy's contribution to healthy physiology and disease.

Abnormalities of T cells in systemic lupus erythematosus: new insights in pathogenesis and therapeutic strategies

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by loss of immune tolerance and sustained production of autoantibodies. Multiple and profound T cell abnormalities in SLE are intertwined with disease expression. Both numerical and functional disturbances have been reported in main CD4⁺ T helper cell subsets including Th1, Th2, Th17, regulatory, and follicular helper cells. SLE CD4⁺ T cells are known to provide help to B cells, produce excessive IL-17 but insufficient IL-2, and infiltrate tissues. In the absence of sufficient amounts of IL-2, regulatory T cells, do not function properly to constrain inflammation. A complicated series of early signaling defects and aberrant activation of kinases and phosphatases result in complex cell phenotypes by altering the metabolic profile and the epigenetic landscape. All main metabolic pathways including glycolysis, glutaminolysis and oxidative phosphorylation are altered in T cells from lupus prone mice and patients with SLE. SLE CD8⁺ cytotoxic T cells display reduced cytolytic activity which accounts for higher rates of infection and the sustenance of autoimmunity. Further, CD8⁺ T cells in the context of rheumatic diseases lose the expression of CD8, acquire IL-17⁺CD4^-CD8^- double negative T (DNT) cell phenotype and infiltrate tissues. Herein we present an update on these T cell abnormalities along with underlying mechanisms and discuss how these advances can be exploited therapeutically. Novel strategies to correct these aberrations in T cells show promise for SLE treatment.

IL15 and Anti-PD-1 Augment the Efficacy of Agonistic Intratumoral Anti-CD40 in a Mouse Model with Multiple TRAMP-C2 Tumors

PURPOSE

IL15 promotes activation and maintenance of natural killer (NK) and CD8+ T effector memory cells making it a potential immunotherapeutic agent for the treatment of cancer. However, monotherapy with IL15 was ineffective in patients with cancer, indicating that it would have to be used in combination with other anticancer agents. The administration of high doses of common gamma chain cytokines, such as IL15, is associated with the generation of "helpless" antigen-nonspecific CD8 T cells. The generation of the tumor-specific cytotoxic T cells can be mediated by CD40 signaling via agonistic anti-CD40 antibodies. Nevertheless, parenteral administration of anti-CD40 antibodies is associated with unacceptable side effects, such as thrombocytopenia and hepatic toxicity, which can be avoided by intratumoral administration.

EXPERIMENTAL DESIGN

We investigated the combination of IL15 with an intratumoral anti-CD40 monoclonal antibody (mAb) in a dual tumor TRAMP-C2 murine prostate cancer model and expanded the regimen to include an anti-PD-1 mAb.

RESULTS

Here we demonstrated that anti-CD40 given intratumorally not only showed significant antitumor activity in treated tumors, but also noninjected contralateral tumors, indicative of abscopal efficacy. The combination of IL15 with intratumoral anti-CD40 showed an additive immune response with an increase in the number of tumor-specific tetramer-positive CD8 T cells. Furthermore, the addition of anti-PD-1 further improved efficacy mediated by the anti-CD40/IL15 combination.

CONCLUSIONS

These studies support the initiation of a clinical trial in patients with cancer using IL15 in association with the checkpoint inhibitor, anti-PD-1, and intratumoral optimized anti-CD40.

Activation pathways that drive CD4+ T cells to break tolerance in autoimmune diseases. Immunol Rev 2022;307:161-190. [PMID: 35142369 PMCID: PMC9255211 DOI: 10.1111/imr.13071]

Autoimmune diseases are characterized by dysfunctional immune systems that misrecognize self as non-self and cause tissue destruction. Several cell types have been implicated in triggering and sustaining disease. Due to a strong association of major histocompatibility complex II (MHC-II) proteins with various autoimmune diseases, CD4+ T lymphocytes have been thoroughly investigated for their roles in dictating disease course. CD4+ T cell activation is a coordinated process that requires three distinct signals: Signal 1, which is mediated by antigen recognition on MHC-II molecules; Signal 2, which boosts signal 1 in a costimulatory manner; and Signal 3, which helps to differentiate the activated cells into functionally relevant subsets. These signals are disrupted during autoimmunity and prompt CD4+ T cells to break tolerance. Herein, we review our current understanding of how each of the three signals plays a role in three different autoimmune diseases and highlight the genetic polymorphisms that predispose individuals to autoimmunity. We also discuss the drawbacks of existing therapies and how they can be addressed to achieve lasting tolerance in patients.

Dendritic cell-based cancer immunotherapy in the era of immune checkpoint inhibitors: From bench to bedside

Dendritic cells (DCs) can present tumoral antigens to T-cells and stimulate T-cell-mediated anti-tumoral immune responses. In addition to uptaking, processing, and presenting tumoral antigens to T-cells, co-stimulatory signals have to be established between DCs with T-cells to develop anti-tumoral immune responses. However, most of the tumor-infiltrated immune cells are immunosuppressive in the tumor microenvironment (TME), paving the way for immune evasion of tumor cells. This immunosuppressive TME has also been implicated in suppressing the DC-mediated anti-tumoral immune responses, as well. Various factors, i.e., immunoregulatory cells, metabolic factors, tumor-derived immunosuppressive factors, and inhibitory immune checkpoint molecules, have been implicated in developing the immunosuppressive TME. Herein, we aimed to review the biology of DCs in developing T-cell-mediated anti-tumoral immune responses, the significance of immunoregulatory cells in the TME, metabolic barriers contributing to DCs dysfunction in the TME, tumor-derived immunosuppressive factors, and inhibitory immune checkpoint molecules in DC-based cell therapy outcomes. With reviewing the ongoing clinical trials, we also proposed a novel therapeutic strategy to increase the efficacy of DC-based cell therapy. Indeed, the combination of DC-based cell therapy with monoclonal antibodies against novel immune checkpoint molecules can be a promising strategy to increase the response rate of patients with cancers.

Development of an Immortalized Porcine Fibroblast Cell Panel With Different Swine Leukocyte Antigen Genotypes

Immortalized cell lines are valuable resources to expand the molecular characterization of major histocompatibility complex genes and their presented antigens. We generated a panel of immortalized cell lines by transfecting human telomerase reverse transcriptase (hTERT) into primary fibroblast cells prepared from ear, fetal, and lung tissues of 10 pigs from five breeds and successfully cultured them for 30-45 passages. The cell growth characteristic of the immortalized fibroblasts was similar to that of primary fibroblast, which was unable to form colonies on soft agar. The genotypes of major swine leukocyte antigen (SLA) genes, including three classical class I (SLA-1, -2, and -3) and three class II genes (DQB1, DRB1, and DQA), were determined using high-resolution typing. A total of 58 alleles, including a novel allele for SLA-2, were identified. Each cell line was unique. A cell line derived from a National Institutes of Health miniature pig was homozygous across the six major SLA genes. The expression levels of SLA classical class I genes varied among the cell lines and were slightly upregulated in the immortalized compared to the primary cells based on semiquantitative reverse transcription polymerase chain reaction. The immortalized porcine fibroblast cell lines with diverse SLA haplotypes that were developed in this study have potential to be applied in studies regarding the molecular characteristics and genetic structure of SLA genes and epitope-major histocompatibility complex interactions in pigs.

The Tyrosine Kinase Tec Regulates Effector Th17 Differentiation, Pathogenicity, and Plasticity in T-Cell-Driven Intestinal Inflammation

T helper (Th) 17 cells are not only key in controlling infections mediated by extracellular bacteria and fungi but are also triggering autoimmune responses. Th17 cells comprise heterogeneous subsets, some with pathogenic functions. They can cease to secrete their hallmark cytokine IL-17A and even convert to other T helper lineages, a process known as transdifferentiation relying on plasticity. Both pathogenicity and plasticity are tightly linked to IL-23 signaling. Here, we show that the protein tyrosine kinase Tec is highly induced in Th17 cells. Th17 differentiation was enhanced at low interleukin-6 (IL-6) concentrations in absence of Tec, which correlates with increased STAT3 phosphorylation and higher Il23r expression. Therefore, we uncovered a function for Tec in the IL-6 sensing via STAT3 by CD4⁺ T cells, defining Tec as a fine-tuning negative regulator of Th17 differentiation. Subsequently, by using the IL-17A fate mapping mouse combined with in vivo adoptive transfer models, we demonstrated that Tec not only restrained effector Th17 differentiation but also pathogenicity and plasticity in a T-cell intrinsic manner. Our data further suggest that Tec regulates inflammatory Th17-driven immune responses directly impacting disease severity in a T-cell-driven colitis model. Notably, consistent with the in vitro findings, elevated levels of the IL-23 receptor (IL-23R) were observed on intestinal pre- and postconversion Th17 cells isolated from diseased Tec^-/- mice subjected to adoptive transfer colitis, highlighting a fundamental role of Tec in restraining IL-23R expression, likely via the IL-6-STAT3 signaling axis. Taken together, these findings identify Tec as a negative regulator of Th17 differentiation, pathogenicity, and plasticity, contributing to the mechanisms which help T cells to orchestrate optimal immune protection and to restrain immunopathology.

In vivo genome-wide CRISPR screens identify SOCS1 as intrinsic checkpoint of CD4+ TH1 cell response

[Figure: see text].

T cell activation niches-Optimizing T cell effector function in inflamed and infected tissues

Successful immunity to infection, malignancy, and tissue damage requires the coordinated recruitment of numerous immune cell subsets to target tissues. Once within the target tissue, effector T cells rely on local chemotactic cues and structural cues from the tissue matrix to navigate the tissue, interact with antigen-presenting cells, and release effector cytokines. This highly dynamic process has been "caught on camera" in situ by intravital multiphoton imaging. Initial studies revealed a surprising randomness to the pattern of T cell migration through inflamed tissues, behavior thought to facilitate chance encounters with rare antigen-bearing cells. Subsequent tissue-wide visualization has uncovered a high degree of spatial preference when it comes to T cell activation. Here, we discuss the basic tenants of a successful effector T cell activation niche, taking cues from the dynamics of Tfh positioning in the lymph node germinal center. In peripheral tissues, steady-state microanatomical organization may direct the location of "pop-up" de novo activation niches, often observed as perivascular clusters, that support early effector T cell activation. These perivascular activation niches appear to be regulated by site-specific chemokines that coordinate the recruitment of dendritic cells and other innate cells for local T cell activation, survival, and optimized effector function.

Mechanisms of Immune Checkpoint Inhibitor-Mediated Colitis

Immune checkpoint inhibitors (ICIs) have provided tremendous clinical benefit in several cancer types. However, systemic activation of the immune system also leads to several immune-related adverse events. Of these, ICI-mediated colitis (IMC) occurs frequently and is the one with the highest absolute fatality. To improve current treatment strategies, it is important to understand the cellular mechanisms that induce this form of colitis. In this review, we discuss important pathways that are altered in IMC in mouse models and in human colon biopsy samples. This reveals a complex interplay between several types of immune cells and the gut microbiome. In addition to a mechanistic understanding, patients at risk should be identifiable before ICI therapy. Here we propose to focus on T-cell subsets that interact with bacteria after inducing epithelial damage. Especially, intestinal resident immune cells are of interest. This may lead to a better understanding of IMC and provides opportunities for prevention and management.

Implications of a 'Third Signal' in NK Cells

Innate and adaptive immune systems are evolutionarily divergent. Primary signaling in T and B cells depends on somatically rearranged clonotypic receptors. In contrast, NK cells use germline-encoded non-clonotypic receptors such as NCRs, NKG2D, and Ly49H. Proliferation and effector functions of T and B cells are dictated by unique peptide epitopes presented on MHC or soluble humoral antigens. However, in NK cells, the primary signals are mediated by self or viral proteins. Secondary signaling mediated by various cytokines is involved in metabolic reprogramming, proliferation, terminal maturation, or memory formation in both innate and adaptive lymphocytes. The family of common gamma (γc) cytokine receptors, including IL-2Rα/β/γ, IL-7Rα/γ, IL-15Rα/β/γ, and IL-21Rα/γ are the prime examples of these secondary signals. A distinct set of cytokine receptors mediate a ‘third’ set of signaling. These include IL-12Rβ1/β2, IL-18Rα/β, IL-23R, IL-27R (WSX-1/gp130), IL-35R (IL-12Rβ2/gp130), and IL-39R (IL-23Rα/gp130) that can prime, activate, and mediate effector functions in lymphocytes. The existence of the ‘third’ signal is known in both innate and adaptive lymphocytes. However, the necessity, context, and functional relevance of this ‘third signal’ in NK cells are elusive. Here, we define the current paradigm of the ‘third’ signal in NK cells and enumerate its clinical implications.

Aging-dependent mitochondrial dysfunction mediated by ceramide signaling inhibits antitumor T cell response

We lack a mechanistic understanding of aging-mediated changes in mitochondrial bioenergetics and lipid metabolism that affect T cell function. The bioactive sphingolipid ceramide, induced by aging stress, mediates mitophagy and cell death; however, the aging-related roles of ceramide metabolism in regulating T cell function remain unknown. Here, we show that activated T cells isolated from aging mice have elevated C14/C16 ceramide accumulation in mitochondria, generated by ceramide synthase 6, leading to mitophagy/mitochondrial dysfunction. Mechanistically, aging-dependent mitochondrial ceramide inhibits protein kinase A, leading to mitophagy in activated T cells. This aging/ceramide-dependent mitophagy attenuates the antitumor functions of T cells in vitro and in vivo. Also, inhibition of ceramide metabolism or PKA activation by genetic and pharmacologic means prevents mitophagy and restores the central memory phenotype in aging T cells. Thus, these studies help explain the mechanisms behind aging-related dysregulation of T cells' antitumor activity, which can be restored by inhibiting ceramide-dependent mitophagy.

miRNAs and lncRNAs as Novel Therapeutic Targets to Improve Cancer Immunotherapy

Simple Summary

Cancer onset and progression are promoted by high deregulation of the immune system. Recently, major advances in molecular and clinical cancer immunology have been achieved, offering new agents for the treatment of common tumors, often with astonishing benefits in terms of prolonged survival and even cure. Unfortunately, most tumors are still resistant to current immune therapy approaches, and basic knowledge of the resistance mechanisms is eagerly awaited. We focused our attention on noncoding RNAs, a class of RNA that regulates many biological processes by targeting selectively crucial molecular pathways and that, recently, had their role in cancer cell immune escape and modulation of the tumor microenvironment identified, suggesting their function as promising immunotherapeutic targets. In this scenario, we point out that noncoding RNAs are progressively emerging as immunoregulators, and we depict the current information on the complex network involving the immune system and noncoding RNAs and the promising therapeutic options under investigation. Novel opportunities are emerging from noncoding-RNAs for the treatment of immune-refractory tumors.

Abstract

Immunotherapy is presently one of the most promising areas of investigation and development for the treatment of cancer. While immune checkpoint-blocking monoclonal antibodies and chimeric antigen receptor (CAR) T-cell-based therapy have recently provided in some cases valuable therapeutic options, the goal of cure has not yet been achieved for most malignancies and more efforts are urgently needed. Noncoding RNAs (ncRNA), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), regulate several biological processes via selective targeting of crucial molecular signaling pathways. Recently, the key roles of miRNA and lncRNAs as regulators of the immune-response in cancer have progressively emerged, since they may act (i) by shaping the intrinsic tumor cell and microenvironment (TME) properties; (ii) by regulating angiogenesis, immune-escape, epithelial-to-mesenchymal transition, invasion, and drug resistance; and (iii) by acting as potential biomarkers for prognostic assessment and prediction of response to immunotherapy. In this review, we provide an overview on the role of ncRNAs in modulating the immune response and the TME. We discuss the potential use of ncRNAs as potential biomarkers or as targets for development or clinical translation of new therapeutics. Finally, we discuss the potential combinatory approaches based on ncRNA targeting agents and tumor immune-checkpoint inhibitor antibodies or CAR-T for the experimental treatment of human cancer.

mRNA-encoded, constitutively active STINGV155M is a potent genetic adjuvant of antigen-specific CD8+ T cell response

mRNA vaccines induce potent immune responses in preclinical models and clinical studies. Adjuvants are used to stimulate specific components of the immune system to increase immunogenicity of vaccines. We utilized a constitutively active mutation (V155M) of the stimulator of interferon (IFN) genes (STING), which had been described in a patient with STING-associated vasculopathy with onset in infancy (SAVI), to act as a genetic adjuvant for use with our lipid nanoparticle (LNP)-encapsulated mRNA vaccines. mRNA-encoded constitutively active STING^V155M was most effective at maximizing CD8⁺ T cell responses at an antigen/adjuvant mass ratio of 5:1. STING^V155M appears to enhance development of antigen-specific T cells by activating type I IFN responses via the nuclear factor κB (NF-κB) and IFN-stimulated response element (ISRE) pathways. mRNA-encoded STING^V155M increased the efficacy of mRNA vaccines encoding the E6 and E7 oncoproteins of human papillomavirus (HPV), leading to reduced HPV⁺ TC-1 tumor growth and prolonged survival in vaccinated mice. This proof-of-concept study demonstrated the utility of an mRNA-encoded genetic adjuvant.

CD4+ T Cells: Multitasking Cells in the Duty of Cancer Immunotherapy

Cancer immunotherapy activates the immune system to specifically target malignant cells. Research has often focused on CD8+ cytotoxic T cells, as those have the capacity to eliminate tumor cells after specific recognition upon TCR-MHC class I interaction. However, CD4+ T cells have gained attention in the field, as they are not only essential to promote help to CD8+ T cells, but are also able to kill tumor cells directly (via MHC-class II dependent recognition) or indirectly (e.g., via the activation of other immune cells like macrophages). Therefore, immunotherapy approaches have shifted from only stimulating CD8+ T cells to targeting and assessing both, CD4+ and CD8+ T cell subsets. Here, we discuss the various subsets of CD4+ T cells, their plasticity and functionality, their relevance in the antitumor immune response in patients affected by cancer, and their ever-growing role in therapeutic approaches for human cancer.

PD-1 Blockade Reverses Obesity-Mediated T Cell Priming Impairment

Despite obesity reaching pandemic proportions, its impact on antigen-specific T cell responses is still unclear. We have recently demonstrated that obesity results in increased expression of PD-1 on T cells, and checkpoint blockade targeting PD-1/PD-L1 surprisingly resulted in greater clinical efficacy in cancer therapy. Adverse events associated with this therapy center around autoimmune reactions. In this study, we examined the impact of obesity on T cell priming and on autoimmune pathogenesis using the mouse model experimental autoimmune encephalomyelitis (EAE), which is mediated by autoreactive myelin-specific T cells generated after immunization. We observed that diet-induced obese (DIO) mice had a markedly delayed EAE onset and developed milder clinical symptoms compared to mice on control diet (CD). This delay was associated with impaired generation of myelin-specific T cell numbers and concurrently correlated with increased PD-L1 upregulation on antigen-presenting cells in secondary lymphoid organs. PD-1 blockade during the priming stage of EAE restored disease onset and severity and increased numbers of pathogenic CD4+ T cells in the central nervous system (CNS) of DIO mice to similar levels to those of CD mice. Administration of anti-PD-1 after onset of clinical symptoms did not increase EAE pathogenesis demonstrating that initial priming is the critical juncture affected by obesity. These findings demonstrate that obesity impairs antigen-specific T cell priming, but this can be reversed with PD-1 blockade. Our results further suggest that PD-1 blockade may increase the risk of autoimmune toxicities, particularly in obesity.

Analysis of tumor-infiltrating NK and T cells highlights IL-15 stimulation and TIGIT blockade as a combination immunotherapy strategy for soft tissue sarcomas

Purpose

Given the unmet need for novel immunotherapy in soft tissue sarcoma (STS), we sought to characterize the phenotype and function of intratumoral natural killer (NK) and T cells to identify novel strategies to augment tumor-infiltrating lymphocyte (TIL) function.

Experimental design

Using prospectively collected specimens from dogs and humans with sarcomas, archived specimens, and The Cancer Genome Atlas (TCGA) data, we evaluated blood and tumor NK and T cell phenotype and function and correlated those with outcome. We then assessed the effects of interleukin 15 (IL-15) stimulation on both NK and T cell activation and TIGIT upregulation. Finally, we evaluated cytotoxic effects of IL-15 combined with TIGIT blockade using a novel anti-TIGIT antibody.

Results

TILs were strongly associated with survival outcome in both archived tissue and TCGA, but higher TIL content was also associated with higher TIGIT expression. Compared with blood, intratumoral NK and T cells showed significantly higher expression of both activation and exhaustion markers, in particular TIGIT. Ex vivo stimulation of blood and tumor NK and T cells from patients with STS with IL-15 further increased both activation and exhaustion markers, including TIGIT. Dogs with metastatic osteosarcoma receiving inhaled IL-15 also exhibited upregulation of activation markers and TIGIT. Ex vivo, combined IL-15 and TIGIT blockade using STS blood and tumor specimens significantly increased cytotoxicity against STS targets.

Conclusion

Intratumoral NK and T cells are prognostic in STS, but their activation is marked by significant upregulation of TIGIT. Our data suggest that combined IL-15 and TIGIT blockade may be a promising clinical strategy in STS.

Cytokines and costimulation in acute graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (alloSCT) is an important curative therapy for high-risk hematological malignancies, but the development of severe and/or steroid-refractory acute graft-versus-host disease (aGVHD) remains a significant limitation to optimal outcomes. New approaches to prevent and treat aGVHD remain an unmet need that can be best addressed by understanding the complex disease pathophysiology. It is now clear that chemoradiotherapy used prior to alloSCT induces the release of endogenous alarmins (eg, HMGB-1, ATP, IL-1α, IL-33) from recipient tissue. Exogenous pathogen-derived molecules (eg, lipopolysaccharide, nucleic acids) also translocate from the gastrointestinal tract lumen. Together, these danger signals activate antigen-presenting cells (APCs) to efficiently present alloantigen to donor T cells while releasing cytokines (eg, interleukin-12 [IL-12], IL-23, IL-6, IL-27, IL-10, transforming growth factor-β) that expand and differentiate both pathogenic and regulatory donor T cells. Concurrent costimulatory signals at the APC-T-cell interface (eg, CD80/CD86-CD28, CD40-CD40L, OX40L-OX40, CD155/CD112-DNAM-1) and subsequent coinhibitory signals (eg, CD80/CD86-CTLA4, PDL1/2-PD1, CD155/CD112-TIGIT) are critical to the acquisition of effector T-cell function and ensuing secretion of pathogenic cytokines (eg, IL-17, interferon-γ, tissue necrosis factor, granulocyte-macrophage colony-stimulating factor) and cytolytic degranulation pathway effectors (eg, perforin/granzyme). This review focuses on the combination of cytokine and costimulatory networks at the T-cell surface that culminates in effector function and subsequent aGVHD in target tissue. Together, these pathways now represent robust and clinically tractable targets for preventing the initiation of deleterious immunity after alloSCT.

Interleukin-15 (dys)regulation of lymphoid homeostasis: Implications for therapy of autoimmunity and cancer

IL-15 supports NK, NK-T, γδ, ILC1, and memory CD8 T cell function, and dysregulated IL-15 is associated with many autoimmune diseases. Striking IL-15–driven increases in NK and CD8 T cells in patients highlight the potential for combination therapy of cancers.

IL-15, a pleiotropic cytokine, stimulates generation of NK, NK-T, γδ, ILC1, and memory CD8 T cells. IL-15 disorders play pathogenetic roles in organ-specific autoimmune diseases including celiac disease. Diverse approaches are developed to block IL-15 action. IL-15 administered to patients with malignancy yielded dramatic increases in NK numbers and modest increases in CD8 T cells. Due to immunological checkpoints, to achieve major cancer therapeutic efficacy, IL-15 will be used in combination therapy, and combination trials with checkpoint inhibitors, with anti-CD40 to yield tumor-specific CD8 T cells, and with anticancer monoclonal antibodies to increase ADCC and antitumor efficacy, have been initiated.

ASGR1 and Its Enigmatic Relative, CLEC10A

The large family of C-type lectin (CLEC) receptors comprises carbohydrate-binding proteins that require Ca²⁺ to bind a ligand. The prototypic receptor is the asialoglycoprotein receptor-1 (ASGR1, CLEC4H1) that is expressed primarily by hepatocytes. The early work on ASGR1, which is highly specific for N-acetylgalactosamine (GalNAc), established the foundation for understanding the overall function of CLEC receptors. Cells of the immune system generally express more than one CLEC receptor that serve diverse functions such as pathogen-recognition, initiation of cellular signaling, cellular adhesion, glycoprotein turnover, inflammation and immune responses. The receptor CLEC10A (C-type lectin domain family 10 member A, CD301; also called the macrophage galactose-type lectin, MGL) contains a carbohydrate-recognition domain (CRD) that is homologous to the CRD of ASGR1, and thus, is also specific for GalNAc. CLEC10A is most highly expressed on immature DCs, monocyte-derived DCs, and alternatively activated macrophages (subtype M2a) as well as oocytes and progenitor cells at several stages of embryonic development. This receptor is involved in initiation of T_H1, T_H2, and T_H17 immune responses and induction of tolerance in naïve T cells. Ligand-mediated endocytosis of CLEC receptors initiates a Ca²⁺ signal that interestingly has different outcomes depending on ligand properties, concentration, and frequency of administration. This review summarizes studies that have been carried out on these receptors.

Costimulation Induces CD4 T Cell Antitumor Immunity via an Innate-like Mechanism

Chronic exposure to tumor-associated antigens inactivates cognate T cells, restricting the repertoire of tumor-specific effector T cells. This problem was studied here by transferring TCR transgenic CD4 T cells into recipient mice that constitutively express a cognate self-antigen linked to MHC II on CD11c-bearing cells. Immunotherapeutic agonists to CD134 plus CD137, "dual costimulation," induces specific CD4 T cell expansion and expression of the receptor for the Th2-associated IL-1 family cytokine IL-33. Rather than producing IL-4, however, they express the tumoricidal Th1 cytokine IFNγ when stimulated with IL-33 or IL-36 (a related IL-1 family member) plus IL-12 or IL-2. IL-36, which is induced within B16-F10 melanomas by dual costimulation, reduces tumor growth when injected intratumorally as a monotherapy and boosts the efficacy of tumor-nonspecific dual costimulated CD4 T cells. Dual costimulation thus enables chronic antigen-exposed CD4 T cells, regardless of tumor specificity, to elaborate tumoricidal function in response to tumor-associated cytokines.