Late-rising CD4 T cells resolve mouse cytomegalovirus persistent replication in the salivary gland.

Conventional antiviral memory CD4 T cells typically arise during the first two weeks of acute infection. Unlike most viruses, cytomegalovirus (CMV) exhibits an extended persistent replication phase followed by lifelong latency accompanied with some gene expression. We show that during mouse CMV (MCMV) infection, CD4 T cells recognizing an epitope derived from the viral M09 protein only develop after conventional memory T cells have already peaked and contracted. Ablating these CD4 T cells by mutating the M09 genomic epitope in the MCMV Smith strain, or inducing them by introducing the epitope into the K181 strain, resulted in delayed or enhanced control of viral persistence, respectively. These cells were shown to be unique compared to their conventional memory counterparts; producing higher IFNγ and IL-2 and lower IL-10 levels. RNAseq analyses revealed them to express distinct subsets of effector genes as compared to classical CD4 T cells. Additionally, when M09 cells were induced by epitope vaccination they significantly enhanced protection when compared to conventional CD4 T cells alone. These data show that late-rising CD4 T cells are a unique memory subset with excellent protective capacities that display a development program strongly differing from the majority of memory T cells.

CTLA-4 blockade induces a microglia-Th1 cell partnership that stimulates microglia phagocytosis and anti-tumor function in glioblastoma.

The limited efficacy of immunotherapies against glioblastoma underscores the urgency of better understanding immunity in the central nervous system. We found that treatment with αCTLA-4, but not αPD-1, prolonged survival in a mouse model of mesenchymal-like glioblastoma. This effect was lost upon the depletion of CD4+ T cells but not CD8+ T cells. αCTLA-4 treatment increased frequencies of intratumoral IFNγ-producing CD4+ T cells, and IFNγ blockade negated the therapeutic impact of αCTLA-4. The anti-tumor activity of CD4+ T cells did not require tumor-intrinsic MHC-II expression but rather required conventional dendritic cells as well as MHC-II expression on microglia. CD4+ T cells interacted directly with microglia, promoting IFNγ-dependent microglia activation and phagocytosis via the AXL/MER tyrosine kinase receptors, which were necessary for tumor suppression. Thus, αCTLA-4 blockade in mesenchymal-like glioblastoma promotes a CD4+ T cell-microglia circuit wherein IFNγ triggers microglia activation and phagocytosis and microglia in turn act as antigen-presenting cells fueling the CD4+ T cell response.

Canonical BAF complex activity shapes the enhancer landscape that licenses CD8+ T cell effector and memory fates.

CD8+ T cells provide host protection against pathogens by differentiating into distinct effector and memory cell subsets, but how chromatin is site-specifically remodeled during their differentiation is unclear. Due to its critical role in regulating chromatin and enhancer accessibility through its nucleosome remodeling activities, we investigated the role of the canonical BAF (cBAF) chromatin remodeling complex in antiviral CD8+ T cells during infection. ARID1A, a subunit of cBAF, was recruited early after activation and established de novo open chromatin regions (OCRs) at enhancers. Arid1a deficiency impaired the opening of thousands of activation-induced enhancers, leading to loss of TF binding, dysregulated proliferation and gene expression, and failure to undergo terminal effector differentiation. Although Arid1a was dispensable for circulating memory cell formation, tissue-resident memory (Trm) formation was strongly impaired. Thus, cBAF governs the enhancer landscape of activated CD8+ T cells that orchestrates TF recruitment and activity and the acquisition of specific effector and memory differentiation states.

Multiomics atlas-assisted discovery of transcription factors enables specific cell state programming.

The same types of cells can assume diverse states with varying functionalities. Effective cell therapy can be achieved by specifically driving a desirable cell state, which requires the elucidation of key transcription factors (TFs). Here, we integrated epigenomic and transcriptomic data at the systems level to identify TFs that define different CD8 + T cell states in an unbiased manner. These TF profiles can be used for cell state programming that aims to maximize the therapeutic potential of T cells. For example, T cells can be programmed to avoid a terminal exhaustion state (Tex Term ), a dysfunctional T cell state that is often found in tumors or chronic infections. However, Tex Term exhibits high similarity with the beneficial tissue-resident memory T states (T RM ) in terms of their locations and transcription profiles. Our bioinformatic analysis predicted Zscan20 , a novel TF, to be uniquely active in Tex Term . Consistently, Zscan20 knock-out thwarted the differentiation of Tex Term in vivo , but not that of T RM . Furthermore, perturbation of Zscan20 programs T cells into an effector-like state that confers superior tumor and virus control and synergizes with immune checkpoint therapy. We also identified Jdp2 and Nfil3 as powerful Tex Term drivers. In short, our multiomics-based approach discovered novel TFs that enhance anti-tumor immunity, and enable highly effective cell state programming. One sentence summary: Multiomics atlas enables the systematic identification of cell-state specifying transcription factors for therapeutic cell state programming.

Early Chromatin Remodeling Events in Acutely Stimulated CD8+ T Cells.

T cells undergo extensive chromatin remodeling over several days following stimulation through the T cell receptor. However, the kinetics and gene loci targeted by early remodeling events within the first 24 hours of T cell priming to orchestrate effector differentiation have not been well described. We identified that chromatin accessibility is rapidly and extensively remodeled within 1 hour of stimulation of naïve CD8+ T cells, leading to increased global chromatin accessibility at many effector T cell-associated genes that are enriched for AP-1, early growth response (EGR), and nuclear factor of activated T cells (NFAT) binding sites, but this short duration of stimulation is insufficient for commitment to clonal expansion in vivo. Sustained 24-hour stimulation led to further chromatin remodeling and was sufficient to enable clonal expansion. These data suggest that the duration of antigen receptor signaling is intimately coupled to chromatin remodeling and activation of genes involved in effector cell differentiation and highlight a potential mechanism that helps CD8+ T cells discriminate between foreign- and self-antigens.

Tuberous xanthoma secondary to homozygous familial hypercholesterolaemia: a life-threatening diagnosis.

We report the case of a 9-year-old girl who presented with asymptomatic lesions on the extensor surfaces of the elbows and knees, in keeping with tuberous xanthoma. She was investigated and diagnosed with homozygous familial hypercholesterolaemia, and commenced on lipid-lowering treatment. We highlight the importance of identification of this condition early, such that life-saving treatment can be initiated and premature death avoided. Click here for the corresponding questions to this CME article.

SMAD4 and TGFß are architects of inverse genetic programs during fate determination of antiviral CTLs.

Transforming growth factor ß (TGFß) is an important differentiation factor for cytotoxic T lymphocytes (CTLs) and alters the expression levels of several of homing receptors during infection. SMAD4 is part of the canonical signaling network used by members of the transforming growth factor family. For this study, genetically modified mice were used to determine how SMAD4 and TGFß receptor II (TGFßRII) participate in transcriptional programming of pathogen-specific CTLs. We show that these molecules are essential components of opposing signaling mechanisms, and cooperatively regulate a collection of genes that determine whether specialized populations of pathogen-specific CTLs circulate around the body, or settle in peripheral tissues. TGFß uses a canonical SMAD-dependent signaling pathway to downregulate Eomesodermin (EOMES), KLRG1, and CD62L, while CD103 is induced. Conversely, in vivo and in vitro data show that EOMES, KLRG1, CX3CR1, and CD62L are positively regulated via SMAD4, while CD103 and Hobit are downregulated. Intravascular staining also shows that signaling via SMAD4 promotes formation of long-lived terminally differentiated CTLs that localize in the vasculature. Our data show that inflammatory molecules play a key role in lineage determination of pathogen-specific CTLs, and use SMAD-dependent signaling to alter the expression levels of multiple homing receptors and transcription factors with known functions during memory formation.

Modeling of Temporal Exposure to the Ambient Environment and Eczema Severity.

Atopic eczema is a common and complex disease. Missing genetic hereditability and increasing prevalence in industrializing nations point toward an environmental driver. We investigated the temporal association of weather and pollution parameters with eczema severity. This cross-sectional clinical study was performed between May 2018 and March 2020 and is part of the Tower Hamlets Eczema Assessment. All participants had a diagnosis of eczema, lived in East London, were of Bangladeshi ethnicity, and were aged <31 years. The primary outcome was the probability of having an Eczema Area and Severity Index score > 10 after previous ambient exposure to commonly studied meteorological variables and pollutants. There were 430 participants in the groups with Eczema Area and Severity Index ≤ 10 and 149 in those with Eczema Area and Severity Index > 10. Using logistic generalized additive models and a model selection process, we found that tropospheric ozone averaged over the preceding 270 days was strongly associated with eczema severity alongside the exposure to fine particles with diameters of 2.5 µm or less (fine particulate matter) averaged over the preceding 120 days. In our models and analyses, fine particulate matter appeared to largely act in a supporting role to ozone. We show that long-term exposure to ground-level ozone at high levels has the strongest association with eczema severity.

Uptake of oxidized lipids by the scavenger receptor CD36 promotes lipid peroxidation and dysfunction in CD8+ T cells in tumors.

A common metabolic alteration in the tumor microenvironment (TME) is lipid accumulation, a feature associated with immune dysfunction. Here, we examined how CD8+ tumor infiltrating lymphocytes (TILs) respond to lipids within the TME. We found elevated concentrations of several classes of lipids in the TME and accumulation of these in CD8+ TILs. Lipid accumulation was associated with increased expression of CD36, a scavenger receptor for oxidized lipids, on CD8+ TILs, which also correlated with progressive T cell dysfunction. Cd36-/- T cells retained effector functions in the TME, as compared to WT counterparts. Mechanistically, CD36 promoted uptake of oxidized low-density lipoproteins (OxLDL) into T cells, and this induced lipid peroxidation and downstream activation of p38 kinase. Inhibition of p38 restored effector T cell functions in vitro, and resolution of lipid peroxidation by overexpression of glutathione peroxidase 4 restored functionalities in CD8+ TILs in vivo. Thus, an oxidized lipid-CD36 axis promotes intratumoral CD8+ T cell dysfunction and serves as a therapeutic avenue for immunotherapies.

Motility Matters: How CD8+ T-Cell Trafficking Influences Effector and Memory Cell Differentiation.

Immunological memory is a hallmark of adaptive immunity that confers long-lasting protection from reinfections. Memory CD8+ T cells provide protection by actively scanning for their cognate antigen and migrating into inflamed tissues. Trafficking patterns of CD8+ T cells are also a major determinant of cell fate outcomes during differentiation into effector and memory cell states. CD8+ T-cell trafficking must therefore be dynamically and tightly regulated to ensure that CD8+ T cells arrive at the correct locations and differentiate to acquire appropriate effector functions. This review aims to discuss the importance of CD8+ T-cell trafficking patterns in regulating effector and memory differentiation, maintenance, and reactivation.

Fc-Optimized Anti-CCR8 Antibody Depletes Regulatory T Cells in Human Tumor Models.

FOXP3+ regulatory T cells (Treg) play a critical role in mediating tolerance to self-antigens and can repress antitumor immunity through multiple mechanisms. Therefore, targeted depletion of tumor-resident Tregs is warranted to promote effective antitumor immunity while preserving peripheral homeostasis. Here, we propose the chemokine receptor CCR8 as one such optimal tumor Treg target. CCR8 was expressed by Tregs in both murine and human tumors, and unlike CCR4, a Treg depletion target in the clinic, CCR8 was selectively expressed on suppressive tumor Tregs and minimally expressed on proinflammatory effector T cells (Teff). Preclinical mouse tumor modeling showed that depletion of CCR8+ Tregs through an FcyR-engaging anti-CCR8 antibody, but not blockade, enabled dose-dependent, effective, and long-lasting antitumor immunity that synergized with PD-1 blockade. This depletion was tumor Treg-restricted, sparing CCR8+ T cells in the spleen, thymus, and skin of mice. Importantly, Fc-optimized, nonfucosylated (nf) anti-human CCR8 antibodies specifically depleted Tregs and not Teffs in ex vivo tumor cultures from primary human specimens. These findings suggest that anti-CCR8-nf antibodies may deliver optimal tumor-targeted Treg depletion in the clinic, providing long-term antitumor memory responses while limiting peripheral toxicities. SIGNIFICANCE: These findings show that selective depletion of regulatory T cells with an anti-CCR8 antibody can improve antitumor immune responses as a monotherapy or in combination with other immunotherapies. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/11/2983/F1.large.jpg.

The architectural design of CD8+ T cell responses in acute and chronic infection: Parallel structures with divergent fates.

In response to infection, T cells adopt a range of differentiation states, creating numerous heterogeneous subsets that exhibit different phenotypes, functions, and migration patterns. This T cell heterogeneity is a universal feature of T cell immunity, needed to effectively control pathogens in a context-dependent manner and generate long-lived immunity to those pathogens. Here, we review new insights into differentiation state dynamics and population heterogeneity of CD8+ T cells in acute and chronic viral infections and cancer and highlight the parallels and distinctions between acute and chronic antigen stimulation settings. We focus on transcriptional and epigenetic networks that modulate the plasticity and terminal differentiation of antigen-specific CD8+ T cells and generate functionally diverse T cell subsets with different roles to combat infection and cancer.

Real life data on the biopsychosocial effects of Adalimumab in the management of hidradenitis suppurativa: A multicenter cross sectional analysis and consideration of a multisystem monitoring approach to follow up.

Hidradenitis suppurativa (HS) is a chronic relapsing, remitting disease which results in the formation of inflammatory nodules and pustules in intertriginous areas. HS is a complex disease with known psychosocial impact. Adalimumab is a biologic, used for treatment resistant HS, which working by inactivating TNF-alpha. Our primary objective was to determine the effects of adalimumab on HS-PGA and DLQI scores in patients with HS that had been on the treatment for at least 6 months. Our secondary objective was to note and assess the significance of adverse effects and impacts on wider health, namely occupational and social. A retrospective cross-sectional study was performed using clinic notes from routine follow ups in biologic clinics in three specialist HS centers. About 77% (n = 78/101) patients demonstrated improvements in their HS-PGA scores. Significant improvements in the DLQI scores of the patient cohort (P = .0001, 95% CI -12.8 to -5.9) have also been demonstrated. A total of 31.7% (32/101) patients experienced adverse effects spanning multiple organ systems, with 27.7% (28/101) requiring treatment cessation. Three of these patients stopped due to the worsening of preexisting mental health symptoms. Adalimumab is effective in reducing HS-PGA and DLQI scores, but patients still complain of systemic effects necessitating drug cessation in some instances. A holistic and multisystemic approach to follow up is required, and there is scope for further studies examining temporal causality in the context of adalimumab and its multisystemic physical and psychological effects.

Heterogenous Populations of Tissue-Resident CD8+ T Cells Are Generated in Response to Infection and Malignancy.

Tissue-resident memory CD8+ T cells (Trm) provide host protection through continuous surveillance of non-lymphoid tissues. Using single-cell RNA-sequencing (scRNA-seq) and genetic reporter mice, we identified discrete lineages of intestinal antigen-specific CD8+ T cells, including a Blimp1hiId3lo tissue-resident effector cell population most prominent in the early phase of acute viral and bacterial infections and a molecularly distinct Blimp1loId3hi tissue-resident memory population that subsequently accumulated at later infection time points. These Trm populations exhibited distinct cytokine production, secondary memory potential, and transcriptional programs including differential roles for transcriptional regulators Blimp1, T-bet, Id2, and Id3 in supporting and maintaining intestinal Trm. Extending our analysis to malignant tissue, we also identified discrete populations of effector-like and memory-like CD8+ T cell populations with tissue-resident gene-expression signatures that shared features of terminally exhausted and progenitor-exhausted T cells, respectively. Our findings provide insight into the development and functional heterogeneity of Trm cells, which has implications for enhancing vaccination and immunotherapy approaches.

Dose Escalation Assessment Among Targeted Immunomodulators in the Management of Inflammatory Bowel Disease.

BACKGROUND: The need for individualized treatment regimens is becoming more important in the management of patients with inflammatory bowel disease (IBD). Gastroenterologists may dose adjust either by increasing the dose or shortening the dosing interval from the initial recommended maintenance dose to achieve an appropriate clinical response. Understanding the role of dose escalation in the treatment of IBD in clinical practice provides payers in the United States insight into the real-world cost-effectiveness of targeted immunomodulators (TIMs) in the management of IBD. OBJECTIVE: To assess the prevalence and magnitude of dose escalation for approved IBD therapies. METHODS: Using the Source Healthcare Analytics database, patients with IBD who initiated treatment with a drug of interest from July 2015 to June 2017 were identified. Patient utilization of the TIMs was tracked for 12 months following initiation. All included patients had at least 2 diagnoses for ulcerative colitis or Crohn disease before TIM initiation and at least 5 claims for a drug of interest within the 12 months following initiation. Dose escalation was defined as an increase of at least 30% in the average daily dose (ADD) relative to the patient's expected maintenance dose on 2 consecutive prescriptions. The proportion of patients with dose escalation in the first 12 months after treatment initiation was determined. The magnitude of dose escalation was determined by calculating the patient's ADD across all noninduction dose claims and comparing it with the expected daily dose. Dose escalation prevalence and magnitude were used to quantify the equivalent patient treatment rate representing the number of patients per 100 that could have been treated with standard dosing, given the prevalence of dose escalation in the treated population. RESULTS: 7,028 patients (2,406 infliximab, 1,966 adalimumab, 1,745 vedolizumab, 472 ustekinumab, 285 certolizumab pegol, and 154 golimumab) met eligibility criteria and were included in the study. Among IBD therapies, dose escalation occurred most frequently with infliximab (39%), followed by adalimumab (28%), vedolizumab (23%), ustekinumab (22%), certolizumab pegol (20%), and golimumab (14%). The magnitude of dose escalation was greatest for ustekinumab (131%), followed by infliximab (70%), vedolizumab (62%), adalimumab (59%), certolizumab pegol (50%), and golimumab (45%). The calculated patient equivalence was highest for infliximab (128) and ustekinumab (128) compared with adalimumab (116), vedolizumab (114), certolizumab pegol (110), and golimumab (106). CONCLUSIONS: Among patients with IBD, dose escalation occurred with all TIMs examined with varying degrees of prevalence and magnitude. Real-world utilization patterns of TIMs indicate that dose escalation is an important part of the clinical management of IBD and needs to be considered when evaluating the cost-effectiveness of IBD treatments. DISCLOSURES: Financial support for this study was provided by AbbVie, which participated in study design, research, data collection, analysis and interpretation of data, writing, reviewing, and approving the publication. All authors contributed to the development of the publication and maintained control over the final content. Ehrenberg and McDonald are employees of IQVIA, which received funding from AbbVie to participate in this research. Griffith and Theigs are employed by AbbVie and may own stock or stock options in AbbVie.

Cytomegalovirus Evades TRAIL-Mediated Innate Lymphoid Cell 1 Defenses.

Cytomegalovirus (CMV) establishes a lifelong infection facilitated, in part, by circumventing immune defenses mediated by tumor necrosis factor (TNF)-family cytokines. An example of this is the mouse CMV (MCMV) m166 protein, which restricts expression of the TNF-related apoptosis-inducing ligand (TRAIL) death receptors, promoting early-phase replication. We show here that replication of an MCMV mutant lacking m166 is also severely attenuated during viral persistence in the salivary glands (SG). Depleting group I innate lymphoid cells (ILCs) or infecting Trail-/- mice completely restored persistent replication of this mutant. Group I ILCs are comprised of two subsets, conventional natural killer cells (cNK) and tissue-resident cells often referred to as innate lymphoid type I cells (ILC1). Using recently identified phenotypic markers to discriminate between these two cell types, their relative expression of TRAIL and gamma interferon (IFN-γ) was assessed during both early and persistent infection. ILC1 were found to be the major TRAIL expressers during both of these infection phases, with cNK expressing very little, indicating that it is ILC1 that curtail replication via TRAIL in the absence of m166-imposed countermeasures. Notably, despite high TRAIL expression by SG-resident ILC1, IFN-γ production by both ILC1 and cNK was minimal at this site of viral persistence. Together these results highlight TRAIL as a key ILC1-utilized effector molecule that can operate in defense against persistent infection at times when other innate control mechanisms may be muted and highlight the importance for the evolution of virus-employed countermeasures.IMPORTANCE Cytomegalovirus (a betaherpesvirus) is a master at manipulating immune responses to promote its lifelong persistence, a result of millions of years of coevolution with its host. Using a one-of-a-kind MCMV mutant unable to restrict expression of the TNF-related apoptosis-inducing ligand death receptors (TRAIL-DR), we show that TRAIL-DR signaling significantly restricts both early and persistent viral replication. Our results also reveal that these defenses are employed by TRAIL-expressing innate lymphoid type I cells (ILC1) but not conventional NK cells. Overall, our results are significant because they show the key importance of viral counterstrategies specifically neutralizing TRAIL effector functions mediated by a specific, tissue-resident subset of group I ILCs.

cGAS-STING Signaling Regulates Initial Innate Control of Cytomegalovirus Infection.

UNLABELLED: Several innate sensing pathways contribute to the control of early cytomegalovirus (CMV) infection, leading to a multiphasic type I interferon (IFN-I) response that limits viral replication and promotes host defenses. Toll-like receptor (TLR)-dependent pathways induce IFN-I production in CMV-infected plasmacytoid dendritic cells; however, the initial burst of IFN-I that occurs within the first few hours in vivo is TLR independent and emanates from stromal cells. Here we show that primary human endothelial cells mount robust IFN-I responses to human CMV that are dependent upon cyclic GMP-AMP synthase (cGAS), STING, and interferon regulatory factor 3 (IRF3) signaling. Disruption of STING expression in endothelial cells by clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 revealed that it is essential for the induction of IFN-I and restriction of CMV replication. Consistently, STING was necessary to mount the first phase of IFN-I production and curb CMV replication in infected mice. Thus, DNA sensing through STING is critical for primary detection of both human and mouse CMV in nonhematopoietic cells and drives the initial wave of IFN-I that is key for controlling early viral replication in vivo. IMPORTANCE: Cytomegalovirus (CMV) is one of the most common viral pathogens, with the majority of people contracting the virus in their lifetime. Although acute infection is mostly asymptomatic in healthy persons, significant pathology is observed in immunocompromised individuals, and chronic CMV infection may exacerbate a myriad of inflammatory conditions. Here we show that primary human endothelial cells mount robust IFN-I responses against CMV via a cGAS/STING/IRF3 pathway. Disruption of STING expression by CRISPRs revealed an essential role in eliciting IFN-I responses and restricting CMV replication. Consistently, in mice, STING is necessary for the first phase of IFN-I production that limits early CMV replication. Our results demonstrate a pivotal role for the cGAS-STING pathway in the initial detection of CMV infection.

Cytomegalovirus-Specific CD4 T Cells Are Cytolytic and Mediate Vaccine Protection.

UNLABELLED: CD4 T cells provide protection against cytomegalovirus (CMV) and other persistent viruses, and the ability to quantify and characterize epitope-specific responses is essential to gain a more precise understanding of their effector roles in this regard. Here, we report the first two I-A(d)-restricted CD4 T cell responses specific for mouse CMV (MCMV) epitopes and use a major histocompatibility complex class II (MHC-II) tetramer to characterize their phenotypes and functions. We demonstrate that MCMV-specific CD4 T cells can express high levels of granzyme B and kill target cells in an epitope- and organ-specific manner. In addition, CD4 T cell epitope vaccination of immunocompetent mice reduced MCMV replication in the same organs where CD4 cytotoxic T lymphocyte (CTL) activity was observed. Together, our studies show that MCMV epitope-specific CD4 T cells have the potential to mediate antiviral defense by multiple effector mechanisms in vivo. IMPORTANCE: CD4 T cells mediate immune protection by using their T cell receptors to recognize specific portions of viral proteins, called epitopes, that are presented by major histocompatibility complex class II (MHC-II) molecules on the surfaces of professional antigen-presenting cells (APCs). In this study, we discovered the first two epitopes derived from mouse cytomegalovirus (MCMV) that are recognized by CD4 T cells in BALB/c mice, a mouse strain commonly used to study the pathogenesis of this virus infection. Here, we report the sequences of these epitopes, characterize the CD4 T cells that recognize them to fight off MCMV infection, and show that we can use the epitopes to vaccinate mice and protect against MCMV.