PD-L1 restrains PD-1Nrp1 Treg cells to suppress inflammation-driven colorectal tumorigenesis.

T cells function not only as an essential component of host cancer immunosurveillance but also as a regulator of colonic inflammation, a process that promotes colorectal cancer. Programmed death-ligand 1 (PD-L1) is a T cell-negative regulator, but its role in regulation of T cell functions in the context of colorectal cancer is unknown. We report that global deletion of Cd274 results in increased colonic inflammation, PD-1 T cells, and inflammation-driven colorectal tumorigenesis in mice.

Mef2d potentiates type-2 immune responses and allergic lung inflammation.

Innate lymphoid cells (ILCs) and adaptive T lymphocytes promote tissue homeostasis and protective immune responses. Their production depends on the transcription factor GATA3, which is further elevated specifically in ILC2s and T helper 2 cells to drive type-2 immunity during tissue repair, allergic disorders, and anti-helminth immunity. The control of this crucial up-regulation is poorly understood.

PD-L1- and IL-4-expressing basophils promote pathogenic accumulation of T follicular helper cells in lupus.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by anti-nuclear autoantibodies whose production is promoted by autoreactive T follicular helper (TFH) cells. During SLE pathogenesis, basophils accumulate in secondary lymphoid organs (SLO), amplify autoantibody production and disease progression through mechanisms that remain to be defined. Here, we provide evidence for a direct functional relationship between TFH cells and basophils during lupus pathogenesis, both in humans and mice.

Type 2 innate lymphoid cells are not involved in mouse bladder tumor development.

Therapies for bladder cancer patients are limited by side effects and failures, highlighting the need for novel targets to improve disease management. Given the emerging evidence highlighting the key role of innate lymphoid cell subsets, especially type 2 innate lymphoid cells (ILC2s), in shaping the tumor microenvironment and immune responses, we investigated the contribution of ILC2s in bladder tumor development. Using the orthotopic murine MB49 bladder tumor model, we found a strong enrichment of ILC2s in the bladder under steady-state conditions, comparable to that in the lung.

4-Octyl Itaconate Alleviates Airway Eosinophilic Inflammation by Suppressing Chemokines and Eosinophil Development.

4-Octyl itaconate (4-OI) is a derivative of the Krebs cycle-derived metabolite itaconate and displays an array of antimicrobial and anti-inflammatory properties through modifying cysteine residues within protein targets. We have found that 4-OI significantly reduces the production of eosinophil-targeted chemokines in a variety of cell types, including M1 and M2 macrophages, Th2 cells, and A549 respiratory epithelial cells. Notably, the suppression of these chemokines in M1 macrophages was found to be NRF2-dependent.

Retinoic Acid-Related Orphan Receptor α Is Required for Generation of Th2 Cells in Type 2 Pulmonary Inflammation.

The transcription factor retinoic acid-related orphan receptor α (RORα) is important in regulating several physiological functions, such as cellular development, circadian rhythm, metabolism, and immunity. In two in vivo animal models of type 2 lung inflammation, Nippostrongylus brasiliensis infection and house dust mite (HDM) sensitization, we show a role for Rora in Th2 cellular development during pulmonary inflammation. N.

Dimethyl fumarate and 4-octyl itaconate are anticoagulants that suppress Tissue Factor in macrophages via inhibition of Type I Interferon.

Excessive inflammation-associated coagulation is a feature of infectious diseases, occurring in such conditions as bacterial sepsis and COVID-19. It can lead to disseminated intravascular coagulation, one of the leading causes of mortality worldwide. Recently, type I interferon (IFN) signaling has been shown to be required for tissue factor (TF; gene name F3) release from macrophages, a critical initiator of coagulation, providing an important mechanistic link between innate immunity and coagulation.

Characterisation of the pro-inflammatory cytokine signature in severe COVID-19.

Clinical outcomes from infection with SARS-CoV-2, the cause of the COVID-19 pandemic, are remarkably variable ranging from asymptomatic infection to severe pneumonia and death. One of the key drivers of this variability is differing trajectories in the immune response to SARS-CoV-2 infection. Many studies have noted markedly elevated cytokine levels in severe COVID-19, although results vary by cohort, cytokine studied and sensitivity of assay used.

Tumor PD-L1 engages myeloid PD-1 to suppress type I interferon to impair cytotoxic T lymphocyte recruitment.

The cellular and molecular mechanisms underlying tumor cell PD-L1 (tPD-L1) function in tumor immune evasion are incompletely understood. We report here that tPD-L1 does not suppress cytotoxic T lymphocyte (CTL) activity in co-cultures of tumor cells and tumor-specific CTLs and exhibits no effect on primary tumor growth. However, deleting tPD-L1 decreases lung metastasis in a CTL-dependent manner in tumor-bearing mice.

Heterogeneity in the half-life of factor VIII concentrate in patients with hemophilia A is due to variability in the clearance of endogenous von Willebrand factor.

Background: Previous studies have reported marked interindividual variation in factor VIII (FVIII) clearance in patients with hemophilia (PWH) and proposed a number of factors that influence this heterogeneity.

Objectives: To investigate the importance of the clearance rates of endogenous von Willebrand factor (VWF) compared with those of other FVIII half-life modifiers in adult PWH.

Methods: The half-life of recombinant FVIII was determined in a cohort of 61 adult PWH.

Macrophage Galactose Lectin Contributes to the Regulation of FVIII (Factor VIII) Clearance in Mice-Brief Report.

Background: Although most plasma FVIII (Factor VIII) circulates in complex with VWF (von Willebrand factor), a minority (3%-5%) circulates as free-FVIII, which is rapidly cleared. Consequently, 20% of total FVIII may be cleared as free-FVIII. Critically, the mechanisms of free-FVIII clearance remain poorly understood.

Ly6C monocytes balance regulatory and cytotoxic CD4 T cell responses to control virus-induced immunopathology.

Gammaherpesviruses (γHVs) have coevolved with their host, leading to a remarkably high infection prevalence and establishment of latency. The lifelong persistence of γHVs in hosts appears to broadly shape host immunity, and we show here that pulmonary infection with Murid herpesvirus 4 (MuHV-4), a mouse γHV, drives the recruitment of Ly6C monocytes (MOs) into the airway, thereby modulating the host immune response. The absence of Ly6C MOs is associated with severe virus-induced immunopathology and the systemic release of inflammatory mediators.

Obesity-Mediated Immune Modulation: One Step Forward, (Th)2 Steps Back.

Over the past decades, the relationship between the immune system and metabolism has become a major research focus. In this arena of immunometabolism the capacity of adipose tissue to secrete immunomodulatory molecules, including adipokines, within the underlying low-grade inflammation during obesity brought attention to the impact obesity has on the immune system. Adipokines, such as leptin and adiponectin, influence T cell differentiation into different T helper subsets and their activation during immune responses.

The IL-1 cytokine family as custodians of barrier immunity.

The interleukin-1 (IL-1) family of cytokines and receptors are implicated in the functioning of innate and adaptive immunity and the genesis of inflammation. They are widely expressed in structural and immune cells with marked expression within barrier mucosal surfaces. In the lung, gut and skin, which are common entry sites for pathogens, they play essential functions in maintaining the functional integrity of the barrier and manage innate and adaptive immunity in response to insult and infections.

Expelliarmus helminthus! Harry Helminth and the Goblet of Alarmins.

Epithelial cells (tuft and goblet cells) interact with immune cells on the "inside" while secreting effector molecules into the topological "outside." In this issue of Immunity, Zhao et al. investigate an interleukin-33 (IL-33) secretion mechanism in goblet cells dependent on O-GlcNAcylation and gasdermin pores facilitating worm expulsion.

When killers become thieves: Trogocytosed PD-1 inhibits NK cells in cancer.

Trogocytosis modulates immune responses, with still unclear underlying molecular mechanisms. Using leukemia mouse models, we found that lymphocytes perform trogocytosis at high rates with tumor cells. While performing trogocytosis, both Natural Killer (NK) and CD8 T cells acquire the checkpoint receptor PD-1 from leukemia cells.

Innate PD-L1 limits T cell-mediated adipose tissue inflammation and ameliorates diet-induced obesity.

Obesity has become a major health problem in the industrialized world. Immune regulation plays an important role in adipose tissue homeostasis; however, the initial events that shift the balance from a noninflammatory homeostatic environment toward inflammation leading to obesity are poorly understood. Here, we report a role for the costimulatory molecule programmed death-ligand 1 (PD-L1) in the limitation of diet-induced obesity.

Itaconate and itaconate derivatives target JAK1 to suppress alternative activation of macrophages.

The Krebs cycle-derived metabolite itaconate and its derivatives suppress the inflammatory response in pro-inflammatory "M1" macrophages. However, alternatively activated "M2" macrophages can take up itaconate. We therefore examined the effect of itaconate and 4-octyl itaconate (OI) on M2 macrophage activation.

IL-36 cytokines imprint a colitogenic phenotype on CD4 T helper cells.

IL-36 cytokines are emerging as potent orchestrators of intestinal inflammation and are being implicated in the pathogenesis of inflammatory bowel diseases (IBD). However, the mechanisms through which these cytokines mediate these effects remain to be fully uncovered. Here, we report specifically elevated expression of IL-36α, and not IL-36β or IL-36γ in the serum of newly diagnosed, treatment naïve, paediatric IBD patients and identify T cells as primary cellular mediators of IL-36 responses in the inflamed gut.

Candidate Role for Toll-like Receptor 3 L412F Polymorphism and Infection in Acute Exacerbation of Idiopathic Pulmonary Fibrosis.

The Toll-like receptor 3 Leu412Phe ( L412F) polymorphism attenuates cellular antiviral responses and is associated with accelerated disease progression in idiopathic pulmonary fibrosis (IPF). The role of L412F in bacterial infection in IPF or in acute exacerbations (AE) has not been reported. To characterize the association between L412F and AE-related death in IPF.

SREBP1-induced fatty acid synthesis depletes macrophages antioxidant defences to promote their alternative activation.

Macrophages exhibit a spectrum of activation states ranging from classical to alternative activation. Alternatively, activated macrophages are involved in diverse pathophysiological processes such as confining tissue parasites, improving insulin sensitivity or promoting an immune-tolerant microenvironment that facilitates tumour growth and metastasis. Recently, the metabolic regulation of macrophage function has come into focus as both the classical and alternative activation programmes require specific regulated metabolic reprogramming.