Eosinophil Recruitment Research Articles

THOR-707: Using synthetic biology to reprogram the therapeutic activity of interleukin-2 (IL-2).

2603 Background: Recombinant interleukin-2 (rIL-2; aldesleukin) is an approved immunotherapy in melanoma and renal cell carcinoma based on complete durable remissions. The anti-neoplastic properties of IL-2 are mediated by interactions with the beta-gamma chain (IL-2Rβγ) on naïve CD8+ T cells, which lead to their expansion and differentiation into T effector and T memory cells directed against the tumor. However, the widespread use of IL-2 in oncology is limited by interaction with the high affinity IL-2 receptor alpha chain (IL-2R⍺) on regulatory CD4+ T cells (Tregs), which leads to immunosuppression, and on innate lymphoid cells in the vascular endothelium, which leads to eosinophilic recruitment and activation, and the sometimes fatal complication of vascular leak syndrome (VLS). A rIL-2 biased toward IL-2βγ affinity with no IL-2R⍺interaction could fill unmet needs in oncology. Methods: Using a synthetic biology platform, we have engineered THOR-707, a rIL-2 that contains a novel amino acid encoded in the IL-2 gene via a new DNA base pair (X-Y). The novel amino acid serves as a hook for site specific pegylation that extends half-life, blocks IL-2R⍺ engagement and binds to the IL-2Rβγ. Results: In non-human primates, THOR-707 can be dosed to maximize the level of cytotoxic CD8+ T lymphocytes without elevation of VLS-inducing eosinophils. In murine tumor models, THOR-707 induced the expansion of peripheral and intratumoral CD8+ T cells without expansion of suppressive Tregs. Single-agent dose-dependent anti-tumor efficacy was observed in two syngeneic mouse models. In combination with a PD-1 inhibitor, survival of tumor-bearing mice was longer than either agent as monotherapy. Efficacy in tumor models was durable, suggesting activation of CD8+ memory T cell populations. Conclusions: THOR-707 is a reprogrammed, site-directed, singly-pegylated rIL-2 that changes the pharmacologic profile of IL-2, potentially providing a favorable risk-benefit profile. First-in-human studies are expected to begin this year evaluating THOR-707 as monotherapy and in combination with a PD-1 inhibitor. Based on preclinical evidence to-date, THOR-707 may potentially address existing and emerging unmet needs across multiple solid tumors.

Sublingual Immunotherapy Attenuates Nasal Symptoms Upon Allergen Exposure in Murine Allergic Rhinitis Model via an Induction of IL-10 producing T cells in Submandibular Lymph Node.

Sublingual immunotherapy has been considered to be a painless and effective therapeutic treatment of patients with allergic rhinitis. Its mechanism of action has been elucidated, but there are still controversies among many reports between clinical efficacy and laboratory data. Therefore, its mechanism of action needs to be investigated further by using promising animal models such as rodents and monkeys. Bearing this in mind, in our present study, we successfully constructed an effective murine model for sublingual immunotherapy (SLIT) in allergic rhinitis in which mice were sublingually administered ovalbumin (OVA), followed by intraperitoneal (ip) sensitization and intranasal (i.n.) challenge of OVA. To summarize our experimental data, nasal symptoms such as sneezing and nasal rubbing of sublingually treated mice were significantly attenuated in accordance with lower specific IgE antibodies in sera. Histological analysis of eosinophil recruitment in nasal mucosae reveals less allergic inflammation in sublingually treated mice. Interleukin-10 (IL-10) production and IL-10-specific mRNA gene expression of cultured submandibular lymph node (SMLN) cells with OVA, obtained from sublingually treated mice, were significantly higher than those of mice without sublingual treatment. These results demonstrate that sublingually introduced antigens can actually attenuate nasal symptoms in a murine allergic rhinitis model upon allergen exposures. Furthermore, our immunological data might indicate an important role of IL-10 producing T cells in SMLN to control nasal allergic reaction.

Reciprocal Inhibition of Adiponectin and Innate Lung Immune Responses to Chitin and Aspergillus fumigatus.

Chitin is a structural biopolymer found in numerous organisms, including pathogenic fungi, and recognized as an immune-stimulating pathogen associated molecular pattern by pattern recognition molecules of the host immune system. However, programming and regulation of lung innate immunity to chitin inhalation in the context of inhalation of fungal pathogens such as Aspergillus fumigatus is complex and our understanding incomplete. Here we report that the systemic metabolism-regulating cytokine adiponectin is decreased in the lungs and serum of mice after chitin inhalation, with a concomitant decrease in surface expression of the adiponectin receptor AdipoR1 on lung leukocytes. Constitutive lung expression of acidic mammalian chitinase resulted in decreased inflammatory cytokine gene expression and neutrophil recruitment, but did not significantly affect lung adiponectin transcription. Exogenous recombinant adiponectin specifically dampened airway chitin-mediated eosinophil recruitment, while adiponectin deficiency resulted in increased airway eosinophils. The presence of adiponectin also resulted in decreased CCL11-mediated migration of bone marrow-derived eosinophils. In contrast to purified chitin, aspiration of viable conidia from the high chitin-expressing A. fumigatus isolate Af5517 resulted in increased neutrophil recruitment and inflammatory cytokine gene expression in adiponectin-deficient mice, while no significant changes were observed in response to the isolate Af293. Our results identify a novel role for the adiponectin pathway in inhibition of lung inflammatory responses to chitin and A. fumigatus inhalation.

The role of Langerhans cells in pathologies of the skin.

Langerhans cells (LCs) are epidermal immune cells of myeloid origin. Although these cells were primarily thought to play a defensive role in the skin, evidence now indicates a diverse range of LC-mediated effects including the relay of viral antigens in herpes simplex infection, recruitment of eosinophils in atopic dermatitis and promotion of a Th17 response in Candida infection. LCs may have a protective or suppressive function in pathologies of the skin, with differing functions being driven by the skin milieu. Understanding LC function will help guide the development of interventions that modulate these cells for therapeutic benefit.

Group 2 Innate Lymphoid Cells (ILC2): Type 2 Immunity and Helminth Immunity.

Group 2 innate lymphoid cells (ILC2) have emerged as a major component of type 2 inflammation in mice and humans. ILC2 secrete large amounts of interleukins 5 and 13, which are largely responsible for host protective immunity against helminth parasites because these cytokines induce profound changes in host physiology that include: goblet cell metaplasia, mucus accumulation, smooth muscle hypercontractility, eosinophil and mast cell recruitment, and alternative macrophage activation (M2). This review covers the initial recognition of ILC2 as a distinct cell lineage, the key studies that established their biological importance, particularly in helminth infection, and the new directions that are likely to be the focus of emerging work that further explores this unique cell population in the context of health and disease.

Sex-differences in the response to inhaled nanoparticles

Abstract Multi-walled carbon nanotubes (MWCNTs) are a versatile engineered nanomaterial of which the production and integration into consumer products is rapidly expanding. Unfortunately, the risk of occupational and environmental exposures continues to increase, yet long-term consequences and potentially sensitive populations remain undefined. Notably, the respiratory response to MWCNTs closely resembles that seen in asthma, including airway hyper-responsiveness (AHR), Th2-type cytokine production, and eosinophil recruitment to the airways. Based on the similarities in disease pathology and the evidence that asthma occurs most commonly in women of reproductive age, I hypothesized that female animals would be more sensitive to MWCNTs than males. Male and female C57BL/6 mice were exposed to a single dose of MWCNTs or exposed once per week for 4 weeks and harvested 8-weeks after the last exposure. Lung lavage fluid was analyzed for cytokine expression and immune cell recruitment; histology was performed on lung sections. Comparable to the results seen in asthma, female animals mounted a greater Th2-type immune response and subsequent lung pathology. At all time points airway eosinophil recruitment and IL-33 expression, key mediators in both allergic asthma and MWCNT-induced inflammation, were significantly elevated in females compared to males. Lung pathology in the repeated, long-term exposure study reflected the differences seen in the acute response and was more severe in female animals than in males. The next step in this project is to investigate the modification of alveolar macrophage phenotype through steroid hormone signaling as an explanation for the sex-differences observed. Work supported by R01 ES023209.

A role for group 2 innate lymphoid cells in muscular dystrophy

Abstract Duchenne muscular dystrophy (DMD) is a genetic neuromuscular disorder characterized by progressive myofiber degeneration and chronic inflammation. Asynchronous and continuous bouts of injury dysregulate the immune response to injured myofibers, exacerbating muscle degeneration and impairing regeneration. In contrast, activation of type 2 immunity during acute injury is required for efficient muscle regeneration. Evidence in the literature suggests a similar type 2 immune response is activated in dystrophic muscle, but is dysregulated by competing degenerative inflammatory responses. However, the regulation of type 2 immunity in dystrophic muscle is largely unknown. A recently identified subset of immune cells, group 2 innate lymphoid cells (ILC2), were shown to potently regulate type 2 immunity and promote tissue repair. In this study, we found that muscle ILC2s were increased in number and expressed higher levels of interleukin-5 (IL-5) in mdx mice compared to wildtype controls, indicating that muscle degeneration activates ILC2s. In vivo expansion of ILC2s using IL-2/anti-IL-2 complex (IL-2c) and IL-33 enhanced type 2 cytokine expression in mdx skeletal muscle and increased the cross-sectional area of regenerating myofibers, suggesting that ILC2s enhance muscle regeneration through the upregulation of type 2 cytokines. In addition, loss-and gain-of-function experiments demonstrated that ILC2s promote the skeletal muscle recruitment of eosinophils, an innate immune cell population previously shown to promote muscle regeneration. Collectively our data support a working model in which ILC2s promote skeletal muscle regeneration by enhancing type 2 immunity (i.e. eosinophilia and increased type 2 cytokines).

The transcriptional repressor Blimp-1 promotes Th2 development and lung inflammatory disease in a house dust mite induced model of allergic asthma

Abstract Asthma is a T cell-mediated chronic inflammatory lung disease that is thought of as a type 2/Th2 disease, yet precisely how Th2 cell development in the lung is initiated is unknown. Blimp-1 is a transcriptional repressor that regulates effector T cell responses to constrain T cell-mediated autoimmunity. We describe Blimp-1 as an unexpected regulator of allergen-induced airway inflammation that is critical to promote Th2 cell development in the lung and subsequent airway inflammation. Using a house dust mite (HDM) antigen model to drive allergic lung disease, we show that the T cell specific absence of Blimp-1 leads to reduced lung inflammation, a significant decrease in eosinophil recruitment to the lung tissue, and a near absence of Th2 cells in the lung. Intriguingly, Th1 and Th17 responses are intact, suggesting Blimp-1 is specifically required for Th2 differentiation in this model. Furthermore, despite a lack of Th2 cells in the lung, IgE responses are intact, dissociating IL-4-mediated antibody driven responses from Th2 cells in the lung. Bcl6 expression is increased in both the draining lymph node and lung and using T cell specific Bcl6 and Blimp-1 double deficient mice, we find that Th2 cells are restored when Bcl6 is deleted in addition to Blimp-1. Bcl6 is a potent repressor of GATA3, suggesting Blimp-1 acts to indirectly promote GATA3 expression by suppression of Bcl6. Furthermore, we show that STAT3 signaling in T cells is responsible to upregulate Blimp-1 and subsequent Th2 development, implicating this pathway as a possible therapeutic target. Taken together, our data suggests Blimp-1 plays an unexpected and context-dependent role in allergic lung inflammation to promote Th2 cell differentiation and subsequent lung disease.

Epithelial Expression of an Interstitial Lung Disease-Associated Mutation in Surfactant Protein-C Modulates Recruitment and Activation of Key Myeloid Cell Populations in Mice.

Patients with idiopathic pulmonary fibrosis (IPF) often experience precipitous deteriorations, termed "acute exacerbations" (AE), marked by diffuse alveolitis and altered gas exchange, resulting in a significant loss of lung function or mortality. The missense isoleucine to threonine substitution at position 73 (I73T) in the alveolar type 2 cell-restricted surfactant protein-C (SP-C) gene (SFTPC) has been linked to clinical IPF. To better understand the sequence of events that impact AE-IPF, we leveraged a murine model of inducible SP-CI73T (SP-CI73T/I73TFlp+/- ) expression. Following administration of tamoxifen to 8-12-wk-old mice, an upregulation of SftpcI73T initiated a diffuse lung injury marked by increases in bronchoalveolar lavage fluid (BALF) protein and histochemical evidence of CD45+ and CD11b+ cell infiltrates. Flow cytometry of collagenase-digested lung cells revealed a transient, early reduction in SiglecFhiCD11blowCD64hiCD11chi macrophages, countered by the sequential accumulation of SiglecFloCD11b+CD64-CD11c-CCR2+Ly6C+ immature macrophages (3 d), Ly6G+ neutrophils (7 d), and SiglecFhiCD11bhiCD11clo eosinophils (2 wk). By mRNA analysis, BALF cells demonstrated a time-dependent phenotypic shift from a proinflammatory (3 d) to an anti-inflammatory/profibrotic activation state, along with serial elaboration of monocyte and eosinophil recruitment factors. The i.v. administration of clodronate effectively reduced total BALF cell numbers, CCR2+ immature macrophages, and eosinophil influx while improving survival. In contrast, resident macrophage depletion from the intratracheal delivery of clodronate liposomes enhanced SftpcI73T -induced mortality. These results using SftpcI73T mice provide a detailed ontogeny for AE-IPF driven by alveolar epithelial dysfunction that induces a polycellular inflammation initiated by the early influx of proinflammatory CCR2+Ly6Chi immature macrophages.

Perturbation of Developmental Hematopoiesis Shapes Lung ILC2 Immune Memory

Abstract Our lab has previously identified a developmentally-restricted hematopoietic stem cell (drHSC) that only exists in the perinatal period and specifically gives rise to innate-like lymphocytes. The identification of a developmentally-limited cell of origin for innate-like immune cells that persist across the lifespan defines a “critical window” for immune development, in which the phenotype of the adult immune system can be shaped by extrinsic inputs. To test how developmental perturbation during this critical window drives immune dysfunction, we examined underlying changes to innate-like immune cells in the lung and susceptibility to airway dysfunction following maternal immune stimulation. Lung type-2 innate lymphoid cells (ILC2s) are recognized as potent producers of IL5 and IL13, cytokines important for eosinophil recruitment, activation and goblet cell hyperplasia during allergic airway inflammation. Surprisingly, maternal immune stimulation via a single low-dose injection of poly (i:c) at mid-gestation robustly increased the cellularity of lung ILC2s in offspring at postnatal day 14, concomitant with drHSC and ILC2 progenitor expansion during fetal development. Additionally, lung ILC2s exhibited heightened IL5 and IL13 production upon in-vitro stimulation with PMA and ionomycin in poly (i:c) perturbed offspring. Ongoing experiments examine how altered ILC2 functionality, as a result of developmental perturbation, underlie susceptibility to allergic asthma in response to secondary house-dust mite immune stimulation. Together, our data suggest perinatal immune perturbation may contribute to allergic asthma susceptibility by altering drHSC establishment and training lung ILC2 “innate immune memory”.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Involvement of EP2 and EP4 Receptors in Eosinophilic Esophagitis: A Pilot Study

BackgroundThe prostaglandin D2 receptor DP2 has been implicated in eosinophil infiltration and the development of eosinophilic esophagitis (EoE).Aims and MethodsIn this study, we investigated an involvement of PGE2 (EP1–EP4) and PGD2 (DP1) receptors in EoE by measuring their expression in peripheral blood eosinophils and esophageal mucosal biopsies of EoE patients and by performing migration and adhesion assays with eosinophils from healthy donors.ResultsExpression of EP2 and EP4, but not EP1 and EP3, was decreased in blood eosinophils of patients with EoE vs. control subjects. Adhesion of eosinophils to esophageal epithelial cells was decreased by EP2 receptor agonist butaprost and EP4 agonist ONO-AE1-329, whereas DP1 agonist BW245C increased adhesion. In chemotaxis assays with supernatant from human esophageal epithelial cells, only ONO-AE1-329 but not butaprost or BW245C inhibited the migration of eosinophils. Expression of EP and DP receptors in epithelial cells and eosinophils was detected in sections of esophageal biopsies from EoE patients by immunohistochemistry. qPCR of biopsies from EoE patients revealed that gene expression of EP4 and DP1 was the highest among PGE2 and PGD2 receptors. Esophageal epithelial cells in culture showed high gene expression for EP2 and EP4. Activation of EP2 and EP4 receptors decreased barrier integrity of esophageal epithelial cells in impedance assays.ConclusionsActivation of EP2 and EP4 receptors may inhibit eosinophil recruitment to the esophageal mucosa. However, their activation could negatively affect esophageal barrier integrity suggesting that eosinophilic rather than epithelial EP2 and EP4 have a protective role in EoE.

Epithelium-derived cystatin SN enhances eosinophil activation and infiltration through IL-5 in patients with chronic rhinosinusitis with nasal polyps

The interaction between epithelial cells and immune cells plays an important role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP); however, the mechanism or mechanisms underlying TH-biased inflammation in this process are largely unknown. Profiling protein expression in patients with CRSwNP by using shotgun proteomics suggested that cystatin SN (CST1), a type 2 cysteine protease inhibitor, might play a role because this was expressed with the greatest difference in patients with eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) and those with noneosinophilic chronic rhinosinusitis with nasal polyps (nonECRSwNP). We sought to investigate the expression and role of CST1 in modulating eosinophilic inflammation in patients with CRSwNP. Sinonasal tissues were collected from 192 patients with ECRSwNP, 52 patients with nonECRSwNP, and 40 control subjects. CST1 mRNA expression, localization, and concentration in the tissues were measured by using real-time PCR, in situ hybridization, immunohistochemistry, and an ELISA. Recombinant CST1 was used to further explore the function of the molecule in dispersed nasal polyp cells and eosinophils extracted from polyp tissues and peripheral blood. CST1 was mainly expressed by epithelial cells and significantly increased in patients with ECRSwNP but decreased in patients with nonECRSwNP compared with that in control subjects. CST1 expression was further increased in patients with ECRSwNP and comorbid asthma and correlated with eosinophil percentages in tissue samples. CST1 was induced by IL-4 and IL-13 in tissue from both patients with ECRSwNP and those with nonECRSwNP and repressed by IL-17A in patients with nonECRSwNP in the presence of neutrophils. CST1 enhanced eosinophil activation and recruitment through induction of IL-5. Epithelium-derived CST1 modulates eosinophil activation and recruitment, expression of which could be regulated by TH2 and TH17 cytokines.

Critical role of CCL4 in eosinophil recruitment into the airway.

Excessive eosinophil airway infiltration is a clinically critical condition in some cases. Eosinophilic pneumonia (EP) is a pulmonary condition involving eosinophil infiltration of the lungs. Although several chemokines, including eotaxin-1 (CCL11), RANTES (CCL5) and macrophage inflammatory protein 1β (MIP-1β or CCL4), have been detected in bronchoalveolar lavage fluid (BALF) from patients with EP, the pathophysiological mechanisms underlying EP, including potential relationships between eosinophils and CCL4, have not been fully elucidated. To examine the involvement of CCL4 in eosinophilic airway inflammation. We analysed supernatants of activated eosinophils and BALF from 16 patients with eosinophilic pneumonia (EP). Further, we examined the effects of CCL4 on eosinophil functions in vitro and those of anti-CCL4 neutralizing antibody in an in vivo model. We found that purified human eosinophils stimulated with IL-5 predominantly secreted CCL4 and that patients with EP had elevated CCL11 and CCL4 levels in BALF compared with samples from individuals without EP. Because CCL4 levels were more strongly correlated with eosinophil count and expression of eosinophil granule proteins than CCL11, in vitro experiments using purified eosinophils concentrated on the former chemokine. Interestingly, CCL4 acted as a chemoattractant for eosinophils. In a mouse model, administration of a CCL4-neutralizing antibody attenuated eosinophilic airway infiltration and airway hyperresponsiveness. Overall, these findings highlight an important role of CCL4 in the mechanisms underlying eosinophil recruitment into the airway and may provide a novel insight into this potential therapeutic target.

Eosinophils Mediate Basophil-Dependent Allergic Skin Inflammation in Mice

The mechanisms leading to allergic skin inflammation, such as atopic dermatitis or urticaria, are poorly defined. Here we used a mouse model for IgE-dependent chronic allergic inflammation to study the role of basophils and eosinophils for induction of pathology. FcεRI expression in basophils was required for the ear swelling response, and basophils promoted the expression of eosinophil-recruiting chemokines in the ear. The ear swelling response could be prevented by prior infection of mice with helminths in an IgE-dependent manner. Impaired skin eosinophilia and reduced ear swelling was further observed in IL-4/IL-13-deficient and STAT6-deficient mice. In addition, eosinophil-deficient ΔdblGATA mice showed only weak ear swelling response, which could be enhanced by eosinophil transfer. This suggests that IgE-activated basophils orchestrate the recruitment of eosinophils by secretion of IL-4/IL-13, which leads to STAT6-dependent expression of CCL24 from endothelial cells and extravasation of eosinophils into the ear pinna. Eosinophils are then the critical effector cells that cause pathology. Therefore, combined therapeutic approaches that block basophil activation and reduce eosinophil numbers could be efficient strategies to improve treatment of chronic allergic disorders of the skin.

Inflammatory monocytes are detrimental to the host immune response during acute infection with Cryptococcus neoformans.

Cryptococcus neoformans is a leading cause of invasive fungal infections among immunocompromised patients. However, the cellular constituents of the innate immune response that promote clearance versus progression of infection upon respiratory acquisition of C. neoformans remain poorly defined. In this study, we found that during acute C. neoformans infection, CCR2+ Ly6Chi inflammatory monocytes (IM) rapidly infiltrate the lungs and mediate fungal trafficking to lung-draining lymph nodes. Interestingly, this influx of IM is detrimental to the host, since ablating IM or impairing their recruitment to the lungs improves murine survival and reduces fungal proliferation and dissemination. Using a novel conditional gene deletion strategy, we determined that MHC class II expression by IM did not mediate their deleterious impact on the host. Furthermore, although ablation of IM reduced the number of lymphocytes, innate lymphoid cells, and eosinophils in the lungs, the effects of IM were not dependent on these cells. We ascertained that IM in the lungs upregulated transcripts associated with alternatively activated (M2) macrophages in response to C. neoformans, consistent with the model that IM assume a cellular phenotype that is permissive for fungal growth. We also determined that conditional knockout of the prototypical M2 marker arginase 1 in IM and deletion of the M2-associated transcription factor STAT6 were not sufficient to reverse the harmful effects of IM. Overall, our findings indicate that C. neoformans can subvert the fungicidal potential of IM to enable the progression of infection through a mechanism that is not dependent on lymphocyte priming, eosinophil recruitment, or downstream M2 macrophage polarization pathways. These results give us new insight into the plasticity of IM function during fungal infections and the level of control that C. neoformans can exert on host immune responses.

Eosinophils in Inflammatory Bowel Disease.

Clinical investigations in inflammatory bowel disease (IBD) patients have provided increasing evidence that eosinophils contribute to chronic intestinal inflammation. Accumulation of eosinophils in the gastrointestinal tract correlates with the variations of eosinophil regulatory molecules; however, their role in gastrointestinal dysfunction in IBD has not been fully elucidated. This review will describe the development and characterization of gastrointestinal eosinophils, mechanisms of eosinophil recruitment to the gastrointestinal tract. Moreover, the eosinophil-induced changes to the enteric nervous system associated with disease severity and gastrointestinal dysfunction will be analyzed with suggestive molecular pathways for enteric neuronal injury. Current and potential therapeutic interventions targeting eosinophils will be discussed.

Induction of peripheral lymph node addressin in human nasal mucosa with eosinophilic chronic rhinosinusitis

Eosinophilic chronic rhinosinusitis (ECRS) is characterised by formation of nasal polyps with prominent eosinophilic infiltration; however, how eosinophils are recruited in this pathological setting remains unclear. In the present study, we carried out quantitative immunohistochemical analysis of nasal polyps associated with ECRS (n=30) and non-ECRS (n=30) to evaluate expression of an L-selectin ligand peripheral lymph node addressin (PNAd) on vascular endothelial cells. We found that PNAd was induced primarily on the luminal surface of venular vessels present in nasal mucosa in both ECRS and non-ECRS, while the number of PNAd-expressing vessels in ECRS significantly exceeded that seen in non-ECRS. Moreover, the number of eosinophils attached to the luminal surface of PNAd-expressing vessels in ECRS was significantly greater than that in non-ECRS, while the number of neutrophils and lymphocytes attached did not differ significantly between conditions. Furthermore, eosinophils, which express cell surface L-selectin, adhered to PNAd-expressing Chinese hamster ovary (CHO) cells in a calcium-dependent manner, and that adhesion was significantly inhibited by pretreatment of eosinophils with DREG-56, an anti-human L-selectin monoclonal antibody. These findings combined suggest that interaction between L-selectin and PNAd plays at least a partial role in eosinophil recruitment in human nasal mucosa with ECRS.

Activated Eosinophils Exert Antitumorigenic Activities in Colorectal Cancer.

Immunotherapies targeting T lymphocytes are revolutionizing cancer therapy but only benefit a subset of patients, especially in colorectal cancer. Thus, additional insight into the tumor microenvironment (TME) is required. Eosinophils are bone marrow-derived cells that have been largely studied in the context of allergic diseases and parasite infections. Although tumor-associated eosinophilia has been described in various solid tumors including colorectal cancer, knowledge is still missing regarding eosinophil activities and even the basic question of whether the TME promotes eosinophil recruitment without additional manipulation (e.g., immunotherapy) is unclear. Herein, we report that eosinophils are recruited into developing tumors during induction of inflammation-induced colorectal cancer and in mice with the Apcmin /+ genotype, which develop spontaneous intestinal adenomas. Using adoptive transfer and cytokine neutralization experiments, we demonstrate that the TME supported prolonged eosinophil survival independent of IL5, an eosinophil survival cytokine. Tumor-infiltrating eosinophils consisted of degranulating eosinophils and were essential for tumor rejection independently of CD8+ T cells. Transcriptome and proteomic analysis revealed an IFNγ-linked signature for intratumoral eosinophils that was different from that of macrophages. Our data establish antitumorigenic roles for eosinophils in colorectal cancer. These findings may facilitate the development of pharmacologic treatments that could unleash antitumor responses by eosinophils, especially in colorectal cancer patients displaying eosinophilia.

Sirtuin 2 enhances allergic asthmatic inflammation.

Allergic eosinophilic asthma is a chronic condition causing airway remodeling resulting in lung dysfunction. We observed that expression of sirtuin 2 (Sirt2), a histone deacetylase, regulates the recruitment of eosinophils after sensitization and challenge with a triple antigen: dust mite, ragweed, and Aspergillus fumigatus (DRA). Our data demonstrate that IL-4 regulates the expression of Sirt2 isoform 3/5. Pharmacological inhibition of Sirt2 by AGK2 resulted in diminished cellular recruitment, decreased CCL17/TARC, and reduced goblet cell hyperplasia. YM1 and Fizz1 expression was reduced in AGK2-treated, IL-4-stimulated lung macrophages in vitro as well as in lung macrophages from AGK2-DRA-challenged mice. Conversely, overexpression of Sirt2 resulted in increased cellular recruitment, CCL17 production, and goblet cell hyperplasia following DRA challenge. Sirt2 isoform 3/5 was upregulated in primary human alveolar macrophages following IL-4 and AGK2 treatment, which resulted in reduced CCL17 and markers of alternative activation. These gain-of-function and loss-of-function studies indicate that Sirt2 could be developed as a treatment for eosinophilic asthma.