Tuning IgE: IgE-Associating Molecules and Their Effects on IgE-Dependent Mast Cell Reactions

Emerging trends and therapeutic applications of monoclonal antibodies

Monoclonal antibodies (mAbs) are being used to prevent, detect, and treat a broad spectrum of malignancies and infectious and autoimmune diseases. Over the past few years, the market for mAbs has grown exponentially. They have become a significant part of many pharmaceutical product lines, and more than 250 therapeutic mAbs are undergoing clinical trials. Ever since the advent of hybridoma technology, antibody-based therapeutics were realized using murine antibodies which further progressed into humanized and fully human antibodies, reducing the risk of immunogenicity. Some of the benefits of using mAbs over conventional drugs include a drastic reduction in the chances of adverse reactions, interactions between drugs, and targeting specific proteins. While antibodies are very efficient, their higher production costs impede the process of commercialization. However, their cost factor has been improved by developing biosimilar antibodies, which are affordable versions of therapeutic antibodies. Along with biosimilars, innovations in antibody engineering have helped to design bio-better antibodies with improved efficacy than the conventional ones. These novel mAb-based therapeutics are set to revolutionize existing drug therapies targeting a wide spectrum of diseases, thereby meeting several unmet medical needs. In the future, mAbs generated by applying next-generation sequencing (NGS) are expected to become a powerful tool in clinical therapeutics. This article describes the methods of mAb production, pre-clinical and clinical development of mAbs, approved indications targeted by mAbs, and novel developments in the field of mAb research.

Inhibition of pseudo-allergic reactions by vitamin K3 directly targeting GAB1 in mast cells

BACKGROUND

Vitamin K3 (VK3), a fat-soluble synthetic analog of the vitamin K family, has coagulant, anti-inflammatory, antibacterial, and anticancer properties. Pseudo allergy is a IgE-independent immune response associated with mast cells. This study investigated the role of VK3 in IgE-independent mast cell activation.

METHODS

Substance P (SP) was used to induce LAD2-cell activation in order to analyze the effects of VK3 in vitro. Cutaneous allergy and systemic allergy mouse models were used to analyze the anti-pseudo-allergic effects of VK3. Proteome microarray assays were used to analyze VK3-binding protein. Biolayer interferometry and immunoprecipitation were used to verify interaction between VK3 and its key targets. RNA interference was used to determine the role of GAB1 in LAD2cell activation.

RESULTS

VK3 inhibited SP-induced LAD2-cell activation, and resulted in the release of β-hexosaminidase, histamine and cytokines; VK3 inhibited SP-induced pseudo allergic reactions in mice, and serum histamine and TNF-α levels decreased. Degranulation of skin mast cells was reduced; GAB1 in mast cells was stably bound to VK3. GAB1 participated in SP-induced LAD2-cell activation. GAB1 knockdown in LAD2 cells prevented SP-induced β-hexosaminidase release, calcium mobilization and cell skeletal remodeling. VK3 directly binds to GAB1 and reduces its expression to inhibited SP-induced LAD2 cell activation.

CONCLUSION

The anti-pseudo-allergic activity of VK3 was confirmed in vitro and in vivo. VK3 can inhibit SP-induced mast cell activation by directly targeting GAB1. This study provides new insights on the activity of VK3 and the mechanism of pseudoallergic reaction.

Elafibranor PPARα/δ Dual Agonist Ameliorates Ovalbumin-Induced Allergic Asthma

Asthma is characterized by chronic inflammation and respiratory tract remodeling. Peroxisome proliferator-activated receptors (PPARs) play important roles in the pathogenesis and regulation of chronic inflammatory processes in asthma. The role of PPARγ has been studied using synthetic PPARγ agonists in patients with asthma. However, involvement of PPARα/δ has not been studied in asthma. In the present study, we investigated if elafibranor, a PPARα/δ dual agonist, can modulate ovalbumin (OVA)-induced allergic asthma, which is a potential drug candidate for non-alcoholic fatty liver in obese patients. Elafibranor suppresses antigen-induced degranulation in RBL-2H3 mast cells without inducing cytotoxicity in vitro. In mice with OVA-induced allergic asthma, the administration of elafibranor suppressed OVA-induced airway hyper-responsiveness at a dose of 10 mg/kg. Elafibranor also suppressed the OVA-induced increase in immune cells and pro-inflammatory cytokine production in the bronchoalveolar lavage fluid (BALF). Histological studies suggested that elafibranor suppressed OVA-induced lung inflammation and mucin hyper-production in the bronchial airways. In addition, elafibranor suppressed OVA-induced increases in serum immunoglobulin E and IL-13 levels in BALF. Conversely, the present study suggests that elafibranor has the potential for use in patients with allergic asthma.

Inhibitory effects of catalpol on DNCB-induced atopic dermatitis and IgE-mediated mast cells reaction

Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disease driven by immune dysregulation. Catalpol is an iridoids, possessing anti-inflammatory, antioxidant, and neuroprotective activities. It can be added to food as a dietary supplement. To evaluate the effects and mechanisms of catalpol on AD, both in vitro and in vivo studies were conducted. It was found that catalpol downregulated the phosphorylation of Lyn and Syk to inhibit various downstream pathways, including intracellular Ca2+ elevation, cytokines generation, and histamine release, which ultimately controlled mast cell (MCs) degranulation. The results showed that catalpol alleviated AD-like skin lesions and MC infiltration via regulation of pro-Th2 and Th2 cytokines in vivo. Furthermore, this compound reduced the levels of IgE in AD mice and improved allergic reactions in PCA mice. The results provided that catalpol was potentially developed as a dietary supplement to improve AD and other atopic diseases.

Screening of Prospective Antiallergic Compound as FcεRI Inhibitors and Its Antiallergic Efficacy Through Immunoinformatics Approaches

The occurrence of allergy, a type I hypersensitivity reaction, is rising exponentially all over the world. Sometimes, allergy proves to be fatal for atopic patients, due to the occurrence of anaphylaxis. This study is aimed to find an anti-allergic agent that can inhibit the binding of IgE to Human High Affinity IgE Receptor (FCεRI), thereby preventing the degranulation of mast cells. A considerable number of potential anti-allergic compounds were assessed for their inhibitory strength through ADMET studies. AUTODOCK was used for estimating the binding energy between anti-allergic compounds and FCεRI, along with the interacting amino acids. The docked pose showing favorable binding energy was subjected to molecular dynamics simulation study. Marrubiin, a diterpenoid lactone from Lamiaceae, and epicatechin-3-gallate appears to be effective in blocking the Human High Affinity IgE Receptor (FCεRI). This in-silico study proposes the use of marrubiin and epicatechin-3-gallate, in the downregulation of allergic responses. Due to the better inhibition constant, future direction of this study is to analyze the safety and efficacy of marrubiin in anti-allergic activities through in-vivo clinical human trials.

Enhanced protective immunity against Baylisascaris schroederi infection in mice through a multi-antigen cocktail vaccine approach

Baylisascaris schroederi is among the most severe intestinal nematodes affecting giant pandas. Developing effective and secure vaccines can be used as a novel strategy for controlling repeated roundworm infection and addressing drug resistance. In our previous study, three recombinant antigens (rBsHP2, rBsGAL, and rBsUP) exhibited promising effects against B. schroederi infection in the mice model. This study extends the findings by formulating four-form cocktail vaccines (GAL+UP, HP2+UP, GAL+HP2, and GAL+HP2+UP) using three B. schroederi recombinant antigens to improve protection in mice further. Additionally, the protective differences after immunizing mice with different doses of cocktail antigens (150 μg, 100 μg, and 50 μg) were analyzed. Administration of rBs(GAL+UP), rBs(HP2+UP), rBs(GAL+HP2), and rBs(GAL+HP2+UP) significantly reduced liver and lung lesions, along with a decrease in L3 larvae by 83.7%, 82.1%, 76.4%, and 75.1%, respectively. These vaccines induced a Th1/Th2 mixed immunity, evidenced by elevated serum antibody levels (IgG, IgG1, IgG2a, IgE, and IgA) and splenocyte cytokines [interferon gamma (IFN-γ), interleukin (IL)-5, and IL-10]. Furthermore, varying cocktail vaccine dosages did not significantly affect protection. The results confirm that a 50 μg rBs(GAL+UP) dosage holds promise as a better candidate vaccine combination against B. schroederi infection, providing a basis for developing the B. schroederi vaccine.

Investigating Forkhead Box O Transcription Factor 1 Gene's Relation to Immunoglobulin E in House Dust Mite-Allergic Asthma Patients

House dust mite (HDM)-allergic asthma is an abnormal immune response to extrinsic aeroallergens found in human vicinities. Studying the role of the associated immunity biomarkers and their interplay helps in discovering novel therapeutic strategies that can be used in adjunct with effective long-term immunotherapy. This study investigates the total serum IgE, FoxO1, and Sirtuin 1 (SIRT1) gene expressions in HDM-allergic asthma patients. We enrolled 40 patients for each of the following three groups: an HV group of healthy volunteers and HDM/AA and HDM/SCIT groups of HDM-allergic asthma patients who did not and who did receive immunotherapy before recruitment in this study, respectively. The results elucidated that total IgE was strikingly elevated in the HDM/AA group and showed little decline in the HDM/SCIT group. Both FoxO1 and SIRT1 gene expressions showed the highest levels in the HDM/SCIT group. There was a negative correlation between total IgE and both FoxO1 and SIRT1 in the HDM/AA group while there was a positive correlation with SIRT1 in the HDM/SCIT group. In conclusion, the interplay of the three immunity biomarkers related to HDM-allergic asthma after the course of immunotherapy treatment suggests further, broader studies on the feasibility of their role as immunity biomarkers in the control and remission of HDM-allergic asthma.

Potential Role of Moesin in Regulating Mast Cell Secretion

Mast cells have existed for millions of years in species that never suffer from allergic reactions. Hence, in addition to allergies, mast cells can play a critical role in homeostasis and inflammation via secretion of numerous vasoactive, pro-inflammatory and neuro-sensitizing mediators. Secretion may utilize different modes that involve the cytoskeleton, but our understanding of the molecular mechanisms regulating secretion is still not well understood. The Ezrin/Radixin/Moesin (ERM) family of proteins is involved in linking cell surface-initiated signaling to the actin cytoskeleton. However, how ERMs may regulate secretion from mast cells is still poorly understood. ERMs contain two functional domains connected through a long α-helix region, the N-terminal FERM (band 4.1 protein-ERM) domain and the C-terminal ERM association domain (C-ERMAD). The FERM domain and the C-ERMAD can bind to each other in a head-to-tail manner, leading to a closed/inactive conformation. Typically, phosphorylation on the C-terminus Thr has been associated with the activation of ERMs, including secretion from macrophages and platelets. It has previously been shown that the ability of the so-called mast cell "stabilizer" disodium cromoglycate (cromolyn) to inhibit secretion from rat mast cells closely paralleled the phosphorylation of a 78 kDa protein, which was subsequently shown to be moesin, a member of ERMs. Interestingly, the phosphorylation of moesin during the inhibition of mast cell secretion was on the N-terminal Ser56/74 and Thr66 residues. This phosphorylation pattern could lock moesin in its inactive state and render it inaccessible to binding to the Soluble NSF attachment protein receptors (SNAREs) and synaptosomal-associated proteins (SNAPs) critical for exocytosis. Using confocal microscopic imaging, we showed moesin was found to colocalize with actin and cluster around secretory granules during inhibition of secretion. In conclusion, the phosphorylation pattern and localization of moesin may be important in the regulation of mast cell secretion and could be targeted for the development of effective inhibitors of secretion of allergic and inflammatory mediators from mast cells.

On the complexity of IgE: The role of structural flexibility and glycosylation for binding its receptors

It is well established that immunoglobulin E (IgE) plays a crucial role in atopy by binding to two types of Fcε receptors (FcεRI and FcεRII, also known as CD23). The cross-linking of FcεRI-bound IgE on effector cells, such as basophils and mast cells, initiates the allergic response. Conversely, the binding of IgE to CD23 modulates IgE serum levels and antigen presentation. In addition to binding to FcεRs, IgE can also interact with other receptors, such as certain galectins and, in mice, some FcγRs. The binding strength of IgE to its receptors is affected by its valency and glycosylation. While FcεRI shows reduced binding to IgE immune complexes (IgE-ICs), the binding to CD23 is enhanced. There is no evidence that galectins bind IgE-ICs. On the other hand, IgE glycosylation plays a crucial role in the binding to FcεRI and galectins, whereas the binding to CD23 seems to be independent of glycosylation. In this review, we will focus on receptors that bind to IgE and examine how the glycosylation and complexation of IgE impact their binding.

Di-(2-ethylhexyl) phthalate aggravates fine particulate matter-induced asthma in weanling mice due to T follicular helper cell-dependent response

Environmental pollutants fine particulate matter and di-(2-ethylhexyl) phthalate (DEHP) are believed to be the risk factors for childhood asthma. Allergic asthma is basically an immediate hypersensitivity mediated by IgE, the product of humoral immune response. T follicular helper cells (Tfh) have been newly identified as the crucial T helper cells for supporting B cells to produce immunoglobulins in humoral immunity. Tfh cells are therefore potentially to serve as the diagnostic marker and therapeutic target of immune diseases. In this study, we examined the joint effects of fine particulate matter and DEHP on the initiation and progression of asthma and explored the fundamental role of Tfh cells during the process. Weanling C57BL/6 mice (both sexes) were concurrently exposed to DEHP (intragastric administration at 300 μg/kg) and fine atmospheric particulate matter (mean particle diameter < 4 µm, PM4) (oropharyngeal instillation at 2 mg/kg) once every three days for 30 days (10 times). We found that DEHP displayed adjuvant effects to potentiate PM4 allergen-induced expansion of Tfh and plasma cells, production of serum IgE and IgG1, and occurrence of airway hyper-responsiveness and inflammation. Then PM4 and DEHP co-exposure was performed to Cd4 knock-out mice reconstituted with normal wild-type adoptive Tfh cells or non-Tfh cells. The results of immune adoptive transfusion indicated that the joint immunotoxic effects of PM4 and DEHP were dependent on Tfh cells. We further proved that DEHP could adjuvantly boost PM4-induced expression of BCL-6 and c-MAF and secretion of IL-13 and IL-4 in Tfh cells. In conclusion, these data suggest that DEHP metabolites act in an adjuvant-like manner to aggravate PM4 allergen-induced asthma based on anaphylactic IgE response, resulting from excessive IL-13 and IL-4 synthesized by abnormally differentiated Tfh cells.

Advances in Current Drugs and Formulations for the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease with a complex pathophysiology. Treatment of AD remains challenging owing to the presence of a wide spectrum of clinical phenotypes and limited response to existing therapies. However, recent genetic, immunological, and pathophysiological insights into the disease mechanism resulted in the invention of novel therapeutic drug candidates. This review provides a comprehensive overview of current therapies and assesses various novel drug delivery strategies currently under clinical investigation. Further, this review majorly emphasizes on various topical treatments including emollient therapies, barrier repair agents, topical corticosteroids (TCS), phosphodiesterase 4 (PDE4) inhibitors, calcineurin inhibitors, and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway inhibitors. It also discusses biological and systemic therapies, upcoming treatments based on ongoing clinical trials. Additionally, this review scrutinized the use of pharmaceutical inactive ingredients in the approved topical dosage forms for AD treatment.

Human Monoclonal IgE Antibodies-a Major Milestone in Allergy

PURPOSE OF REVIEW

Bound to its high affinity receptor on mast cells and basophils, the IgE antibody molecule plays an integral role in the allergic reaction. Through interactions with the allergen, it provides the sensitivity and specificity parameters for cell activation and mediator release that produce allergic symptoms. Advancements in human hybridoma technologies allow for the generation and molecular definition of naturally occurring allergen-specific human IgE monoclonal antibodies.

RECENT FINDINGS

A high-resolution structure of dust mite allergen Der p 2 in complex with Fab of the human IgE mAb 2F10 was recently determined using X-ray crystallography. The structure reveals the fine molecular details of IgE 2F10 binding its 750 Å2 conformational epitope on Der p 2. This review provides an overview of this major milestone in allergy, the first atomic resolution structure of an authentic human IgE epitope. The molecular insights that IgE epitopes provide will allow for structure-based design approaches to the development of novel diagnostics, antibody therapeutics, and immunotherapies.

New Mechanistic Advances in FcεRI-Mast Cell-Mediated Allergic Signaling

Mast cells originate from the CD34⁺/CD117⁺ hematopoietic progenitors in the bone marrow, migrate into circulation, and ultimately mature and reside in peripheral tissues. Microbiota/metabolites and certain immune cells (e.g., Treg cells) play a key role in maintaining immune tolerance. Cross-linking of allergen-specific IgE on mast cells activates the high-affinity membrane-bound receptor FcεRI, thereby initiating an intracellular signal cascade, leading to degranulation and release of pro-inflammatory mediators. The intracellular signal transduction is intricately regulated by various kinases, transcription factors, and cytokines. Importantly, multiple signal components in the FcεRI-mast cell–mediated allergic cascade can be targeted for therapeutic purposes. Pharmacological interventions that include therapeutic antibodies against IgE, FcεRI, and cytokines as well as inhibitors/activators of several key intracellular signaling molecues have been used to inhibit allergic reactions. Other factors that are not part of the signal pathway but can enhance an individual’s susceptibility to allergen stimulation are referred to as cofactors. Herein, we provide a mechanistic overview of the FcεRI-mast cell–mediated allergic signaling. This will broaden our scope and visions on specific preventive and therapeutic strategies for the clinical management of mast cell–associated hypersensitivity reactions.

Immunoglobulin E-Dependent Activation of Immune Cells in Rhinovirus-Induced Asthma Exacerbation

Acute exacerbation is the major cause of asthma morbidity, mortality, and health-care costs. Respiratory viral infections, particularly rhinovirus (RV) infections, are associated with the majority of asthma exacerbations. The risk for bronchoconstriction with RV is associated with allergic sensitization and type 2 airway inflammation. The efficacy of the humanized anti-IgE monoclonal antibody omalizumab in treating asthma and reducing the frequency and severity of RV-induced asthma exacerbation is well-known. Despite these clinical data, mechanistic details of omalizumab's effects on RV-induced asthma exacerbation have not been well-defined for years due to the lack of appropriate animal models. In this Perspective, we discuss potential IgE-dependent roles of mast cells and dendritic cells in asthma exacerbations.

Nursing diagnoses in hospitalized patients with COVID-19 in Indonesia

Background

The COVID-19 pandemic has become a global public health issue, and the roles of nurses are very much needed in providing nursing services in the current situation. The enforcement of appropriate nursing diagnoses for patients with COVID-19 is also fundamental in determining proper nursing care to help the patients achieve maximum health.

Objective

This study aimed to describe and analyze nursing diagnoses in patients with COVID-19 treated in the isolation rooms and ICUs.

Methods

This study used a secondary data analysis from hospital medical record data of patients with COVID-19 from early December 2020 to the end of February 2021. Data were selected using a cluster random sampling technique and analyzed using descriptive statistics.

Results

The results showed that the signs and symptoms of the patients with COVID-19 that often appeared were fever, cough, shortness of breath, and decreased consciousness. The common nursing diagnoses in the hospitalized patients with COVID-19 were hyperthermia, ineffective airway clearance, gas exchange disorder, self-care deficit, spontaneous ventilation disorder, spontaneous circulation disorder, knowledge deficit, and shock risk.

Conclusion

This study offers an insight into nursing practices in the hospital setting, which can be used as a basis for nurses to perform complete nursing assessments and nursing diagnoses during the pandemic.

Mucosal Mast Cells as Key Effector Cells in Food Allergies

Mucosal mast cells (MMCs) localized in the intestinal mucosa play a key role in the development of IgE-mediated food allergies. Recent advances have revealed that MMCs are a distinctly different population from connective tissue mast cells localized in skin and other connective tissues. MMCs are inducible and transient cells that arise from bone marrow-derived mast cell progenitors, and their numbers increase rapidly during mucosal allergic inflammation. However, the mechanism of the dramatic expansion of MMCs and their cell functions are not well understood. Here, we review recent findings on the mechanisms of MMC differentiation and expansion, and we discuss the potential for the inducers of differentiation and expansion to serve as targets for food allergy therapy. In addition, we also discuss the mechanism by which oral immunotherapy, a promising treatment for food allergy patients, induces unresponsiveness to food allergens and the roles of MMCs in this process. Research focusing on MMCs should provide useful information for understanding the underlying mechanisms of food allergies in order to further advance the treatment of food allergies.

Impact of Anti-Type 2 Inflammation Biologic Therapy on COVID-19 Clinical Course and Outcome

SARS-CoV-2 pandemic had a general and deep impact on the clinical management of chronic diseases, including respiratory and allergic disorders. At the beginning of the pandemic, one of the main concerns was the potential impact of immunosuppressive/immunomodulatory drugs on COVID-19 clinical course. In this review, we aim to summarize and analyze the available clinical evidence from patients treated with anti-type 2 inflammation biologics (including anti-IgE, anti-IL-5 and anti-IL-4 agents), who developed COVID-19. Overall, the treatment with anti-Th2 biologics can be considered safe during COVID-19. It does not worsen the clinical course and outcome of COVID-19, and it may be actually protective somehow from developing severe forms. Moreover, patients treated with these biological agents do not seem to be more prone to get infected by SARS-CoV-2.

IgE and TGF-β Signaling: From Immune to Cardiac Remodeling

Cardiac remodeling is accompanied by cardiac hypertrophy, fibrosis, and dysfunction, eventually leading to heart failure (HF). However, the molecular mechanisms involved in cardiac remodeling are complicated, especially the association with immune. Immunoglobulin E (IgE) is a class of immunoglobulins involved in immune response to specific allergens. Recently, Zhao et al characterized a novel specific role of IgE and its high affinity receptor (FcεR1) in directly promoting pathological myocardial remodeling and cardiac dysfunction. Additionally, upon blocking IgE-FcεR1 signaling using FcεR1 genetic depletion or by administrating the anti-IgE monoclonal antibody omalizumab (Oma) in mice, they observed that cardiac hypertrophy and cardiac interstitial fibrosis induced by angiotensin II (Ang II) or transverse aortic constriction (TAC) were significantly suppressed. In contrast, IgE administration alone can aggravate pathological cardiac remodeling and dysfunction. RNA-seq and downstream analysis indicated that TGF-β was the common pathway and the most pivotal mediator in IgE-FcεR1-induced cardiac remodeling and dysfunction. Furthermore, the administration of a TGF-β inhibitor could ameliorate cardiac remodeling and improve cardiac function. Therefore, these findings suggest that IgE-FcεR1 maybe promising therapeutic targets for cardiac remodeling and provide an experimental basis for the use of omalizumab for HF patients combined with high serum IgE levels or allergic diseases.

Mastocytosis and Mast Cell Activation Disorders: Clearing the Air

Mast cells are derived from hematopoietic stem cell precursors and are essential to the genesis and manifestations of the allergic response. Activation of these cells by allergens leads to degranulation and elaboration of inflammatory mediators, responsible for regulating the acute dramatic inflammatory response seen. Mast cells have also been incriminated in such diverse disorders as malignancy, arthritis, coronary artery disease, and osteoporosis. There has been a recent explosion in our understanding of the mast cell and the associated clinical conditions that affect this cell type. Some mast cell disorders are associated with specific genetic mutations (such as the D816V gain-of-function mutation) with resultant clonal disease. Such disorders include cutaneous mastocytosis, systemic mastocytosis (SM), its variants (indolent/ISM, smoldering/SSM, aggressive systemic mastocytosis/ASM) and clonal (or monoclonal) mast cell activation disorders or syndromes (CMCAS/MMAS). Besides clonal mast cell activations disorders/CMCAS (also referred to as monoclonal mast cell activation syndromes/MMAS), mast cell activation can also occur secondary to allergic, inflammatory, or paraneoplastic disease. Some disorders are idiopathic as their molecular pathogenesis and evolution are unclear. A genetic disorder, referred to as hereditary alpha-tryptasemia (HαT) has also been described recently. This condition has been shown to be associated with increased severity of allergic and anaphylactic reactions and may interact variably with primary and secondary mast cell disease, resulting in complex combined disorders. The role of this review is to clarify the classification of mast cell disorders, point to molecular aspects of mast cell signaling, elucidate underlying genetic defects, and provide approaches to targeted therapies that may benefit such patients.