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Frontiers in Pharmacology 2024Fexofenadine (FEX) is an antihistamine that acts as an inverse agonist against histamine (HIS) receptor 1 (H1R), which mediates the allergic reaction. Inverse agonists...
Establishment of a human nasal epithelium model of histamine-induced inflammation to assess the activity of fexofenadine as an inverse agonist and its link to clinical benefit.
BACKGROUND
Fexofenadine (FEX) is an antihistamine that acts as an inverse agonist against histamine (HIS) receptor 1 (H1R), which mediates the allergic reaction. Inverse agonists may be more potent than neutral antagonists, as they bind the same receptor as the agonist (HIS) but stabilize the inactive form and induce an opposite pharmacological response, suppressing the basal activity of H1R and preventing HIS from binding. This study aims to establish and validate a model of HIS-induced inflammation based on fully reconstituted human nasal epithelial tissue to assess the activity of FEX as an inverse agonist in this model and explore its link to clinical benefit.
METHODS
The model was developed using nasal MucilAir™ (Epithelix) epithelium challenged by HIS. Two conditions were assessed in a side-by-side comparison: tissue was exposed to HIS + FEX with or without FEX pre-treatment (one-hour prior to HIS challenge). Tissue functionality, cytotoxicity, H1R gene expression, and inflammatory cytokines were assessed.
RESULTS
HIS at 100 µM induced significant 3.1-fold and 2.2-fold increases for inflammatory biomarkers interleukin (IL)-8 and IL-6, respectively ( < 0.0001), as well as rapid upregulation of H1R mRNA. Inflammatory biomarkers were inhibited by FEX and H1R expression was significantly reduced ( < 0.0001). FEX alone decreased H1R expression at all doses tested. With one-hour FEX pre-treatment, there was significantly higher downregulation of IL-8 ( < 0.05) and further downregulation of H1R expression and IL-6 without FEX pre-treatment; the effects of FEX were improved from 22% to 40%.
CONCLUSION
A model of HIS-induced airway inflammation was established based on IL-8, IL-6 and H1R gene expression and was validated with FEX. FEX works as an inverse agonist, with a higher effect when used before+during only during the HIS challenge. Taking FEX before+during allergen exposure, or when symptoms first occur, may reduce basal activity and H1R gene expression, providing stronger protection against the worsening of symptoms upon allergen exposure.
PubMed: 38933682
DOI: 10.3389/fphar.2024.1393702 -
Frontiers in Immunology 2024Allergic sensitization is an essential step in the development of allergic airway inflammation to birch pollen (BP); however, this process remains to be fully...
INTRODUCTION & OBJECTIVE
Allergic sensitization is an essential step in the development of allergic airway inflammation to birch pollen (BP); however, this process remains to be fully elucidated. Recent scientific advances have highlighted the importance of the allergen context. In this regard, microbial patterns (PAMPs) present on BP have attracted increasing interest. As these PAMPs are recognized by specialized pattern recognition receptors (PRRs), this study aims at investigating the roles of intracellular PRRs and the inflammasome regulator NLRP3.
METHODS
We established a physiologically relevant intranasal and adjuvant-free sensitization procedure to study BP-induced systemic and local lung inflammation.
RESULTS
Strikingly, BP-sensitized -deficient mice showed significantly lower IgE levels, Th2-associated cytokines, cell infiltration into the lung, mucin production and epithelial thickening than their wild-type counterparts, which appears to be independent of inflammasome formation. Intriguingly, bone-marrow chimera revealed that expression of NLRP3 in the hematopoietic system is required to trigger an allergic response.
CONCLUSION
Overall, this study identifies NLRP3 as an important driver of BP-induced allergic immune responses.
Topics: Animals; NLR Family, Pyrin Domain-Containing 3 Protein; Pollen; Betula; Mice; Mice, Knockout; Administration, Intranasal; Allergens; Disease Models, Animal; Inflammasomes; Mice, Inbred C57BL; Cytokines; Hypersensitivity; Plant Extracts; Immunoglobulin E
PubMed: 38933263
DOI: 10.3389/fimmu.2024.1393819 -
Fundamental Research May 2024Bioaerosols are a subset of important airborne particulates that present a substantial human health hazard due to their allergenicity and infectivity. Chemical reactions... (Review)
Review
Bioaerosols are a subset of important airborne particulates that present a substantial human health hazard due to their allergenicity and infectivity. Chemical reactions in atmospheric processes can significantly influence the health hazard presented by bioaerosols; however, few studies have summarized such alterations to bioaerosols and the mechanisms involved. In this paper, we systematically review the chemical modifications of bioaerosols and the impact on their health effects, mainly focusing on the exacerbation of allergic diseases such as asthma, rhinitis, and bronchitis. Oxidation, nitration, and oligomerization induced by hydroxyl radicals, ozone, and nitrogen dioxide are the major chemical modifications affecting bioaerosols, all of which can aggravate allergenicity mainly through immunoglobulin E pathways. Such processes can even interact with climate change including the greenhouse effect, suggesting the importance of bioaerosols in the future implementation of carbon neutralization strategies. In summary, the chemical modification of bioaerosols and the subsequent impact on health hazards indicate that the combined management of both chemical and biological components is required to mitigate the health hazards of particulate air pollution.
PubMed: 38933216
DOI: 10.1016/j.fmre.2023.10.017 -
Vaccines Jun 2024Currently, allergen-specific immunotherapy (AIT) for ragweed allergy is still based on natural allergen extracts. This study aimed to analyse the ability of four...
Currently, allergen-specific immunotherapy (AIT) for ragweed allergy is still based on natural allergen extracts. This study aimed to analyse the ability of four commercially available AIT vaccines (CLUSTOID, TYRO-SIT, POLLINEX Quattro Plus and Diater Depot) regarding their ability to induce IgG antibodies against ragweed pollen allergens in rabbits. Accordingly, the IgG reactivity of AIT-induced rabbit sera was tested for ten different ragweed pollen allergens (Amb a 1, 3, 4, 5, 6, 8, 9, 10, 11 and 12) by an ELISA. Furthermore, the ability of rabbit AIT-specific sera to block allergic patients' IgE binding to relevant ragweed allergens (Amb a 1, 4, 6, 8 and 11) and to inhibit allergen-induced basophil activation was evaluated by an IgE inhibition ELISA and a mediator release assay. Only two AIT vaccines (Diater Depot > CLUSTOID) induced relevant IgG antibody levels to the major ragweed allergen Amb a 1. The IgG responses induced by the AIT vaccines against the other ragweed allergens were low and highly heterogeneous. Interestingly, the kinetics of IgG responses were different among the AIT vaccines and even within one AIT vaccine (Diater Depot) for Amb a 1 (long-lasting) versus Amb a 8 and Amb a 11 (short-lived). This could be due to variations in allergen contents, the immunogenicity of the allergens, and different immunization protocols. The IgE inhibition experiments showed that rabbit AIT-specific sera containing high allergen-specific IgG levels were able to inhibit patients' IgE binding and prevent the mediator release with Diater Depot. The high levels of allergen-specific IgG levels were associated with their ability to prevent the recognition of allergens by patients' IgE and allergen-induced basophil activation, indicating that the measurement of allergen-induced IgG could be a useful surrogate marker for the immunological efficacy of vaccines. Accordingly, the results of our study may be helpful for the selection of personalized AIT vaccination strategies for ragweed-allergic patients.
PubMed: 38932364
DOI: 10.3390/vaccines12060635 -
Vaccines Jun 2024Canine atopic dermatitis (CAD) is an allergic, inflammatory, and pruritic skin disease associated with the production of IgE antibodies against environmental allergens...
Canine atopic dermatitis (CAD) is an allergic, inflammatory, and pruritic skin disease associated with the production of IgE antibodies against environmental allergens and mainly house dust mite allergens. This complex dermatological pathology involves Interleukin 31 (IL-31) as a central itch mediator. One of the most effective CAD treatments is a caninized monoclonal antibody (mAb) called Lokivetmab. It is produced in CHO cells and targets specifically canine IL-31 (cIL-31) and blocks its cellular messaging. This treatment has undoubtedly contributed to a breakthrough in dermatitis-related pruritus. However, its production in mammalian cells requires time-consuming procedures, high production costs, and investment. Plants are considered an emerging protein production platform for recombinant biopharmaceuticals due to their cost-effectiveness and rapidity for production. Here, we use transient expression in plants to produce recombinant canine Interleukin 31 (cIL-31) and an anti-IL-31 monoclonal antibody (M1). First, we describe the production and characterization of M1 and then its activity on an IL-31-induced pruritic model in dogs compared to its commercial homolog. Dogs treated with the plant-made M1 mAb have shown similar improvements to Lokivetmab-treated ones after different challenges using canine IL-31. Furthermore, M1 injections were not associated with any side effects. These results demonstrate the safety and efficacy of this plant-made Lokivetmab biosimilar to control dogs' pruritus in a well-established model. Finally, this study shows that the plant-production platform can be utilized to produce rapidly functional mAbs and bring hope to the immunotherapy field of veterinary medicine.
PubMed: 38932349
DOI: 10.3390/vaccines12060620 -
Sensors (Basel, Switzerland) Jun 2024As a growing part of the world population is suffering from pollen-induced allergies, increasing the number of pollen monitoring stations and developing new dedicated...
As a growing part of the world population is suffering from pollen-induced allergies, increasing the number of pollen monitoring stations and developing new dedicated measurement networks has become a necessity. To this purpose, Beenose, a new automatic and relatively low-cost sensor, was developed to characterize and quantify the pollinic content of the air using multiangle light scattering. A field campaign was conducted at four locations around Brussels, Belgium, during summer 2022 and winter-spring 2023. First, the consistency was assessed between the automatic sensor and a collocated reference Hirst-type trap deployed at Ixelles, south-east of Brussels. Daily average total pollen concentrations provided by the two instruments showed a mean error of about 15%. Daily average pollen concentrations were also checked for a selection of pollen species and revealed Pearson and Spearman correlation coefficients ranging from 0.71 to 0.93. Subsequently, a study on the spatial variability of the pollen content around Brussels was conducted with Beenose sensors. The temporal evolution of daily average total pollen concentrations recorded at four sites were compared and showed strong variations from one location to another, up to a factor 10 over no more than a few kilometers apart. This variation is a consequence of multiple factors such as the local vegetation, the wind directions, the altitude of the measurement station, and the topology of the city. It is therefore highly necessary to multiply the number of measurement stations per city for a better evaluation of human exposure to pollen allergens and for more enhanced pollen allergy management.
Topics: Pollen; Belgium; Environmental Monitoring; Allergens; Seasons; Humans; Air Pollutants; Cities
PubMed: 38931513
DOI: 10.3390/s24123731 -
Pharmaceuticals (Basel, Switzerland) May 2024Given the ongoing rise in the occurrence of allergic disorders, alterations in dietary patterns have been proposed as a possible factor contributing to the emergence and... (Review)
Review
Given the ongoing rise in the occurrence of allergic disorders, alterations in dietary patterns have been proposed as a possible factor contributing to the emergence and progression of these conditions. Currently, there is a significant focus on the development of dietary therapies that utilize natural compounds possessing anti-allergy properties. Dietary polyphenols and plant metabolites have been intensively researched due to their well-documented anti-inflammatory, antioxidant, and immunomodulatory characteristics, making them one of the most prominent natural bioactive chemicals. This study seeks to discuss the in-depth mechanisms by which these molecules may exert anti-allergic effects, namely through their capacity to diminish the allergenicity of proteins, modulate immune responses, and modify the composition of the gut microbiota. However, further investigation is required to fully understand these effects. This paper examines the existing evidence from experimental and clinical studies that supports the idea that different polyphenols, such as catechins, resveratrol, curcumin, quercetin, and others, can reduce allergic inflammation, relieve symptoms of food allergy, asthma, atopic dermatitis, and allergic rhinitis, and prevent the progression of the allergic immune response. In summary, dietary polyphenols and plant metabolites possess significant anti-allergic properties and can be utilized for developing both preventative and therapeutic strategies for targeting allergic conditions. The paper also discusses the constraints in investigating and broad usage of polyphenols, as well as potential avenues for future research.
PubMed: 38931338
DOI: 10.3390/ph17060670 -
Molecules (Basel, Switzerland) Jun 2024Antibodies are widely used in medicinal and scientific research due to their ability to bind to a specific antigen. Most often, antibodies are composed of heavy and...
Antibodies are widely used in medicinal and scientific research due to their ability to bind to a specific antigen. Most often, antibodies are composed of heavy and light chain domains. Under physiological conditions, light chains are produced in excess, as compared to the heavy chain. It is now known that light chains are not silent partners of the heavy chain and can modulate the immune response independently. In this work, the first crystal structure of a light chain dimer originating from mice is described. It represents the light chain dimer of 6A8, a monoclonal antibody specific to the allergen Der f 1. Building on the unexpected occurrence of this kind of dimer, we have demonstrated that this light chain is stable in solution alone. Moreover, enzyme-linked immunosorbent assays (ELISA) have revealed that, when the light chain is not partnered to its corresponding heavy chain, it interacts non-specifically with a wide range of proteins. Computational studies were used to provide insight on the role of the 6A8 heavy chain domain in the specific binding to Der f 1. Overall, this work demonstrates and supports the ongoing notion that light chains can function by themselves and are not silent partners of heavy chains.
Topics: Animals; Mice; Immunoglobulin Light Chains; Protein Multimerization; Antibodies, Monoclonal; Models, Molecular; Protein Binding; Crystallography, X-Ray; Protein Conformation; Immunoglobulin Heavy Chains
PubMed: 38930950
DOI: 10.3390/molecules29122885 -
Journal of Clinical Medicine Jun 2024Severe asthma often remains uncontrolled despite optimized inhaled treatment. The rise of biologic therapy in severe asthma represented a major advance for the disease...
Severe asthma often remains uncontrolled despite optimized inhaled treatment. The rise of biologic therapy in severe asthma represented a major advance for the disease management. However, correct phenotyping and monitoring of severe asthma patients is key to the success of targeted biologic therapy. We present the case of a 63-year-old female, never a smoker, diagnosed with asthma at the age of 45 and associated persistent mild rhinitis, without other notable comorbidities. She was prescribed medium-dose ICS/LABA, administered inconstantly in the first years after the diagnosis, with poor overall control of the disease. After several exacerbation episodes, treatment compliance improved, but the control of the disease remained poor despite adding an antileukotriene. In January 2019, she presented an exacerbation episode requiring treatment with oral corticosteroids (OCS) and she was afterwards put on high-dose ICS/LABA and continued the antileukotriene. She was referred for a skin allergy test, which revealed mild sensitization to Dermatophagoides pteronyssinus and farinae, with a total IgE level of 48.3 IU/mL. The blood eosinophil level was 270 cells/mm. The lung function was variable, going from mild impairment to severe fixed obstruction during exacerbations. Despite optimized inhaled treatment, good adherence and inhaler technique, and allergen avoidance strategies, asthma control was not achieved, and she continued to experience severe episodes of exacerbation requiring OCS. In October 2019, she was initiated on biologic therapy with omalizumab, which allowed asthma control to be achieved and maintained for 18 months, with preserved lung function, good symptom control, no exacerbations and slightly elevated blood eosinophil level (340-360 cells/mm). In April 2021, she started experiencing exacerbation episodes requiring OCS (three episodes within 6 months), with a progressive increase in blood eosinophil level (up to 710 cells/mm), and progressive deterioration of asthma control and lung function, despite continuation of previous therapy. A specific IgE test against Aspergillus was negative, and total IgE level was 122.4 IU/mL. In December 2021, the patient was switched from omalizumab to benralizumab. Asthma control was again achieved, lung function improved significantly and the patient did not experience any other exacerbation episodes up until today, which allowed for a reduction in ICS dose. Intriguingly, a relapsing eosinophilia was also noted under anti-IL5-R treatment prior to the dose administration, but with preserved asthma control. This case underscores the pivotal role of meticulous phenotyping in severe asthma management on one side, and careful monitoring of patient evolution and possible side effects of treatment on the other side. By showcasing how diverse inflammatory pathways can coexist within a single patient and impact treatment outcomes, it highlights the necessity of tailored biologic therapy for sustained control.
PubMed: 38929930
DOI: 10.3390/jcm13123402 -
Life (Basel, Switzerland) May 2024Allergic conjunctivitis is an allergen-induced immune response secondary to the binding of immunoglobulin-E (IgE) to sensitized mast cells. Approximately 40% of North... (Review)
Review
Allergic conjunctivitis is an allergen-induced immune response secondary to the binding of immunoglobulin-E (IgE) to sensitized mast cells. Approximately 40% of North Americans and 20% of the world's population are impacted by some form of allergy and it continues to increase in prevalence, especially among children. Specified IgE antibodies can be found in almost all cases of exposure to seasonal or perennial allergens. Activation and degranulation of mast cells lead to increased tear levels of histamine, tryptase, leukotrienes, cytokines, and prostaglandins. The release of these factors initiates the recruitment of inflammatory cells in the conjunctival mucosa, which causes the late-phase reaction. Signs and symptoms of ocular allergies include itching, tearing, chemosis, and hyperemia, which can lead to decreased productivity and poor quality of life. Many treatment options are available to improve symptoms, including, mast cell stabilizers, antihistamines, dual-acting agents, steroids, nonsteroidal anti-inflammatory drugs (NSAIDS), and other off-label treatment modalities. This review article provides an overview of different types of allergic conjunctivitis, its pathology and immunology, and recommended methods of treatment.
PubMed: 38929634
DOI: 10.3390/life14060650