Allergy

Updates on Databases of Allergens and Allergen-Epitopes

The increasing prevalence of allergic diseases is of great public health concern. Environmental and food allergens are the major triggers of allergic diseases via respiratory or gastrointestinal routes, respectively. A major setback in the clinical management of allergies is the unavailability of purified allergens required for diagnostic purposes. Furthermore, manipulation of allergen sequences and structures by employing protein-engineering approaches is needed to design immunotherapeutic vaccines. All these approaches rely upon the sequence, structure, and epitope location of allergens. A number of databases have therefore been developed that serve as repositories of molecular information of allergens. In this chapter, we discuss the five most important widely used allergen databases that might be helpful for the research community working on molecular allergology.

Associations between Allergic and Autoimmune Diseases with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder within Families: A Population-Based Cohort Study

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are commonly comorbid with allergic and autoimmune diseases in children. The aim of the current study was to investigate the association between children’s and first-degree relatives’ (i.e., mother, father, and full sibling) allergic and autoimmune diseases and children’s ASD and ADHD. We enrolled participants from Taiwan’s Maternal and Child Health Database. We used the Cox regression model to examine the associations of familial, siblings’ and children’s allergic and autoimmune diseases with children’s ASD and/or ADHD. In total, we included 1,386,260 children in the current study. We found the significant association between familial allergic or autoimmune disease and development of ASD or ADHD among children. We also identified the predominant impact of familial aggregation on the above associations. The associations between some parental diagnoses of autoimmune or allergic diseases in children’s ASD and/or ADHD were stronger in mothers than those in fathers. Early assessment of the possibility of ASD and ADHD is required for children who have a parent with an allergic or autoimmune disease.

Engulfment of mast cell secretory granules on skin inflammation boosts dendritic cell migration and priming efficiency

BACKGROUND

Mast cells (MCs) are best known as key effector cells of allergic reactions, but they also play an important role in host defense against pathogens. Despite increasing evidence for a critical effect of MCs on adaptive immunity, the underlying mechanisms are poorly understood.

OBJECTIVE

Here we monitored MC intercellular communication with dendritic cells (DCs), MC activation, and degranulation and tracked the fate of exocytosed mast cell granules (MCGs) during skin inflammation.

METHODS

Using a strategy to stain intracellular MCGs in vivo, we tracked the MCG fate after skin inflammation-induced MC degranulation. Furthermore, exogenous MCGs were applied to MC-deficient mice by means of intradermal injection. MCG effects on DC functionality and adaptive immune responses in vivo were assessed by combining intravital multiphoton microscopy with flow cytometry and functional assays.

RESULTS

We demonstrate that dermal DCs engulf the intact granules exocytosed by MCs on skin inflammation. Subsequently, the engulfed MCGs are actively shuttled to skin-draining lymph nodes and finally degraded inside DCs within the lymphoid tissue. Most importantly, MCG uptake promotes DC maturation and migration to skin-draining lymph nodes, partially through MC-derived TNF, and boosts their T-cell priming efficiency. Surprisingly, exogenous MCGs alone are sufficient to induce a prominent DC activation and T-cell response.

CONCLUSION

Our study highlights a unique feature of peripheral MCs to affect lymphoid tissue-borne adaptive immunity over distance by modifying DC functionality through delivery of granule-stored mediators.

Inhibiting mast cell degranulation by HO-1 affects dendritic cell maturation in vitro

OBJECTIVE AND DESIGN

Mast cell (MC) degranulation can break peripheral immune tolerance. However, its mechanism remains unclear. Our goal was to study the stabilization of MC membranes by heme oxygenase-1 (HO-1) in order to influence dendritic cell (DC) function.

MATERIAL

Mast cells and dendritic cells were prepared from 8-week-old to 10-week-old C57BL/6 mice; spleen mononuclear cells (SMCs) were prepared from 8-week-old to 10-week-old C57BL/6 and Balb/c mice.

TREATMENT

Mast cells were pretreated with PBS, DMSO, Hemin (50 μl/ml), and Znpp (50 μl/ml) for 8 h.

METHOD

Real-time PCR and western-blot tested the HO-1 of MC mRNA and protein. The co-stimulatory molecules of DCs (CD80, CD86, CD40) were measured by flow cytometry, and levels of TNF-α, IL-6, and IFN-γ were measured by ELISA. We set up a one-way mixed lymphocyte reaction (MLR) model to test the proliferation of SMCs after MC/DC interaction. *P < 0.05 (t test) was taken as the level of statistical significance.

RESULT

MCs pretreated with hemin induced HO-1 mRNA and protein expression, then interacted with DCs; expression of the co-stimulatory molecules was attenuated. The TNF-α, IL-6, and IFN-γ levels in the co-culture system were decreased. These DCs couldn't stimulate the proliferation of SMCs.

CONCLUSION

Inhibiting MC degranulation by HO-1 restrained DC maturation and attenuated the proliferation of SMCs.

Allergen databases

In this chapter, five popular allergen databases have been described: (1) Allergome is based on basic and clinical information on allergens causing an IgE-mediated disease; (2) AllergenOnline allows online search of peer-reviewed allergen list; (3) International Union of Immunological Societies Allergen nomenclature subcommittee database contains systematic nomenclature and molecular details of well-characterized allergens; (4) AllFam allows classifying allergens into protein families based on domain information; and (5) SDAP provides in detail structural information of the allergens.

Anti-apoptotic BFL-1 is the major effector in activation-induced human mast cell survival

Mast cells are best known for their role in allergic reactions, where aggregation of FcεRI leads to the release of mast cell mediators causing allergic symptoms. The activation also induces a survival program in the cells, i.e., activation-induced mast cell survival. The aim of the present study was to investigate how the activation-induced survival is mediated. Cord blood-derived mast cells and the mast cell line LAD-2 were activated through FcεRI crosslinking, with or without addition of chemicals that inhibit the activity or expression of selected Bcl-2 family members (ABT-737; roscovitine). Cell viability was assessed using staining and flow cytometry. The expression and function of Bcl-2 family members BFL-1 and MCL-1 were investigated using real-time quantitative PCR and siRNA treatment. The mast cell expression of Bfl-1 was investigated in skin biopsies. FcεRI crosslinking promotes activation-induced survival of human mast cells and this is associated with an upregulation of the anti-apoptotic Bcl-2 family member Bfl-1. ABT-737 alone or in combination with roscovitine decreases viability of human mast cells although activation-induced survival is sustained, indicating a minor role for Bcl-X(L), Bcl-2, Bcl-w and Mcl-1. Reducing BFL-1 but not MCL-1 levels by siRNA inhibited activation-induced mast cell survival. We also demonstrate that mast cell expression of Bfl-1 is elevated in birch-pollen-provocated skin and in lesions of atopic dermatitis and psoriasis patients. Taken together, our results highlight Bfl-1 as a major effector in activation-induced human mast cell survival.

Potential role of antioxidant food supplements, preservatives and colorants in the pathogenesis of allergy and asthma

A significant increase in the incidence of allergy and asthma has been observed during the past decades. The background of this phenomenon has not been well explained, but changes in lifestyle and habits are heavily discussed as contributing factors. Among these is a too clean environment, which may predispose individuals to increased sensitivity to allergic responses. Also the increase in dietary supplements including preservatives and colorants may contribute to this. In vitro, we and others have shown in freshly isolated human peripheral blood mononuclear cells that antioxidant compounds like vitamins C and E as well as food preservatives and colorants exert significant suppressive effects on the Th1 immune activation cascade. The effects observed may be based on the interaction of antioxidant compounds with proinflammatory cascades involving important signal transduction elements such as nuclear factor-κB. Although only obtained in vitro, these results show an anti-inflammatory property of compounds which could shift the Th1-Th2-type immune balance towards Th2-type immunity. This review article discusses the potential role of increased use of antioxidant food supplements as well as preservatives and colorants in the increase in allergy and asthma in the Western world.

Mast cells augment adaptive immunity by orchestrating dendritic cell trafficking through infected tissues

Mast cells (MCs) are best known for eliciting harmful reactions, mostly after primary immunity has been established. Here, we report that, during footpad infection with E. coli in MC-deficient mice, as compared to their MC-sufficient counterparts, the serum antibody response is significantly diminished and less protective following passive immunization in a urinary tract infection (UTI) model in wild-type mice. MCs were found to recruit large numbers of dendritic cells (DCs) into the infected tissue site, which eventually migrated into draining lymph nodes (DLNs) during a prolonged time course. This pattern of trafficking was facilitated by MC-generated TNF, which increased the expression of E-selectin on local blood vessels. Antibody blockade of E-selectin inhibited DC recruitment into the site of infection and DLNs and consequently impaired the primary humoral immune response. Thus, during infection, resident MCs contribute to the primary protective adaptive response through recruitment of DCs from the circulation into infected sites.

Essential role of the prosurvival bcl-2 homologue A1 in mast cell survival after allergic activation

Mast cells reside in tissues, where upon activation through the high-affinity-IgE-receptor (FcepsilonRI) they degranulate and orchestrate the allergic reaction. Mast cells survive this activation and can thus be reactivated. In this study we demonstrate that this process depends on the pro-survival gene A1. Activation of mast cells through FcepsilonRI resulted in degranulation, strong induction of A1 mRNA and protein, and cell survival. In contrast, A1-deficient mast cells released granule mediators similar to the wild-type control, but the cells did not survive an allergic activation. Furthermore, A1(-/-) mice that had been sensitized and provoked with allergen exhibited a lower number of mast cell compared with littermate controls. The induction of A1 was dependent on calcium, as EDTA prevented A1 expression. The calcium ionophore, ionomycin, induced A1 expression and mast cell survival, whereas compound 48/80, a well-known mast cell secretagogue, did not. This study uncovers the importance of A1 for mast cell survival in allergic reactions, and it proposes A1 as a potential target for the treatment of allergic diseases.