RESUMEN
Immunoglobulin E (IgE)-mediated food allergy is a rapidly growing public health problem. The interaction between allergens and IgE is at the core of the allergic response. One of the best ways to understand this interaction is through structural characterization. This review focuses on animal-derived food allergens, overviews allergen structures determined by X-ray crystallography, presents an update on IgE conformational epitopes, and explores the structural features of these epitopes. The structural determinants of allergenicity and cross-reactivity are also discussed. Animal-derived food allergens are classified into limited protein families according to structural features, with the calcium-binding protein and actin-binding protein families dominating. Progress in epitope characterization has provided useful information on the structural properties of the IgE recognition region. The data reveals that epitopes are located in relatively protruding areas with negative surface electrostatic potential. Ligand binding and disulfide bonds are two intrinsic characteristics that influence protein structure and impact allergenicity. Shared structures, local motifs, and shared epitopes are factors that lead to cross-reactivity. The structural properties of epitope regions and structural determinants of allergenicity and cross-reactivity may provide directions for the prevention, diagnosis, and treatment of food allergies. Experimentally determined structure, especially that of antigen-antibody complexes, remains limited, and the identification of epitopes continues to be a bottleneck in the study of animal-derived food allergens. A combination of traditional immunological techniques and emerging bioinformatics technology will revolutionize how protein interactions are characterized.
Asunto(s)
Alérgenos , Epítopos , Hipersensibilidad a los Alimentos , Inmunoglobulina E , Alérgenos/química , Alérgenos/inmunología , Hipersensibilidad a los Alimentos/inmunología , Epítopos/química , Epítopos/inmunología , Animales , Cristalografía por Rayos X , Humanos , Inmunoglobulina E/inmunología , Inmunoglobulina E/química , Reacciones Cruzadas , Conformación ProteicaRESUMEN
Ovomucoid is the immune-dominant allergen in the egg white of hens. Due to its structure based on nine disulfide bonds as well as its resistance to heat and enzymatic hydrolysis, the allergenicity of this food protein is difficult to decrease by technological processes. We sought to reduce its allergenicity through the Maillard reaction. The unfolding of ovomucoid with L-cysteine-mediated reduction was used to increase accessibility to conformational and linear epitopes by modifying the secondary and tertiary structures of the allergen. Glycation with different saccharides revealed the beneficial effect of maltose glycation on the IgG-binding capacity reduction. By determining the better glycation conditions of unfolded ovomucoid, we produced ovomucoid with reduced IgE binding capacity due to the glycation sites (K17, K112, K129, and K164) on epitopes. Moreover, after simulated infant and adult gastrointestinal digestion, the unfolded plus glycated ovomucoid showed higher ABTSË+ scavenging activity, O2Ë- scavenging activity, ËOH scavenging activity, Fe2+ chelating activity, and a FRAP value; in particular, for ËOH scavenging activity, there was a sharp increase of more than 100%.
Asunto(s)
Reacción de Maillard , Ovomucina , Humanos , Lactante , Adulto , Animales , Femenino , Ovomucina/química , Ovomucina/metabolismo , Antioxidantes , Pollos/metabolismo , Epítopos/química , Alérgenos/química , Inmunoglobulina E/química , Inmunoglobulina G/químicaRESUMEN
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.
Asunto(s)
Anafilaxia , Antialérgicos , Diterpenos , Hipersensibilidad , Humanos , Antialérgicos/farmacología , Antialérgicos/uso terapéutico , Receptores de IgE/química , Receptores de IgE/metabolismo , Receptores de IgE/uso terapéutico , Inmunoglobulina E/química , Inmunoglobulina E/metabolismo , Inmunoglobulina E/uso terapéutico , Inmunoinformática , Estudios Prospectivos , Hipersensibilidad/tratamiento farmacológico , Hipersensibilidad/metabolismo , Anafilaxia/tratamiento farmacológico , Anafilaxia/prevención & controlRESUMEN
Allergic diseases are a global public health problem that affects up to 30% of the population in industrialized societies. More than 40% of allergic patients suffer from grass pollen allergy. Grass pollen allergens of group 1 and group 5 are the major allergens, since they induce allergic reactions in patients at high rates. In this study, we used immunoinformatic approaches to design an effective epitope-based vaccine against the grass group 1 allergens. After the alignment of all known pollen T-cell and B-cell epitopes from pollen allergens available in the public databases, the epitope GTKSEVEDVIPEGWKADTSY was identified as the most suitable for further analyses. The target sequence was subjected to immunoinformatics analyses to predict antigenic T-cell and B-cell epitopes. Population coverage analysis was performed for CD8+ and CD4+ T-cell epitopes. The selected T-cell epitopes (VEDVIPEGW and TKSEVEDVIPEGWKA) covered 78.87% and 98.20% of the global population and 84.57% and 99.86% of the population of Europe. Selected CD8+, CD4+ T-cell and B-cell epitopes have been validated by molecular docking analysis. CD8+ and CD4+ T-cell epitopes showed a very strong binding affinity to major histocompatibility complex (MHC) class I (MHC I) molecules and MHC class II (MHC II) molecules with global energy scores of -72.1 kcal/mol and -89.59 kcal/mol, respectively. The human IgE-Fc (PDB ID 4J4P) showed a lower affinity with B-cell epitope (ΔG = -34.4 kcal/mol), while the Phl p 2-specific human IgE Fab (PDB ID 2VXQ) had the lowest binding with the B-cell epitope (ΔG = -29.9 kcal/mol). Our immunoinformatics results demonstrated that the peptide GTKSEVEDVIPEGWKADTSY could stimulate the immune system and we performed ex vivo tests showed that the investigated epitope activates T cells isolated from patients with grass pollen allergy, but it is not recognized by IgE antibodies specific for grass pollen allergens. This confirms the importance of such studies to establish universal epitopes to serve as a basis for developing an effective vaccine against a particular group of allergens. Further in vivo studies are needed to validate the effectiveness of such a vaccine against grass pollen allergens.
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Hipersensibilidad , Rinitis Alérgica Estacional , Vacunas , Humanos , Alérgenos , Poaceae/química , Poaceae/metabolismo , Epítopos de Linfocito B/química , Rinitis Alérgica Estacional/prevención & control , Epítopos de Linfocito T , Simulación del Acoplamiento Molecular , Secuencia de Aminoácidos , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Inmunoglobulina E/química , Inmunoglobulina E/metabolismoRESUMEN
Tropomyosin (TM) is a major crustacean allergen, and the present studies have tried to reduce its allergenicity by processing technologies. However, most research stopped on the allergenicity and structure of allergens, while information about epitopes was less. In this study, we first investigated the effects of cold plasma (CP) combined with glycation (CP-G) treatment on the processing and trypsin cleavage sites of TM from shrimp (Penaeus chinensis). The results showed a significant reduction in the IgE-binding capacity of TM after CP-G treatment, with a maximum reduction of 30%. This reduction was associated with the combined effects: modification induced by CP destroyed the core helical structure (D137 and E218) and occupied the potential glycation sites, leading to sequent glycation on conserved areas of TM, especially the epitope L130-Q147. Additionally, CP-G treatment decreased the digestion stability of TM by increasing the number of cleavage sites of trypsin and improving the efficiency of some sites, including K5, K6, K30, and R133, resulting in a lower IgE-binding capacity of digestion products, which fell to a maximum of 20%. Thus, CP-G is a valuable and reliable processing technology for the desensitization of aquatic products.
Asunto(s)
Penaeidae , Gases em Plasma , Animales , Tropomiosina/química , Reacción de Maillard , Tripsina , Alérgenos/química , Penaeidae/química , Inmunoglobulina E/química , Epítopos/química , DigestiónRESUMEN
Atopic dermatitis (AD) is a common pruritic inflammatory skin disease with complex environmental and genetic predisposing factors. Primary skin barrier dysfunction and aberrant T helper 2 (TH2) responses to common allergens, together with increased serum IgE antibodies, characterise the disease. B and T cells are essential in the disease manifestation, however, the exact mechanism of how these cells is involved is unclear. Targeting interleukin 4 receptor alpha (IL-4Rα), an IL-4/IL-13 signalling axis, with dupilumab shows efficacy in AD. We investigated the importance of IL-4Rα signalling specifically on B and T cells during acute and chronic models of AD. We used House dust mite (HDM) and Ovalbumin (OVA) in chronic models and a low-calcemic analog of vitamin D (MC903) for acute models of AD. We used mb1creIL-4Rα-/lox, iLCKcreIL-4Rα-/lox, LCKcreIL-4Rα-/lox, CD4creIL-4Rα-/lox, Foxp3creIL-4Rα-/lox and IL-4Rα-/lox littermate controls. IL-4Rα-responsive B cells were essential in serum IgE levels, but not in epidermal thickening in both chronic and acute models. IL-4Rα-responsive T cells were essential in epidermal thickening in the pan-T cell, but not CD4 or CD8 T cells suggesting the importance of γδT cells during acute AD. Our results suggest that IL-4Rα responsiveness on innate T cells regulates acute atopic dermatitis, while on B cells it regulates IgE.
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Linfocitos B , Dermatitis Atópica , Subunidad alfa del Receptor de Interleucina-4 , Células Th2 , Animales , Ratones , Alérgenos/efectos adversos , Linfocitos B/metabolismo , Linfocitos B/patología , Dermatitis Atópica/metabolismo , Dermatitis Atópica/patología , Inmunoglobulina E/sangre , Inmunoglobulina E/química , Subunidad alfa del Receptor de Interleucina-4/metabolismo , Ratones Endogámicos BALB C , Ratones Noqueados , Receptores de Interleucina-4/metabolismo , Células Th2/metabolismo , Células Th2/patologíaRESUMEN
Structural and functional information about food allergens is essential for understanding the allergenicity of food proteins. All allergens belong to a small number of protein families. Various allergens from different families have been successfully produced recombinantly in E. coli for their characterization and applications in allergy diagnosis and treatment. However, recombinant hexameric 11S seed storage protein has not been reported, although numerous 11S legumins are known to be food allergens, including the recently identified macadamia nut allergen Mac i 2. Here we report the production of a macadamia nut legumin by expressing it in E. coli with a substrate site of HRV 3C protease and cleaving the purified protein with HRV 3C protease. The protease divided the protein into two chains and left a native terminus for the C-terminal chain, resulting in a recombinant hexameric 11S allergen for the first time after the residues upstream to the cleavage site flipped out of the way of the trimer-trimer interaction. The 11S allergens are known to have multiple isoforms in many species. The present study removed an obstacle in obtaining homogeneous allergens needed for studying allergens and mitigating allergenicity. Immunoreactivity of the protein with serum IgE confirmed it to be a new isoform of Mac i 2.
Asunto(s)
Alérgenos , Antígenos de Plantas , Hipersensibilidad a la Nuez , Humanos , Alérgenos/química , Antígenos de Plantas/química , Antígenos de Plantas/genética , Escherichia coli/genética , Inmunoglobulina E/química , Macadamia/genética , Hipersensibilidad a la Nuez/diagnóstico , Hipersensibilidad a la Nuez/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/química , Isoformas de Proteínas , LeguminasRESUMEN
Ovalbumin (OVA), the major component of egg white, has been used as a model carrier protein to study the interaction of four bioactive phytochemicals 6-hydroxyflavone, chrysin, naringin, and naringenin. A static quenching mechanism was primarily associated with the complexation of the flavonoids with OVA. Hydrophobic forces play a major part in the stability of the complexes. The structural changes within the protein in response to flavonoid binding revealed a decrease in OVA's α-helical content. The hypothesized binding site for flavonoids in OVA overlaps with one or more immunoglobulin E-binding epitopes that may have some effect in the immunoglobulin E response pathway. The flavonoids remain in the same binding site throughout the simulation time and impart protein stability by forming different noncovalent interactions. This study presents comprehensive information about the interaction of the flavonoids with OVA and the associated structural variations after the binding, which might help researchers better comprehend similar medication pharmacodynamics and provide critical information for future therapeutic development.
Asunto(s)
Hipersensibilidad al Huevo , Clara de Huevo , Humanos , Ovalbúmina/química , Ovalbúmina/metabolismo , Inmunoglobulina E/química , Inmunoglobulina E/metabolismo , Alérgenos/química , Unión Proteica , Simulación del Acoplamiento MolecularRESUMEN
BACKGROUND: Dust mite extract contains multiple components that, while useful in clinical allergy diagnosis and treatment, can cause serious side effects. Defining components of dust mite extract is important their contributions to allergic disease. This study aimed to characterize a novel dust mite allergen, Der p 22. METHODS: We amplified the cDNA encoding Der p 22 from total RNA of the mite Dermatophagoides pteronyssinus, and inserted it into an expression construct for transformation to competent cells. Purified recombinant (r) Der p 22 was tested for IgE-binding reactivity in sera obtained from children with allergic asthma by the Affiliated Wuxi Children's Hospital of Nanjing Medical University (Jiangsu, China). rDer p 22 also was used to challenge BALB/c mice to assess effects on T helper cells and cytokine levels and applied to cultured lung epithelial cells to evaluate apoptosis and cytokine secretion. RESULTS: rDer p 22 bound to IgE in 93.75% of sera from pediatric allergic asthma patients. Mice challenged with rDer p 22 had altered Th1/Th2 ratios in spleen and lymph, and lower levels of cytokines IFN-γ but higher levels of IL-4 and IL-10 in alveolar lavage fluid compared with controls (p < .05). Cultured lung epithelial cells had greater apoptosis rates and exhibited higher levels of IL-6, IL-8, and GM-CSF when treated with rDer p 22 compared with control treatment (p < .05). CONCLUSIONS: Recombinant Der p 22 exhibited high IgE-binding rates in allergic children, indicating the activity of the recombinant protein and suggesting this novel allergen may be appropriate for inclusion in an allergy diagnostic workup. This finding is supported by in vitro and mouse in vivo studies showing rDer p 22 induced strong allergenic reactivity and apoptosis.
Asunto(s)
Antígenos Dermatofagoides , Proteínas de Artrópodos , Asma , Hipersensibilidad , Alérgenos , Animales , Antígenos Dermatofagoides/genética , Antígenos Dermatofagoides/inmunología , Proteínas de Artrópodos/genética , Proteínas de Artrópodos/inmunología , Asma/metabolismo , Asma/microbiología , Clonación Molecular , Citocinas/metabolismo , Dermatophagoides pteronyssinus , Polvo , Humanos , Inmunoglobulina E/química , Inmunoglobulina E/metabolismo , Ratones , PyroglyphidaeRESUMEN
BACKGROUND: High hydrostatic pressure (HHP) treatment has been used to alleviate the allergenicity of soybeans, but there are little data about the potential antigenicity of ß-conglycinin after HHP treatment. RESULTS: We examined the effects of HHP treatment on the antigenicity and structure of ß-conglycinin. When the pressure was 300 and 400 MPa, HHP treatment reduced the immunoglobulin (Ig)G binding capacity of ß-conglycinin, while its IgE binding capacity did not change significantly. After in vitro digestion, both the IgE and IgG binding of ß-conglycinin was obviously inhibited after HHP treatment at 400 MPa and 60 °C, although its binding capacity with linear epitope antibodies increased. Moreover, HHP treatment changed the secondary structure of ß-conglycinin, the content of α-helix and random coils increased, while the ß-sheet and ß-turn decreased. After HHP treatment, the conformational structure was unfolded so that a large number of hydrophobic regions were exposed. CONCLUSION: HHP treatment alleviated the potential antigenicity of ß-conglycinin by modifying its structure, which facilitated in vitro digestion and destroyed epitopes. This research provides a new insight into the mechanism of HHP treatment that affects the sensitization of soy protein allergens. © 2022 Society of Chemical Industry.
Asunto(s)
Alérgenos , Proteínas de Soja , Antígenos de Plantas , Digestión , Epítopos , Globulinas , Presión Hidrostática , Inmunoglobulina E/química , Proteínas de Almacenamiento de Semillas , Proteínas de Soja/químicaRESUMEN
BACKGROUND AND OBJECTIVES: Although exposure to stings has been identified as the leading risk factor for anaphylaxis due to Hymenoptera venom allergy, professional beekeepers receive hundreds of stings yearly without developing systemic reactions. This study aims to analyze the mechanisms underlying bee venom tolerance in beekeepers. METHODS: A cross-sectional study was conducted. Participants were recruited and classified into 3 groups: allergic patients (APs), who experienced systemic reactions after bee stings, with a positive intradermal test and specific IgE (sIgE) to Apis mellifera venom (AmV); tolerant beekeepers (TBKs), who received ≥50 stings/year; and healthy nonexposed controls (HCs). We measured serum levels of sIgE and specific IgG4 (sIgG4) to AmV, rApi m 1, rApi m 2, rApi m 3, Api m 4, rApi m 5, and rApi m10, as well as AmV-induced basophil degranulation, percentage of T-cell subsets, regulatory T cells (Treg), and IL-10 production. RESULTS: Compared with TBKs, APs had high levels of sIgE to AmV and all its allergic components (P<.001), together with a high basophil activation rate (P<.001). Conversely, compared with APs, TBKs had higher levels of sIgG4 (P<.001) and IL-10 (P<.0001), as well as an enhanced CTLA-4+ Treg population (P=.001), expanded Helios- Treg (P<.003), and reduced type 1 helper T cells (TH1) (P=.008), TH2 (P=.004), and TH17 (P=.007) subsets. CONCLUSIONS: The profile of TBKs, which was strongly marked by Treg activity, differed from that of TBKs. This natural tolerance would be led by the expansion of inducible Helios- Treg cells at the peripheral level. The Helios- Treg population could be a novel candidate biomarker for monitoring tolerance.
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Anafilaxia , Venenos de Abeja , Hipersensibilidad , Tolerancia Inmunológica , Mordeduras y Picaduras de Insectos , Linfocitos T Reguladores , Humanos , Anafilaxia/diagnóstico , Anafilaxia/metabolismo , Abejas , Estudios Transversales , Hipersensibilidad/diagnóstico , Inmunoglobulina E/química , Inmunoglobulina G/química , Mordeduras y Picaduras de Insectos/complicaciones , Mordeduras y Picaduras de Insectos/inmunología , Interleucina-10RESUMEN
BACKGROUND: Immune epitopes of allergens are pivotal for development of novel diagnostic and therapeutic modalities. Present study aims to identify antigenic determinants of Per a 5, a clinically relevant cross reactive cockroach allergen. METHODS: The three dimensional structure of Per a 5 was modelled using Modeller 9v11 software. A combination of sequence and structure based computational tools were employed for predicting B cell epitopes. Epitopes were synthesized and immunoreactivity was assessed by ELISA using cockroach hypersensitive patient's sera. Cross-reactivity potential of predicted epitopes was assessed with SDAP and ConSurf and validated by IgE ELISA with fungal and mite hypersensitive patient's sera. RESULTS: Per a 5 structure exhibited good quality factor in ERRAT and high stereochemical stability. In silico analysis revealed six B cell epitopes (BC-P1 to P6). BC-P3 demonstrated significant IgE binding followed by BC-P2 and BC-P1 with cockroach hypersensitive patient's sera. Per a 5 epitopes demonstrate considerable similarity with broad spectrum of allergens from fungal, mites, helminths, fruits and nuts. Analysis of PD values indicate BC-P4 to be well conserved among dust mite and helminth GSTs (8.89, 10.63 and 10.69 with D. pteronyssinus, W. bancrofti and F. hepatica respectively). ConSurf analysis of Per a 5 revealed specific enrichment of evolutionarily similar amino acid residues in BC-P2 (with fungal and mite GSTs) and BC-P4 (with mite and helminth GSTs). Further, IgE binding analysis of epitopes demonstrate BC-P2, BC-P3 and BC-P5 as high IgE binders in fungal hypersensitive sera while BC-P1, BC-P2, BC-P4 and BC-P5 demonstrated significant IgE binding with mite hypersensitive sera. CONCLUSIONS: Among the predicted epitopes, BC-P3 demonstrates maximal IgE binding ability. Computational analysis suggests strong evolutionary conservation and cross reactive potential of BC-P4 with allergens in dust mite and helminths. ELISA highlights predictive potential of analysing evolutionarily conserved residues for uncovering potentially cross reactive antigenic determinants. GENERAL SIGNIFICANCE: Immune epitopes of Per a 5 were identified for aiding molecular diagnosis and potential cross reactivity.
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Alérgenos/inmunología , Biología Computacional , Mapeo Epitopo/métodos , Epítopos de Linfocito B/inmunología , Glutatión Transferasa/inmunología , Proteínas de Insectos/inmunología , Algoritmos , Alérgenos/química , Sustitución de Aminoácidos , Animales , Sitios de Unión , Biología Computacional/métodos , Secuencia Conservada , Reacciones Cruzadas/inmunología , Epítopos de Linfocito B/química , Evolución Molecular , Glutatión Transferasa/química , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Inmunoglobulina E/química , Inmunoglobulina E/inmunología , Proteínas de Insectos/química , Modelos Moleculares , Péptidos/química , Péptidos/inmunología , Unión Proteica , Conformación Proteica , Relación Estructura-ActividadRESUMEN
Crustacean allergy, especially to shrimp, is the most predominant cause of seafood allergy. However, due to the high flexibility of immunoglobulin E (IgE), its three-dimensional structure remains unsolved, and the molecular mechanism of shrimp allergen recognition is unknown. Here a chimeric IgE was built in silico, and its variable region in the light chain was replaced with sequences derived from shrimp tropomyosin (TM)-allergic patients. A variety of allergenic peptides from the Chinese shrimp TM were built, treated with heating, and subjected to IgE binding in silico. Amino acid analysis shows that the amino acid residue conservation in shrimp TM contributes to eliciting an IgE-mediated immune response. In the shrimp-allergic IgE, Glu98 in the light chain and other critical residues that recognize allergens from shrimp are implicated in the molecular basis of IgE-mediated shrimp allergy. Heat treatment could alter the conformations of TM allergenic peptides, impact their intramolecular hydrogen bonding, and subsequently decrease the binding between these peptides and IgE. We found Glu98 as the characteristic amino acid residue in the light chain of IgE to recognize general shrimp-allergic sequences, and heat-induced conformational change generally desensitizes shrimp allergens.
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Alérgenos/inmunología , Hipersensibilidad a los Alimentos/inmunología , Inmunoglobulina E/inmunología , Penaeidae/inmunología , Mariscos , Tropomiosina/química , Tropomiosina/inmunología , Alérgenos/química , Secuencia de Aminoácidos , Animales , Epítopos/inmunología , Hipersensibilidad a los Alimentos/terapia , Calor , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Inmunoglobulina E/química , Inmunoglobulina E/metabolismo , Terapia de Inmunosupresión , Modelos Moleculares , Simulación de Dinámica Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/inmunología , Fragmentos de Péptidos/metabolismo , Conformación Proteica , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/inmunología , Alineación de Secuencia , Tropomiosina/metabolismoRESUMEN
Currently, there is a need to explore the effects of different types of protein-anthocyanin complexations, as well as the possible changes in the nutrition and allergenicity of the formed complexes. Here, we systematically investigated the covalent and non-covalent interactions between cyanidin-3-O-glucoside (C3G) and two major milk proteins, α-casein (α-CN) and ß-lactoglobulin (ß-LG). Fluorescence quenching data showed that, under non-covalent conditions, C3G quenched the fluorescence of the two proteins via a static process, with the interaction forces being revealed; for covalent products, decreased fluorescence intensities were observed with red shifts in the λmax. Multiple spectroscopic analyses implied that C3G-addition induced protein structural unfolding through transitions between the random coil and ordered secondary components. With a two-stage simulated gastrointestinal (GI) digestion model, it was seen that covalent complexes, not their non-covalent counterparts, showed reduced protein digestibility, ascribed to structural changes resulting in the unavailability of enzyme cleaving sites. The GI digests displayed prominent 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation-scavenging abilities (3.8-11.1 mM Trolox equivalents per mL digest), in contrast to the markedly reduced 1,1-diphenyl-2-picrylhydrazyl radical-scavenging capacities. Additionally, covalent protein-C3G complexes, but not their non-covalent counterparts, showed lower IgE-binding levels in comparison to the native control. This study provides new understanding for the development of anthocyanin-milk protein systems as functional ingredients with health-beneficial properties.
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Alérgenos/inmunología , Antocianinas/química , Caseínas/química , Lactoglobulinas/química , Animales , Antocianinas/inmunología , Antocianinas/metabolismo , Caseínas/inmunología , Caseínas/metabolismo , Digestión , Dispersión Dinámica de Luz/métodos , Humanos , Inmunoglobulina E/química , Inmunoglobulina E/inmunología , Lactoglobulinas/inmunología , Lactoglobulinas/metabolismo , Proteínas de la Leche/química , Proteínas de la Leche/inmunología , Proteínas de la Leche/metabolismo , Tamaño de la Partícula , Unión Proteica , Conformación Proteica , Espectrometría de Fluorescencia/métodosRESUMEN
Periostin is known to be a useful biomarker for various diseases. In this article, we focus on allergic diseases and pulmonary fibrosis, for which we and others are now developing detection systems for periostin as a biomarker. Biomarker-based precision medicine in the management of type 2 inflammation and fibrotic diseases since heterogeneity is of utmost importance. Periostin expression is induced by type 2 cytokines (interleukin-4/-13) or transforming growth factor-ß, and plays a vital role in the pathogenesis of allergic inflammation or interstitial lung disease, respectively, andits serum levels are correlated disease severity, prognosis and responsiveness to the treatment. We first summarise the importance of type 2 biomarker and then describe the pathological role of periostin in the development and progression of type 2 allergic inflammation and pulmonary fibrosis. In addition, then, we summarise the recent development of assay methods for periostin detection, and analyse the diseases in which periostin concentration is elevated in serum and local biological fluids and its usefulness as a biomarker. Furthermore, we describe recent findings of periostin as a biomarker in the use of biologics or anti-fibrotic therapy. Finally, we describe the factors that influence the change in periostin concentration under the healthy conditions.
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Biomarcadores/metabolismo , Moléculas de Adhesión Celular/química , Inflamación/metabolismo , Fibrosis Pulmonar/metabolismo , Enfermedad Crónica , Citocinas/metabolismo , Eosinofilia/metabolismo , Fibrosis/patología , Humanos , Fibrosis Pulmonar Idiopática/metabolismo , Fibrosis Pulmonar Idiopática/patología , Inmunoglobulina E/química , Inflamación/patología , Interleucina-13/metabolismo , Pulmón/metabolismo , Medicina de Precisión , Pronóstico , Fibrosis Pulmonar/patología , Rinitis/metabolismo , Sinusitis/metabolismo , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
The recent emergence of anti-immunoglobulin E (IgE) drugs and their candidates for humans has endorsed the significance of IgE-dependent pathways in allergic disorders. IgE is distributed locally in the tissues or systemically to confer a sensory mechanism in a domain of adaptive immunity to the otherwise innate type of effector cells, namely, mast cells and basophils. Bound on the high-affinity IgE receptor FcεRI, IgE enables fast memory responses against revisiting threats of venoms, parasites, and bacteria. However, the dysregulation of IgE-dependent reactions leads to potentially life-threatening allergic diseases, such as asthma and anaphylaxis. Therefore, reactivity of the IgE sensor is fine-tuned by various IgE-associating molecules. In this review, we discuss the mechanistic basis for how IgE-dependent mast cell activation is regulated by the IgE-associating molecules, including the newly developed therapeutic candidates.
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Inmunoglobulina E/metabolismo , Mastocitos/inmunología , Animales , Galectinas/metabolismo , Glicosilación , Histamina/metabolismo , Humanos , Inmunoglobulina E/química , Receptores de IgE/metabolismoRESUMEN
Mesoporous silica (MS) particles have been explored for various healthcare applications, but universal data about their safety and/or toxicity are yet to be well-established for clinical purposes. Information about general toxicity of hollow MS (HMS) particles and about immunotoxicity of MS particles are significantly lacked. Therefore, acute toxicity and immunotoxicity of HMS particles were experimentally evaluated. A systematic and objective literature study was parallelly performed to analyze the published in vivo toxicity of MS particles. Lethal acute toxicity of MS particles is likely to arise from their physical action after intravenous and intraperitoneal administrations, and only rarely observed after subcutaneous administration. No clear relationship was identified between physicochemical properties of MS particles and lethality as well as maximum tolerated dose with some exceptions. At sub-lethal doses, MS particles tend to accumulate mainly in lung, liver, and spleen. The HMS particles showed lower inflammation-inducing ability than polyinosinic-polycytidylic acid and almost the same allergy-inducing ability as Alum. Finally, the universal lowest observed adverse effect levels were determined as 0.45, 0.81, and 4.1 mg/kg (human equivalent dose) for intravenous, intraperitoneal, and subcutaneous administration of MS particles, respectively. These results could be helpful for determining an appropriate MS particle dose in clinical study.
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Nanopartículas del Metal/administración & dosificación , Nanopartículas del Metal/química , Dióxido de Silicio/química , Animales , Contención de Riesgos Biológicos , Diseño de Fármacos , Hidrólisis , Inmunoglobulina E/química , Inflamación , Infusiones Intravenosas , Inyecciones Intraperitoneales , Inyecciones Subcutáneas , Masculino , Dosis Máxima Tolerada , Ratones , Nanopartículas/química , Tamaño de la Partícula , Porosidad , Silanos/química , Pruebas de ToxicidadRESUMEN
Ovalbumin (OVA), one of the major allergens in hen egg, exhibits extensive structural heterogeneity due to a range of post-translational modifications (PTMs). However, analyzing the structural heterogeneity of native OVA is challenging, and the relationship between heterogeneity and IgG/IgE-binding of OVA remains unclear. In this work, ion exchange chromatography (IXC) with salt gradient elution and on-line detection by native electrospray ionization mass spectrometry (ESI MS) was used to assess the structural heterogeneity of OVA, while inhibition-ELISA was used to assess the IgG/IgE binding characteristics of OVA. Over 130 different OVA proteoforms (including glycan-free species and 32 pairs of isobaric species) were identified. Proteoforms with acetylation, phosphorylation, oxidation and succinimide modifications had reduced IgG/IgE binding capacities, whereas those with few structural modifications had higher IgG/IgE binding capacities. OVA isoforms with a sialic acid-containing glycan modification had the highest IgG/IgE binding capacity. Our results demonstrate that on-line native IXC/MS with salt gradient elution can be used for rapid assessment of the structural heterogeneity of proteins. An improved understanding of the relationship between IgG/IgE binding capacity and OVA structure provides a basis for developing biotechnology or food processing methods for reducing protein allergenicity reduction.
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Inmunoglobulina E/química , Inmunoglobulina G/química , Ovalbúmina/química , Alérgenos/química , Alérgenos/inmunología , Animales , Pollos , Hipersensibilidad al Huevo/inmunología , Humanos , Inmunoglobulina E/inmunología , Inmunoglobulina G/inmunología , Ovalbúmina/inmunología , Unión Proteica , Conformación ProteicaRESUMEN
The binding of nickel by immune proteins can manifest as Type IV contact dermatitis (Ni-specific T cells mediated) and less frequently as Type I hypersensitivity with both mechanisms remaining unknown to date. Since there are reports of patients co-manifesting the two hypersensitivities, a common mechanism may underlie both the TCR and IgE nickel binding. Focusing on Trastuzumab and Pertuzumab IgE variants as serendipitous investigation models, we found Ni-NTA interactions independent of Her2 binding to be due to glutamine stretches. These stretches are both Ni-inducible and in fixed pockets at the antibody complementarity-determining regions (CDRs) and framework regions (FWRs) of both the antibody heavy and light chains with influence from the heavy chain constant region. Comparisons with TCRs structures revealed similar interactions, demonstrating the possible underlying mechanism in selecting for Ni-binding IgEs and TCRs respectively. With the elucidation of the interaction, future therapeutic antibodies could also be sagaciously engineered to utilize such nickel binding for biotechnological purposes.