Search

Eosinophils are a common clinical feature associated with chronic allergic diseases, and elemental diets, systemic steroids, anti‐IL‐5 and anti‐IL‐13 treatment have shown some therapeutic promise. Herein, we present evidence that pre‐ and post‐intraperitoneal administration of tacrolimus (FK506) is very effective in reducing CCR3/Siglec‐F(+) eosinophils in Aspergillus‐challenged asthma and EoE, CD2‐IL‐5 induced global eosinophilia, and DOX regulated IL‐13‐induced asthma. We used flow cytometry and anti‐major basic protein (MBP) immunostaining to examine eosinophils in the spleen, bone marrow, BALF, lung, oesophagus and intestine. Additionally, we also performed ELISA and Western blot analyses to show that tacrolimus treatment also reduces the levels of eosinophil‐specific cytokines IL‐4, IL‐5, IL‐13 and TGF‐β, eosinophil‐specific chemokines Eotaxin‐1 and Eotaxin‐2, and progenitors of target RCAN1 mRNA and protein levels. Additionally, the current investigations also show that the TGF‐β‐mediated oesophageal and lung fibrosis is also reduced in Aspergillus‐challenged, CD2‐IL‐5 transgenic and DOX‐responsive IL‐13 mice. Mechanistically, we show that tacrolimus in vitro treatment inhibited bone marrow‐derived eosinophil proliferation and viability by promoting eosinophil apoptosis that may be associated with downregulation of RCAN1. Taken together, we provide in vivo and in vitro evidence that tacrolimus ameliorates eosinophil levels and associated pathogenesis in allergen‐, IL‐5‐ and IL‐13‐induced EoE, EG and asthma pathogenesis. Considering tacrolimus side‐effects and reactivity to several other drugs, we propose the topical use of tacrolimus for paediatric and low‐dose oral for adult patients as a novel therapeutic strategy for the clinical trial to reduce mucosal eosinophilia first in steroid‐refractory or elemental diet non‐responsive adult EoE, EG and asthma patients.

Baseline eosinophils reside in the gastrointestinal tract; however, in several allergic disorders, excessive eosinophils accumulate in the blood as well in the tissues. Recently, we showed in vitro that interleukin (IL)‐18 matures and transforms IL‐5‐generated eosinophils into the pathogenic eosinophils that are detected in human allergic diseases. To examine the role of local induction of IL‐18 in promoting eosinophil‐associated intestinal disorders, we generated enterocyte IL‐18‐overexpressing mice using the rat intestinal fatty acid‐binding promoter (Fabpi) and analysed tissue IL‐18 overexpression and eosinophilia by performing real‐time polymerase chain reaction, Enzyme‐Linked Immunosorbent Assay and anti‐major basic protein immunostaining. Herein we show that Fabpi‐IL‐18 mice display highly induced IL‐18 mRNA and protein in the jejunum. IL‐18 overexpression in enterocytes promotes marked increases of eosinophils in the blood and jejunum. Our analysis shows IL‐18 overexpression in the jejunum induces a specific population of CD101(+ ) CD274(+) tissue eosinophils. Additionally, we observed comparable tissue eosinophilia in IL‐13‐deficient‐Fabpi‐IL‐18 mice, and reduced numbers of tissue eosinophils in eotaxin‐deficient‐Fabpi‐IL‐18 and IL‐5‐deficient‐Fabpi‐IL‐18 mice compared with Fabpi‐IL‐18 transgenic mice. Notably, jejunum eosinophilia in IL‐5‐deficient‐Fabpi‐IL‐18 mice is significantly induced compared with wild‐type mice, which indicates the direct role of induced IL‐18 in the tissue accumulation of eosinophils and mast cells. Furthermore, we also found that overexpression of IL‐18 in the intestine promotes eosinophil‐associated peanut‐induced allergic responses in mice. Taken together, we provide direct in vivo evidence that induced expression of IL‐18 in the enterocytes promotes eotaxin‐1, IL‐5 and IL‐13 independent intestinal eosinophilia, which signifies the clinical relevance of induced IL‐18 in eosinophil‐associated gastrointestinal disorders (EGIDs) to food allergens.

The current studies demonstrate a critical role of IL-18 in transforming IL-5 generated naïve eosinophils into the distinct inflammatory CD101(+)CD274(+) expressing mature and activated tissue eosinophils that promote disease pathogenesis.

Eosinophilic pancreatitis (EP) is reported in humans; however, the etiology and role of eosinophils in EP pathogenesis are poorly understood and not well explored. Therefore, it is interesting to examine the role of eosinophils in the initiation and progression of pancreatitis pathogenesis. Accordingly, we performed anti-major basic protein immunostaining, chloroacetate esterase, and Masson’s trichrome analyses to detect eosinophils, mast cells, and collagen in the tissue sections of mouse and human pancreas. Induced eosinophils accumulation and degranulation were observed in the tissue sections of human pancreatitis, compared with no eosinophils in the normal pancreatic tissue sections. Similarly, we observed induced tissue eosinophilia along with mast cells and acinar cells atrophy in cerulein-induced mouse model of chronic pancreatitis. Additionally, qPCR and ELISA analyses detected induced transcript and protein levels of proinflammatory and profibrotic cytokines, chemokines like IL 5, IL-18, eotaxin-1, eotaxin-2, TGF-β1, collagen-1, collagen-3, fibronectin, and α-SMA in experimental pancreatitis. Mechanistically, we show that eosinophil-deficient GATA1 and endogenous IL-5-deficient mice were protected from the induction of proinflammatory and profibrotic cytokines, chemokines, tissue eosinophilia, and mast cells in a cerulein-induced murine model of pancreatitis. These human and experimental data indicate that eosinophil accumulation and degranulation may have a critical role in promoting pancreatitis pathogenesis including fibrosis. Taken together, eosinophil tissue accumulation needs appropriate attention to understand and restrict the progression of pancreatitis pathogenesis in humans.NEW & NOTEWORTHY The present study for the first time shows that eosinophils accumulate in the pancreas and promote disease pathogenesis, including fibrosis in earlier reported cerulein-induced experimental models of pancreatitis. Importantly, we show that GATA-1 and IL-5 deficiency protects mice form the induction of eosinophil active chemokines, and profibrotic cytokines, including accumulation of tissue collagen in an experimental model of pancreatitis. Additionally, we state that cerulein-induced chronic pancreatitis is independent of blood eosinophilia.

Interleukin (IL)-15 overexpression in eosinophilic gastrointestinal disorders is reported, but IL-15’s role in promoting eosinophilia gastroenteritis is largely unknown. Therefore, we generated enterocyte-overexpressed IL-15 transgenic mice using Fabpi-promoter. The Fabpi-IL-15 (iIL-15) transgenic mice show induced IL-15 levels in the jejunum with a marked increase in jejunum eosinophils. However, no induction of eosinophilia in the blood or any other gastrointestinal segment was observed. Eosinophilia in the jejunum villus was substantially higher in iIL-15 mice compared to wild type mice. In addition, goblet cell hyperplasia was also observed in the jejunum of iIL-15 mice. Furthermore, a significant correlation between induced IL-15 transcript and the IL-18 transcripts was observed. Therefore, to further understand the role of IL-18 in IL-15 mice associated gastrointestinal disorders; we generated iIL-15/IL-18Rα(−/−) mice. Using these mice, we found that IL-18 has an important role in promoting IL-15-induced eosinophilia. Since intestinal IL-15 overexpression is reported in food intolerance; we examined OVA intolerance in iIL-15 mice. The OVA-sensitized and challenged iIL-15 mice experienced weight loss, diarrhea, and eosinophilia in the jejunum. Taken together, our findings demonstrate that intestinal IL-15 overexpression induces IL-18-dependent eosinophilia and immunoglobulin in the intestine that promotes food allergic responses.

Worldwide increase incidences of allergic diseases have heightened the interest of clinicians and researchers to understand the role of neuroendocrine cells in the recruitment and activation of inflammatory cells. Several pieces of evidence revealed the association of neuropeptides in the pathogenesis of allergic diseases. Importantly, one such peptide that is secreted by neuronal cells and immune cells exerts a wide spectrum of immunological functions as cytokine/chemokine is termed as Vasoactive Intestinal Peptide (VIP). VIP mediates immunological function through interaction with specific receptors namely VPAC-1, VPAC-2, CRTH2 and PAC1 that are expressed on several immune cells such as eosinophils, mast cells, neutrophils, and lymphocytes; therefore, provide the basis for the action of VIP on the immune system. Additionally, VIP mediated action varies according to target organ depending upon the presence of specific VIP associated receptor, involved immune cells and the microenvironment of the organ. Herein, we present an integrative review of the current understanding on the role of VIP and associated receptors in allergic diseases, the presence of VIP receptors on various immune cells with particular emphasis on the role of VIP in the pathogenesis of allergic diseases such as asthma, allergic rhinitis, and atopic dermatitis. Being crucial signal molecule of the neuroendocrine-immune network, the development of stable VIP analogue and/or antagonist may provide the future therapeutic drug alternative for the better treatment of these allergic diseases. Taken together, our current review summarizes the current understandings of VIP biology and further explore the significance of neuroendocrine cells derived VIP in the recruitment of inflammatory cells in allergic diseases that may be helpful to the investigators for planning the experiments and accordingly predicting new therapeutic strategies for combating allergic diseases. Summarized graphical abstract will help the readers to understand the significance of VIP in allergic diseases.

Food allergy, a commonly increasing problem worldwide, defined as an adverse immune response to food. A variety of immune-related effector cells such as mast cells, eosinophils, neutrophils, and T cells are involved in food-related allergic responses categorized as IgE-mediated, non-IgE mediated, and mixed (IgE and non-IgE) depending upon underlying immunological mechanisms. The dietary antigens mainly target the gastrointestinal tract including pancreas that gets inflamed due to food allergy and leads acute pancreatitis. Reports indicate several food proteins induce pancreatitis; however, detailed underlying mechanism of food-induced pancreatitis is unexplored. The aim of the review is to understand and update the current scenario of food-induced pancreatitis. A comprehensive literature search of relevant research articles has been performed through PubMed and articles were chosen based on their relevance to food allergen mediated pancreatitis. Several cases in the literature indicating that acute pancreatitis has been provoked after the consumption of mustard, milk, egg, banana, fish, and kiwi fruits. Food-induced pancreatitis is an ignored and unexplored area of research. The review highlights the significance of food in the development of pancreatitis and draws the attention of physicians and scientists to consider food allergies as a possible cause for initiation of pancreatitis pathogenesis.

Epicutaneous (EC) sensitization to food allergens may occur when the skin has been lightly damaged. The study here tested whether cutaneous exposure to pigeon pea protein(s) may cause allergic sensitization. BALB/c mice were either orally gavaged or epicutaneously sensitized by repeated application of pigeon pea crude protein extract (CPE) on undamaged areas of skin without any adjuvant; afterwards, both groups were orally challenged with the pigeon pea CPE. Anaphylactic symptoms along with measures of body temperature, MCPT-1, TSLP, pigeon pea-specific IgE and IgG1, myeloperoxidase (MPO) activity, TH2 cytokines, TH2 transcription factors (TFs) and filaggrin expression were determined. Mast cell staining, eosinophil levels and histopathological analysis of the skin and intestines were also performed. In the epicutaneously-sensitized mice, elevated levels of specific IgE and IgG1, as well as of MCPT-1, TSLP, TH2 cytokines and TFs, higher anaphylactic scores and histological changes in the skin and intestine were indicative of sensitization ability via both routes in the pigeon pea CPE-treated hosts. Elevated levels of mast cells were observed in both the skin and intestine; increased levels of eosinophils and MPO activity were noted only in the skin. Decreased levels of filaggrin in skin may have played a key role in the skin barrier dysfunction, increasing the chances of sensitization. Therefore, the experimental data support the hypothesis that in addition to oral exposure, skin exposure to food allergens can promote TH2-dependent sensitization, IgE-mediated anaphylaxis and intestinal changes after oral challenge. Based on this, an avoidance of cutaneous exposures to allergens might prevent development of food anaphylaxis.

Chickpea (CP), a legume of the family Fabaceae, is an important nutrient-rich food providing protein, essential amino acids, vitamins, dietary fibre, and minerals. Unfortunately, several IgE-binding proteins in CP have been detected that are responsible for allergic manifestations in sensitized population. Therefore, the prevalence of CP induced allergy prompted us towards purification, characterization and allergenicity assessment of a major ∼26kDa protein from chickpea crude protein extract (CP-CPE). Purification of CP 26kDa protein was done using a combination of fractionation and anion exchange chromatography. This protein was further characterized as "Chain A, crystal structure of a plant albumin" from Cicer arietinum with Mol wt 25.8kDa by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Further, allergenic potential of purified 25.8kDa protein was assessed using in vivo and in vitro model. Purified protein showed IgE-binding capacity with sensitized BALB/c mice and CP allergic patient's sera. Enhanced levels of specific and total IgE, MCP-1, MCPT-1, myeloperoxidase, histamine, prostaglandin D2, and cysteinyl leukotriene were found in sera of mice treated with CP ∼26kDa protein. Further, expressions of Th2 cytokines (i.e. IL-4, IL-5, IL-13), transcription factors (i.e. GATA-3, STAT-6, SOCS-3) and mast cell signaling proteins (Lyn, cFgr, Syk, PLC-γ2, PI-3K, PKC) were also found increased at mRNA and protein levels in the intestines of mice treated with CP ∼26kDa protein. In addition, enhanced release of β-hexosaminidase, histamine, cysteinyl leukotriene and prostaglandin D2 were observed in RBL2H3 cell line when treated (125μg) with CP 26kDa protein. Conclusively, in vivo and in vitro studies revealed the allergenic potential of purified CP 26kDa protein. Being a potential allergen, plant albumin may play a pivotal role in CP induced allergenicity. Current study will be helpful for better development of therapeutic approaches to prevent the allergenicity in CP sensitized individuals.

The tranquillizing effects of quercetin on allergic asthma are promising, but its poor water solubility and bioavailability is still a bottleneck. In this study, an ovalbumin (OVA) sensitized BALB/c mice asthma model was used to investigate the potential of quercetin nanocrystals (nQ) on relieving asthma aggravation. The water soluble nQ was prepared by the homogenization using the high energy sonication method. X-ray diffraction data showed the formation of nQ (10-30 nm) which was in agreement with transmission electron microscopy. The nQ was found to be more stable and soluble in PBS, and sera of BALB/c mice compared to bulk quercetin. Dose dependent experiments with nQ on OVA sensitized asthma mice exhibited significant anti-asthmatic potential of nQ at much lower dose (1 mg/kg body weight) compared to bulk quercetin. The treatment of nQ remarkably resulted in reduced OVA specific immunoglobulin E (sIgE) production, anaphylaxis signs and type 1 skin test. The nQ also significantly modulated the expression of Th2 cytokines like IL-4 and IL-5, which are responsible for IgE class switching and suppressed the degranulation/secretion of different chemical mediators (PGD2, mMCPT-1 Cys-L and TSLP) from activated mast cells. The levels of FcεR1, Syk, c-Yes, PI-3, p-PI-3, PLC-γ2, and p-PLC-γ2 were found to be reduced in the OVA sensitized BALB/c mice treated with nQ compared to those treated with OVA only. The results indicate that nQ alleviate pulmonary inflammation and airway hyporesponsiveness in allergic asthma at much lower dose compared to bulk quercetin and may be considered as a potential drug for the treatment of asthmatic patients.

Mustard is widely used in a variety of foods/food products to enhance the flavor and nutritional value that subsequently raise the risk of hypersensitivity reactions. Mustard allergy has been reported for many years and is increasing gradually especially in the areas where its consumption is comparatively higher, and it may be considered among the most important food allergies. A number of relevant clinical studies focused on mustard-induced allergic manifestations are summarized in the current review. In addition, the knowledge regarding the immunological as well as biochemical characteristics of mustard allergens that have been known till date and their cross-reactivity with other food allergens have also been discussed here. Notably, mustard may also be present as a hidden allergen in foods; therefore, it is important to recognize food products that may contain mustard as it may pose potential risk for the allergic individuals. Additionally, the better understanding of the underlying mechanism in mustard allergy is a prerequisite for the development of specific therapeutic procedures. Conclusively, mustard sensitivity should be routinely tested in patients with idiopathic anaphylaxis for the safety of the allergic patients.

The prevalence of black gram (Vigna mungo) induced allergic reactions are reported from several parts of the world including Asia and Australia. But, a thorough exploration of the allergic reactions induced by black gram proteins is still lacking. Therefore, efforts have been made to explore black gram allergy using in vivo and in vitro approaches. In this study, Simulated Gastric Fluid (SGF) assay and IgE immunoblotting were carried out to identify clinically relevant allergens of black gram. BALB/c mice and RBL-2H3 cells were used for elucidation of allergenic reactions of black gram proteins. Further, this study was extended to screen black gram sensitive patients among nasobronchial allergic patients on the basis of clinical history, skin prick test (SPT), specific IgE levels and IgE immunoblotting. Enhanced levels of specific IgE, IgG1/IgG2a (p < 0.05), histamine (p < 0.05), clinical symptoms, pathological indications in the lungs, intestine and spleen were evident in black gram sensitized BALB/c mice. Moreover, the expression of Th2 cytokine transcripts and GATA-3/T-bet ratio was found enhanced in the treated group. In vitro studies on RBL-2H3 cells,showed increased release of β-hexosaminidase (p < 0.05), histamine (p < 0.05), cysteinyl leukotriene (p

Mustard, a widely consumed spice can provoke allergic manifestations in mustard sensitive individuals. The aim of this study is to explore the allergenicity potential of GM mustard varieties (GM-V2 and GM-V4) having increased carotenoid content and compare it with the native (Varuna) and commercially available variety (Urvashi). Mustard protein sensitized (GM and non-GM) BALB/c mice sera were used to identify the allergenic proteins by IgE immunoblotting. Immunoglobulin levels, mouse mast cell protease-1, monocyte chemotactic protein and histamine were measured in serum. The levels of Th1/Th2 transcription factors GATA-3, T-bet, SOCS3, STAT 6 and c-maf in intestinal proteins of all groups were detected by immunoblotting and PCR. Major IgE-binding proteins of 21, 29 and 33kDa were found in all mustard varieties. The enhanced levels of Th2 cytokines IL-4, IL-5 and IL-13 and transcription factors GATA-3 and SOCS-3 were observed. The increased levels of MCP-1, MCPT-1 and histamine were also evident in commercial, native, GM-V2 and GM-V4 varieties of mustard treated groups. Conclusively, all these finding indicate that introduction of GM mustard varieties with increased carotenoid content did not cause any increase in allergenicity as compared to its native counterpart and therefore can be safe from allergenicity point of view.

Objective Broad bean ( Vicia faba L.), a common vegetable, belongs to the family Fabaceae and is consumed worldwide. Limited studies have been done on allergenicity of broad beans. The aim of this study was to determine if broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins. Methods Simulated gastric fluid (SGF) assay and immunoglobulin E (IgE) immunoblotting were carried out to identify pepsin-resistant and IgE-binding proteins. The allergenicity of broad beans was assessed in allergic patients, BALB/c mice, splenocytes, and RBL-2H3 cells. Results Eight broad bean proteins of approximate molecular weight 70, 60, 48, 32, 23, 19, 15, and 10 kDa that remained undigested in SGF, showed IgE-binding capacity as well. Of 127 allergic patients studied, broad bean allergy was evident in 16 (12%). Mice sensitized with broad bean showed increased levels of histamine, total and specific IgE, and severe signs of systemic anaphylaxis compared with controls. Enhanced levels of histamine, prostaglandin D 2 , cysteinyl leukotriene, and β-hexosaminidase release were observed in the primed RBL-2H3 cells following broad bean exposure. The levels of interleukin IL-4, IL-5, IL-13 and regulated on activation, normal T-cell expressed and secreted were found enhanced in broad bean-treated splenocytes culture supernatant compared with controls. Conclusion This study inferred that broad bean proteins have the ability to elicit allergic responses due to the presence of clinically relevant allergenic proteins.

Consumption of green gram (Vigna radiata L. Millsp), a legume (family: fabaceae) induces allergic symptoms in the susceptible individuals. In the present study, an attempt has been made to induce oral tolerance in BALB/c mice as a therapeutic tool for the prevention of green gram allergy. At first set of experiments, BALB/c mice were gavaged with green gram proteins to explore their allergenicity potential. At second set of experiments, BALB/c mice were given a single acute dose ranging from 0.02 mg to 50 mg to induce oral tolerance. At first set of experiments, BALB/c showed enhanced levels of total and specific IgE, Th2 cytokines in the splenocytes and β-hexosaminidase, histamine, prostaglandin D2 and cysteinyl leukotriene release from RBL-2H3 cells when compared to their respective controls. At second set of experiments, the levels of total and specific IgE/IgG1 in the sera, anaphylaxis symptoms, delayed type hypersensitivity (DTH), CD4 + and CD8 + cells were found decreased while increased levels of Foxp3 and IL-10 were observed at the single acute dose of 20 mg green gram when compared to other groups. Taken together the allergenicity of green gram can be minimized due to induction of oral tolerance at a single acute dose of 20 mg in BALB/c mice.

Background: Prevalence of nasobronchial allergy is increasing globally. Several genetic, environmental and other associated factors are responsible for this increase. This study is designed to investigate profile of different allergens sensitivities and associated factors involved in the prevalence of naso-bronchial allergy. Methods: 4312 skin prick tests with 77 allergens in 56 patients of nasobronchial allergy were studied using parameters like age, temporal association between asthma and allergic rhinitis, most common type of allergens, age of onset, sex, residence and family history of atopy. Results: It was found that the age groups 12-40 years are more prone to nasobronchial allergy. 75% patients have shown temporal association between asthma and allergic rhinitis. Most common offending allergens were insects (33.3%), followed by pollens (30.3%), fungi (13.6%), dust (8.3%), non-juicy foods (6.8%), juicy foods (4.16%) and dander (3.03%). Males have shown more prevalence of nasobronchial allergy than that of the females. 32% patients have shown genetic disposition. Conclusions: Overall, this study unravels different associated factors and profile of allergens in patients’ of nasobronchial allergy which will be helpful in diagnosis, management and treatment of asthma.

Pancreatitis is a condition characterized by parenchymal inflammation of the pancreas, which is often associated with lung injury due to low level of oxygen and the condition is termed as acute pancreatitis-associated lung injury (APALI). Clinical reports indicated that ~ 20% to 50% of patients from low oxygen levels in blood with acute respiratory distress syndrome (ARDS). ARDS is a severe form of acute lung injury (ALI), a pulmonary disease with impaired airflow making patients difficult to breathe. ALI is frequently observed in patients with severe acute pancreatitis. Approximately one third of severe pancreatitis patients develop acute lung injury and acute respiratory distress syndrome that account for 60% of all deaths within the first week. The major causes of ALI and ARDS are sepsis, trauma, aspiration, multiple blood transfusion, and most importantly acute pancreatitis. The molecular mechanisms of ALI and ARDS are still not well explored, but available reports indicate the involvement of several pro-inflammatory mediators including cytokines (TNF-α, IL-1β, IL-6) and chemokines [like interleukin-8 (IL-8) and macrophage inhibitory factor (MIF)], as well as macrophage polarization regulating the migration and pulmonary infiltration of neutrophils into the pulmonary interstitial tissue, causing injury to the pulmonary parenchyma. Acute lung injury and acute respiratory distress syndrome in acute pancreatitis remains an unsolved issue and needs more research and resources to develop effective treatments and therapies. However, recent efforts have tested several molecules in an experimental model and showed promising results as a treatment option. The current review summarized the mechanism that is operational in pancreatitis-associated acute respiratory failure and respiratory distress syndrome in patients and current treatment options.

A large number of food allergens, usually proteins capable of inducing allergic symptoms, including severe, even life-threatening reactions in predisposed individuals, have been identified and characterized. As most of these proteins are from our daily dietary intake, they are often difficult to avoid. However, the proteins that cause such immunoglobulin E (IgE)-mediated reactions can be assigned to only a limited number of protein families. Detailed knowledge about the characteristics of food allergens, their structures, biological activity, and stability, may be helpful in improving diagnosis of food allergy, avoiding unnecessary exclusion of diets, and assessing the risk of cross-reactive allergies to other food sources. The purpose of this review is to shed light on the sources and molecular properties of the allergenic proteins, their stability, the mechanisms of the allergenic responses, and recent findings related to prevention of this serious issue.

Allergy to chickpea or Garbanzo bean (Cicer arietinum) has been reported in the Indian population. Little information is found regarding allergenic events involved in the chickpea allergy; therefore, chickpea allergenicity assessment was undertaken. In vivo and ex vivo studies were carried out using BALB/c mice. Chickpea skin prick test positive patients have been used to extend this study in humans. Identification of allergens was carried out by simulated gastric fluids assay for pepsin resistant polypeptides and validated by IgE western blotting using chickpea sensitive humans and sensitized mice sera. Our data have shown the occurrence of a systemic anaphylactic reaction resulting in reduced body temperature after challenge along with significantly increased levels of IgE, IgG1, MMCP-1, CCL-2 as well as histamine. Further, increased Th1/Th2 (mixed) cytokine response was observed in spleen cell culture supernatants. Jejunum, lungs and spleen showed prominent histopathological changes specific for allergic inflammation. Immunoblotting with pooled sera of either sensitized mice or human sera recognized seven similar IgE binding polypeptides that may be responsible for chickpea induced hypersensitivity reactions. This study has addressed the allergenic manifestations associated with chickpea consumption and identifies the proteins responsible for allergenicity which may prove useful in diagnosis and management of allergenicity of legumes especially chickpea.

Allergenicity potential of red kidney beans (Phaseolus vulgaris cv chitra) was assessed and attempts were made to identify the responsible proteins by pepsin digestibility assay and IgE immunoblotting. To evaluate allergenic potential, BALB/c mice were sensitized with red kidney bean proteins and levels of specific immunoglobulin, histamine, mast cell protease-1, cytokines and CCL-2 were measured. To confirm our findings in BALB/c, the studies were also extended to human subjects. Human sera collected from control subjects and allergic patients after skin prick test were used for IgE immunoblotting, measuring the levels of total and specific IgE and determining cross reactivity of red kidney bean with other legumes. Red kidney bean allergenic potential was evident by significant increase in specific IgE, IgG1, histamine, mast cell protease-1 and Th2 cytokine levels in comparison to control. Enhanced level of eosinophils in jejunum, prominent anaphylactic symptoms, and eruptive histopathological changes give indication towards red kidney beans allergenicity. IgE immunoblotting detected five protein components with molecular weights of approximately 170, 100, 43, 34 and 20 kDa. Red kidney bean proteins showed cross reactivity with peanut, soybean, chickpea and black gram. Finally, this work demonstrated that red kidney beans may induce allergic response in mice similar to human subjects, with identification of five clinically relevant allergenic protein components.

Development of genetically modified (GM) crops is on increase to improve food quality, increase harvest yields, and reduce the dependency on chemical pesticides. Before their release in marketplace, they should be scrutinized for their safety. Several guidelines of different regulatory agencies like ILSI, WHO Codex, OECD, and so on for allergenicity evaluation of transgenics are available and sequence homology analysis is the first test to determine the allergenic potential of inserted proteins. Therefore, to test and validate, 312 allergenic, 100 non-allergenic, and 48 inserted proteins were assessed for sequence similarity using 8-mer, 80-mer, and full FASTA search. On performing sequence homology studies, ~94% the allergenic proteins gave exact matches for 8-mer and 80-mer homology. However, 20 allergenic proteins showed non-allergenic behavior. Out of 100 non-allergenic proteins, seven qualified as allergens. None of the inserted proteins demonstrated allergenic behavior. In order to improve the predictability, proteins showing anomalous behavior were tested by Algpred and ADFS separately. Use of Algpred and ADFS softwares reduced the tendency of false prediction to a great extent (74-78%). In conclusion, routine sequence homology needs to be coupled with some other bioinformatic method like ADFS/Algpred to reduce false allergenicity prediction of novel proteins.

Airway obstruction is a highly specific term that represents physiologic abnormalities of the airways and induced levels is observed in steroid treated asthmatic patients. We tested the hypothesis that regulation of IL-15 is critical for the preservation of allergen-induced airway hyperresponsiveness (AHR), airway resistance and compliance in response to methacholine. Airway inflammation, AHR, resistance and compliance were assessed in IL-15-deficient mice and IL-15 overexpressed mice in allergen-induced murine model of asthma. Lung histological analysis for eosinophils by anti-MBP immunostaining, Goblet cells hyperplasia by PAS staining, cytokines and chemokine levels by qPCR and ELISA analyses. Herein, we made a novel observation that IL-15 deficiency promotes baseline airway resistance in naïve mice. Moreover, rIL-15 delivery to the lung downregulates expression of inflammatory cytokines, and improves allergen-induced AHR, resistance and compliance. These observations were further validated in DOX-inducible CC-10-IL-15 transgenic mice. DOX exposed Aspergillus extract challenged CC-10-IL-15 bitransgenic mice exhibited significantly reduced levels of inflammatory cytokines (IL-4, IL-5, IL-13) and goblet cell hyperplasia. Airway obstruction, including AHR and resistance was diminished in allergen challenged DOX exposed compare to no-DOX exposed CC-10-IL-15 bitransgenic mice. Mechanistically, we observed that IL-15-induced protection of airway obstruction is associated with the induced IL-10-producing regulatory CD4+CD25+Foxp3+ T cells. We report our novel finding that IL-15 has a potent inhibitory effect on the airway obstruction that occurs in response to environmental allergens/pollutants.

Vasoactive intestinal peptide (VIP) is shown to have a role in the esophageal sphincter contraction and relaxation, and its role in pathogenesis of eosinophil associated allergic diseases like asthma and rhinitis is reported. Therefore, we tested the hypothesis that VIP may have an important role in the eosinophils accumulation in the esophagus that promote the pathogenesis of eosinophilic esophagitis (EoE). Accordingly, we performed flow cytometer analysis for VIP receptors expression in the blood eosinophils and real time PCR for VIP transcript analysis in the biopsies of human EoE. Herein, we show that human eosinophils highly express VIP associated receptor CRTH2, not VAPC1 or VAPC2. Further, VIP mRNA and protein is induced in esophageal biopsies of human EoE compare to the normal individuals. Additionally, we show that in vitro VIP has a similar chemoattractant activity for eosinophils as eotaxin. Further, we show that in vivo CRTH2 expressed eosinophils accumulated around the VIP producing nerves in the esophageal biopsies of EoE patients. Interestingly, we also observed VIP receptor VPAC2 on mast cells and their accumulation near the nerve cells in EoE biopsies. Taken together, we show the significance of VIP and its receptors interaction in the recruitment of eosinophils and mast cells that may have an important role in promoting chronic EoE pathogenesis in human.

It is mandatory to assess the allergenic potential of genetically modified (GM) crops before their commercialization. Recently, a transgene [Calcineurin B-like (CBL) protein] has been introduced into tobacco plant to make the crop salt resistance. Therefore, it was felt necessary to assess the allergenic potential of the cbl gene product, which was introduced and expressed in Nicotiana tabacum (tobacco) plant and compared the allergenic effects with the wild-type (WT) counterpart. Bioinformatic analysis revealed that there was no significant sequence homology with known allergens. Also, no difference between the protein digestibility profiles of GM and WT tobacco was found. Rapid digestion of CBL protein (Mol Wt 35 kDa) by simulated gastric fluid (SGF) indicated reduced chances of this protein to induce allergenicity. In addition, BALB/c mice sensitized by intraperitoneal administration of WT and GM tobacco protein showed comparable levels of clinical score, specific IgE, IgG1, histamine level, similar effect on different organs as well as IgE binding proteins. These findings indicate that insertion of cbl gene in tobacco did not cause any additional allergic risk to consumer and the GM and native tobacco proteins behave similarly in both in vitro and in vivo situations even after genetic modification.

Zinc oxide nanoparticles (ZNPs) have been used in dietary supplements and may cause an immunomodulatory effect. The present study investigated the effect of ZNPs on antigen-specific immune responses in mice sensitized with the T-cell-dependent antigen ovalbumin (OVA). BALB/c mice were intraperitoneally administered ZNPs (0.25, 0.5, 1 and 3mg) once, in combination with OVA, and the serum antibodies, splenocyte reactivity and activation of antigen-presenting cells were examined. The serum levels of OVA-specific IgG1 and IgE were found significantly enhanced by treatment with ZNPs over control. An increased level of IL-2, IL-4, IL-6, IL-17 and decreased level of IL-10 and TNF-α in splenocytes administered with ZNPs were observed in comparison with control. The ZNPs and OVA-stimulated T lymphocytes showed enhanced proliferation compared with control. Macrophages and B cells showed high expression of MHC class II, whereas higher expression of CD11b in macrophages of the ZNPs and ZNPs/OVA treated groups was observed. The lungs and spleen had increased eosinophils and mast cell numbers. Also, myeloperoxidase activity in lungs was found to be increased by 2.5-fold in the case of ZNPs and 3.75-fold increase in ZNPs/OVA, whereas in intestine, there was significant increase in both the groups. Increased expression of the genes for GATA-3, SOCS-3, TLR-4, IL-13 and IL-5 in the intestine was observed. Collectively, these data indicate that systemic exposure to a single administration of ZNPs could enhance subsequent antigen-specific immune reactions, including the serum production of antigen-specific antibodies, and the functionality of T cells.

Red kidney bean (Phaseolus vulgaris L.), a protein rich legume, is consumed globally due to its delicacy. This study was aimed to purify, characterize and assess allergenicity of one of its clinically relevant allergens, later identified as phaseolin. This study was carried out using clinical, in vivo and ex vivo approaches. Phaseolin, an abundant protein of red kidney bean, was purified by column chromatography and reverse-phase-HPLC techniques and characterized by peptide mass fingerprinting. The IgE immunoblotting using red kidney bean allergic patients sera showed phaseolin as a major IgE binding protein of red kidney bean. Phaseolin treated mice demonstrated enhanced levels of specific IgE and IgG1, mouse mast cell protease-1, mRNA expressions of IL-4, IL-5, IL-13 and GATA-3 in the lungs, spleen and intestine along with anaphylactic symptoms indicative of allergic responses. Further, flow cytometry analysis and immunohistochemical studies indicated increased levels of IL-4, IL-5, IL-13 and GATA-3, respectively as compared to controls. The level of Foxp3 was found suppressed in the intestine of phaseolin treated mice when compared to the control. Further, phaseolin treated mice showed positive results in type 1 skin test. Bone marrow derived mast cells (BMMCs) and rat basophilic leukemia (RBL-2H3) cells showed enhanced release of allergic mediators like β-hexosaminidase, histamine, cysteinyl leukotrienes and prostaglandin D2. Taken together, phaseolin was found to possess characteristics of a potential allergen that may lead to hypersensitivity responses in the susceptible individuals and this may be one of the major proteins responsible for allergenicity of red kidney bean.

Red kidney bean (Phaseolus vulgaris L.) is one the most commonly consumed legumes that requires an in depth understanding of its allergenicity. Therefore, the aim of this study was to explore the allergenicity of red kidney bean proteins following oral exposure in BALB/c mice and elucidate the levels of Th1/Th2 transcription factors induced by red kidney bean proteins in rat basophilic leukemia cells (RBL-2H3 cells) passively sensitized with the sera of red kidney bean sensitized mice. Red kidney bean proteins showed enhanced levels of total and specific IgE, anaphylactic symptoms, thymic stromal lymphopoietin (TSLP) and peritoneal albumin over control. Enhanced release of β-hexosaminidase along with up regulated expressions of GATA-3, STAT-6, T-bet, c-MAF and NFAT were observed in the RBL-2H3 cells exposed with red kidney bean proteins when compared to that of the controls. Taken together, exposure of red kidney bean proteins may cause allergic symptoms in mice and the ambivalent effect on Th2/Th1 transcription factors in RBL-2H3 cells.

Red kidney bean (Phaseolus vulgaris L.), a commonly consumed bean has been reported to induce allergic reactions in susceptible individuals. Phytohemagglutinins (PHAs, mainly PHA-P) contribute a major proportion of red kidney bean seeds. However, their roles in red kidney bean induced allergic reactions are still to be explored. This study was carried out to understand the role of PHAs in allergic manifestations using BALB/c mice and cultures of splenocyte, RBL-2H3 cells as well as bone marrow mast cells (BMMCs). Also, the characterization of allergic components from PHA-P was studied by LC-MS/MS. Enhanced levels of specific IgE and IgG1, clinical scores, cytokines and chemokines, β-hexosaminidase, histamine, cysteinyl leukotriene, prostaglandin D2 and abrupt histological changes in the intestine, lung and spleen indicated a pivotal role of PHA-P in red kidney bean allergy. Further, LC-MS/MS study revealed two IgE binding components of PHA-P as PHA-L and PHA-E. Enhanced specific IgE/IgG1 and β-hexosaminidase level elucidated the possible role of PHA-L and PHA-E in allergic manifestations. Furthermore, in the presence of IgE inhibitor piceatannol, reduced β-hexosaminidase release to some extent was noticed. The up regulated expression of GATA-3 and T-bet expression was observed in PHA-L as well as PHA-E groups. Taken together, this study revealed the fact that allergenicity potential of red kidney bean may get augmented due to the presence of different phytohemagglutinins. Biological significance Although food allergy is an immune provocation induced mainly by dietary allergenic protein components of the food, the role of dietary lectins in the food induced allergic manifestations cannot be ruled out. Here we provide the systematic evidences about the allergenic potential of PHAs and further disclosed the culprit components as PHA-L and PHA-E. It is an important finding that the PHA-L and PHA-E can cause allergic manifestations via not only the IgE mediated pathway but also the non-IgE mediated allergic reactions as evident by the Th1/Th2 cytokines and transcription factors. Further, the PHA-L seems to be more allergenic than the PHA-E. This article is part of a Special Issue entitled: Translational plant proteomics.

Food allergy is an immune provocation induced by certain food in susceptible individuals. Most of the food allergic manifestations are evident in the individual having impaired oral tolerance. In spite of worldwide prevalence, there is no permanent cure of food allergy. Food allergic reactions are complex immunological events that comprises of several immune molecules like IgE, IL-4, IL-13 and T-cells, therefore, researchers are trying to pick the correct molecule to find out pivotal therapeutic solutions. Being a key regulatory molecule in suppressing T-cells functional activities, cytotoxic T-cell lymphocyte antigen-4 (CTLA-4) or cluster of differentiation-152 (CD-152) has contributed a novel and revolutionary dimension toward therapeutic research of several diseases. This review focuses on different immunological and mechanistic perspectives of CTLA-4 in correlation with food allergy.

The purpose of this review is to collate current knowledge and recent advances in molecular mechanism behind the immediate type hypersensitivity of foods. Food allergy is a growing concern of human health in developed as well as developing countries now days. Food allergic reactions are mostly IgE mediated and also known as immediate type hypersensitivity or type I reaction. This review encompasses a wide range of molecular events during IgE mediated reactions like primary exposure of allergens, processing of allergens by antigen presenting cells, role of transcription factors like GATA-3, STAT-6, NF-AT, c-maf, c-kit and NF-κB, Treg cells, toll like receptors, cytokines and chemokines, class switch to IgE, FceR1 receptor, priming of IgE on mast cells or basophils, signaling events followed by secondary exposure of allergens, degranulation and release of mediators like leukotrienes, histamines, prostaglandins, β-hexosaminidase and ultimately anaphylaxis. This review may be helpful to beginners as well as experts working in the field of allergy and immunology because of the stepwise explanations of molecular mechanisms involved in IgE mediated reactions.