A novel druglike spleen tyrosine kinase binder prevents anaphylactic shock when administered orally

TMT-Based Quantitative Proteomic Analysis Reveals Downregulation of ITGAL and Syk by the Effects of Cycloastragenol in OVA-Induced Asthmatic Mice

BACKGROUND

Cycloastragenol (CAG) has been reported to alleviate airway inflammation in ovalbumin- (OVA-) induced asthmatic mice. However, its specific mechanisms remain unclear.

OBJECTIVE

This study is aimed at investigating the effects of CAG on asthma, comparing its efficacy with dexamethasone (DEX), and elucidating the mechanism of CAG's regulation.

METHODS

The asthma mouse model was induced by OVA. CAG at the optimal dose of 125 mg/kg was given every day from day 0 for 20-day prevention or from day 14 for a 7-day treatment. We observed the preventive and therapeutic effects of CAG in asthmatic mice by evaluating the airway inflammation, AHR, and mucus secretion. Lung proteins were used for TMT-based quantitative proteomic analysis to enunciate its regulatory mechanisms.

RESULTS

The early administration of 125 mg/kg CAG before asthma happened prevented asthmatic mice from AHR, airway inflammation, and mucus hypersecretion, returning to nearly the original baseline. Alternatively, the administration of CAG during asthma also had the same therapeutic effects as DEX. The proteomic analysis revealed that the therapeutical effects of CAG were associated with 248 differentially expressed proteins and 3 enriched KEGG pathways. We then focused on 3 differentially expressed proteins (ITGAL, Syk, and Vav1) and demonstrated that CAG treatment downregulated ITGAL, Syk, and Vav1 by quantitative real-time PCR, western blot analysis, and immunohistochemical staining.

CONCLUSION

These findings suggest that CAG exerts preventive and protective effects on asthma by inhibiting ITGAL, Syk, and the downstream target Vav1.

Targeting the splicing isoforms of spleen tyrosine kinase affects the viability of colorectal cancer cells

Spleen tyrosine kinase (Syk) expression have been both positively and negatively associated with tumorigenesis. Our goal was to evaluate the contribution of Syk and its two splice variants, full length Syk (L) and short isoform Syk (S), in the tumor biology of colorectal cancer cells (CRC). The analysis of Syk expression in primary human colorectal tumors, as well as the analysis of TCGA database, revealed a high Syk mRNA expression score in colorectal cancer tumors, suggesting a tumor promotor role of Syk in CRC. Our analysis showed that Syk (L) isoform is highly expressed in the majority of the tumor tissues and that it remains expressed in tumors in which global Syk expression is downregulated, suggesting the dependence of tumors to Syk (L) isoform. We also identified a small cluster of tumor tissues, which express a high proportion of Syk (S) isoform. This specific cluster is associated with overexpressed genes related to translation and mitochondria, and down regulated genes implicated in the progression of mitosis. For our functional studies, we used short hairpin RNA tools to target the expression of Syk in CRC cells bearing the activating K-Ras (G13D) mutation. Our results showed that while global Syk knock down increases cell proliferation and cell motility, Syk (L) expression silencing affects the viability and induces the apoptosis of the cells, confirming the dependence of cells on Syk (L) isoform for their survival. Finally, we report the promising potential of compound C-13, an original non-enzymatic inhibitor of Syk isolated in our group. In vitro studies showed that C-13 exerts cytotoxic effects on Syk-positive CRC cells by inhibiting their proliferation and their motility, and by inducing their apoptosis, while Syk-negative cell lines viability was not affected. Moreover, the oral and intraperitoneal administration of C-13 reduced the tumor growth of CRC DLD-1 cells xenografts in Nude mice in vivo.

Exploration of the Molecular Mechanism of FUZI (Aconiti Lateralis Radix Praeparata) in Allergic Rhinitis Treatment Based on Network Pharmacology

FUZI (Aconiti Lateralis Radix Praeparata) is a traditional Chinese medicine herb used extensively for nourishing yang (regarded as the positive, male universal force), which is critical in treatment of allergic rhinitis. In this paper, FUZI was explored based on network pharmacology. The active components of FUZI were screened out, its protein targets were assessed, and the protein interaction network map was built with the differential protein of allergic rhinitis, as an attempt to determine the critical targets of FUZI for treating allergic rhinitis. Subsequently, DAVID was employed to explore the biological function and pathway enrichment to determine the biological pathway of FUZI for treating allergic rhinitis.

As suggested by the results, FUZI is likely to affect the inhibition of inflammation and the regulation of immunity, probably reducing the incidence of allergic rhinitis, or alleviating nasal discomfort attributed to allergic inflammation. The targets and pathways of FUZI for treating allergic rhinitis assessed by network pharmacology provided a direction for our subsequent studies and may be a novel therapeutic target.

Pharmacophore approaches in protein kinase inhibitors design

Protein kinases constitute a superfamily of therapeutic targets for a number of human and animal diseases that include more than 500 members accordingly to sequencing data of the human genome. The well characterized nature of protein kinases makes them excellent targets for drug development. Pharmacophore approaches have become one of the major tools in the area of drug discovery. Application of pharmacophore modeling approaches allows reducing of expensive overall cost associated with drug development project. Pharmacophore models are important functional groups of atoms in the proper spatial position for interaction with target protein. Various ligand-based and structure-based methods have been developed for pharmacophore model generation. Despite the successes in pharmacophore models generation these approaches have not reached their full capacity in application for drug discovery. In the following review, we summarize the published data on pharmacophore models for inhibitors of tyrosine protein kinases (EGFR, HER2, VEGFR, JAK2, JAK3, Syk, ZAP-70, Tie2) and inhibitors of serine/threonine kinases (Clk, Dyrk, Chk1, IKK2, CDK1, CDK2, PLK, JNK3, GSK3, mTOR, p38 MAPK, PKB). Here, we have described the achievements of pharmacophore modeling for protein kinase inhibitors, which provide key points for further application of generated pharmacophore hypotheses in virtual screening, de novo design and lead optimization.

Twenty-first century mast cell stabilizers

Mast cell stabilizing drugs inhibit the release of allergic mediators from mast cells and are used clinically to prevent allergic reactions to common allergens. Despite the relative success of the most commonly prescribed mast cell stabilizer, disodium cromoglycate, in use for the preventative treatment of bronchial asthma, allergic conjunctivitis and vernal keratoconjunctivitis, there still remains an urgent need to design new substances that are less expensive and require less frequent dosing schedules. In this regard, recent developments towards the discovery of the next generation of mast cell stabilizing drugs has included studies on substances isolated from natural sources, biological, newly synthesized compounds and drugs licensed for other indications. The diversity of natural products evaluated range from simple phenols, alkaloids, terpenes to simple amino acids. While in some cases their precise mode of action remains unknown it has nevertheless sparked interest in the development of synthetic derivatives with improved pharmacological properties. Within the purely synthetic class of inhibitors, particular attention has been devoted to the inhibition of important signalling molecules including spleen TK and JAK3. The statin class of cholesterol-lowering drugs as well as nilotinib, a TK inhibitor, are just some examples of clinically used drugs that have been evaluated for their anti-allergic properties. Here, we examine each approach under investigation, summarize the test data generated and offer suggestions for further preclinical evaluation before their therapeutic potential can be realized.

In-cell intrabody selection from a diverse human library identifies C12orf4 protein as a new player in rodent mast cell degranulation

The high specificity of antibodies for their antigen allows a fine discrimination of target conformations and post-translational modifications, making antibodies the first choice tool to interrogate the proteome. We describe here an approach based on a large-scale intracellular expression and selection of antibody fragments in eukaryotic cells, so-called intrabodies, and the subsequent identification of their natural target within living cell. Starting from a phenotypic trait, this integrated system allows the identification of new therapeutic targets together with their companion inhibitory intrabody. We applied this system in a model of allergy and inflammation. We first cloned a large and highly diverse intrabody library both in a plasmid and a retroviral eukaryotic expression vector. After transfection in the RBL-2H3 rat basophilic leukemia cell line, we performed seven rounds of selection to isolate cells displaying a defect in FcεRI-induced degranulation. We used high throughput sequencing to identify intrabody sequences enriched during the course of selection. Only one intrabody was common to both plasmid and retroviral selections, and was used to capture and identify its target from cell extracts. Mass spectrometry analysis identified protein RGD1311164 (C12orf4), with no previously described function. Our data demonstrate that RGD1311164 is a cytoplasmic protein implicated in the early signaling events following FcεRI-induced cell activation. This work illustrates the strength of the intrabody-based in-cell selection, which allowed the identification of a new player in mast cell activation together with its specific inhibitor intrabody.

Pathogenic intracellular and autoimmune mechanisms in urticaria and angioedema

Urticaria and angioedema are common disorders. Chronic urticaria is defined as lasting longer than 6 weeks. Causes of chronic urticaria fall into the following categories: physical, allergic, hereditary, autoimmune, and idiopathic. Basophils and mast cells are the primary effector cells responsible for clinical symptoms and signs. These cells produce and secrete a variety of mediators including histamine, leukotrienes, prostaglandins, cytokines, chemokines, and other pro-inflammatory mediators. This leads to vasodilation, fluid exudation, increased vascular permeability, and accumulation of additional secondary inflammatory cells. Two mechanisms have been investigated as possibly contributing to the pathogenesis of chronic urticaria. One is the development of autoantibodies to FcεRI or IgE on mast cells and basophils. This appears to be responsible for 30-50 % of cases. The other is dysregulation of intracellular signaling pathways involving Syk, SHIP-1, or SHIP-2 in basophils and mast cells. The primary treatment for chronic urticaria is to treat the underlying pathology, if any can be identified. Otherwise, in idiopathic cases, H1 antihistamines, H2 antihistamines, antileukotrienes, and corticosteroids constitute the main pharmacologic treatment modalities. In severe and recalcitrant cases of chronic and autoimmune urticaria, immunosuppressive drugs have been used, most commonly cyclosporin. More recent experimental studies have also suggested that omalizumab, an anti-IgE therapy, may be of benefit. Currently, inhibitors of Syk are also being developed and tested in the laboratory and in animal models. As our understanding of the pathogenesis of idiopathic urticaria increases, development of additional drugs targeting these pathways may provide relief for the significant physical and psychological morbidity experienced by patients with this disorder.

Blockade of Syk ameliorates the development of murine sclerodermatous chronic graft-versus-host disease

BACKGROUND

Murine sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) is a model for human Scl-cGVHD and systemic sclerosis (SSc). Syk is expressed in most of hematopoietic cells, fibroblasts, and endothelial cells. Syk is a protein tyrosine kinase that has an important role in transmitting signals from a variety of cell surface receptors.

OBJECTIVE

This study aims to investigate the effect of R788 (fostamatinib sodium), an oral prodrug that is rapidly converted to a potent inhibitor of Syk, R406, on Scl-cGVHD.

METHODS

R788 was orally administered twice a day to allogeneic recipients from day 14 to day 42 after bone marrow transplantation (BMT). In vitro, proliferation of GVHD-derived CD4(+) T cells and CD11b(+) cells was analyzed by R406.

RESULTS

Allogeneic BMT increased Syk phosphorylation in T, B, and CD11b(+) cells. The administration of R788 attenuated severity and fibrosis of Scl-cGVHD. The elevated expressions of CXCR4 on T cells, B cells, and CD11b(+) cells were significantly down-regulated by R788 treatment. R788 reduced memory CD4(+) T cells (CD44(hi)CD62L(-)CD4(+)). R406 inhibited proliferation of GVHD CD4(+) T cells and CD11b(+) cells in vitro. In addition, R788 treatment, inhibited proliferation of CD11b(+) cells in Scl-cGVHD mice. R788 treatment also reduced skin mRNA expressions of MCP-1, MIP-1α, IFN-γ, IL-13, IL-17A, and TGF-β1, but not influenced RANTES, CXCL12, and TFN-α.

CONCLUSION

Blockade of Syk suppressed migration factor of immune cells and antigen-specific memory CD4(+) T cells and proliferation and activation of GVHD CD4(+) T cells and CD11b(+) cells. The current studies suggested that Syk inhibitor is a potential candidate for use in treating patients with Scl-cGVHD and SSc.

Curcumin inhibits the activation of immunoglobulin e-mediated mast cells and passive systemic anaphylaxis in mice by reducing serum eicosanoid and histamine levels

Curcumin is naturally occurring polyphenolic compound found in turmeric and has many pharmacological activities. The present study was undertaken to evaluate anti-allergic inflammatory activity of curcumin, and to investigate its inhibitory mechanisms in immunoglobulin E (IgE)/Ag-induced mouse bone marrow-derived mast cells (BMMCs) and in a mouse model of IgE/Ag-mediated passive systemic anaphylaxis (PSA). Curcumin inhibited cyclooxygenase-2 (COX-2) dependent prostaglandin D₂ (PGD₂) and 5-lipoxygenase (5-LO) dependent leukotriene C₄ (LTC₄) generation dose-dependently in BMMCs. To probe the mechanism involved, we assessed the effects of curcumin on the phosphorylation of Syk and its downstream signal molecules. Curcumin inhibited intracellular Ca²⁺ influx via phospholipase Cγ1 (PLCγ1) activation and the phosphorylation of mitogen-activated protein kinases (MAPKs) and the nuclear factor-κB (NF-κB) pathway. Furthermore, the oral administration of curcumin significantly attenuated IgE/Ag-induced PSA, as determined by serum LTC₄, PGD₂, and histamine levels. Taken together, this study shows that curcumin offers a basis for drug development for the treatment of allergic inflammatory diseases.

Molecular diagnosis of peanut allergy

Peanut allergy prevalence has increased in developed countries over the last few decades in the frame of the allergy epidemics, currently affecting 1-2% of children. While less frequent in developing countries, its prevalence is rising as these countries adopt a more westernized lifestyle. There is no curative treatment for peanut allergy at present so patient management relies on peanut avoidance, which requires an accurate diagnosis. Recent progress in peanut allergy diagnosis was made with the introduction of component resolved diagnosis that allows the assessment of IgE specific to individual peanut allergens. Component-resolved diagnosis needs to be interpreted in the context of clinical data but overall increases the diagnostic accuracy, as described in the typical cases that we present. Novel diagnostic tools have been proposed recently, such as the basophil activation test, mRNA expression and resonance magnetic evaluation of biomarkers.

Applying ligands profiling using multiple extended electron distribution based field templates and feature trees similarity searching in the discovery of new generation of urea-based antineoplastic kinase inhibitors

This study provides a comprehensive computational procedure for the discovery of novel urea-based antineoplastic kinase inhibitors while focusing on diversification of both chemotype and selectivity pattern. It presents a systematic structural analysis of the different binding motifs of urea-based kinase inhibitors and the corresponding configurations of the kinase enzymes. The computational model depends on simultaneous application of two protocols. The first protocol applies multiple consecutive validated virtual screening filters including SMARTS, support vector-machine model (ROC = 0.98), Bayesian model (ROC = 0.86) and structure-based pharmacophore filters based on urea-based kinase inhibitors complexes retrieved from literature. This is followed by hits profiling against different extended electron distribution (XED) based field templates representing different kinase targets. The second protocol enables cancericidal activity verification by using the algorithm of feature trees (Ftrees) similarity searching against NCI database. Being a proof-of-concept study, this combined procedure was experimentally validated by its utilization in developing a novel series of urea-based derivatives of strong anticancer activity. This new series is based on 3-benzylbenzo[d]thiazol-2(3H)-one scaffold which has interesting chemical feasibility and wide diversification capability. Antineoplastic activity of this series was assayed in vitro against NCI 60 tumor-cell lines showing very strong inhibition of GI₅₀ as low as 0.9 uM. Additionally, its mechanism was unleashed using KINEX™ protein kinase microarray-based small molecule inhibitor profiling platform and cell cycle analysis showing a peculiar selectivity pattern against Zap70, c-src, Mink1, csk and MeKK2 kinases. Interestingly, it showed activity on syk kinase confirming the recent studies finding of the high activity of diphenyl urea containing compounds against this kinase. Allover, the new series, which is based on a new kinase scaffold with interesting chemical diversification capabilities, showed that it exhibits its “emergent” properties by perturbing multiple unexplored kinase pathways.

Established and emerging trends in computational drug discovery in the structural genomics era

Bioinformatics and chemoinformatics approaches contribute to hit discovery, hit-to-lead optimization, safety profiling, and target identification and enhance our overall understanding of the health and disease states. A vast repertoire of computational methods has been reported and increasingly combined in order to address more and more challenging targets or complex molecular mechanisms in the context of large-scale integration of structure and bioactivity data produced by private and public drug research. This review explores some key computational methods directly linked to drug discovery and chemical biology with a special emphasis on compound collection preparation, virtual screening, protein docking, and systems pharmacology. A list of generally freely available software packages and online resources is provided, and examples of successful applications are briefly commented upon.

Selection for intrabody solubility in mammalian cells using GFP fusions

Single-chain antibody fragments (scFv) expressed in the cytoplasm of mammalian cells, also called intrabodies, have many applications in functional proteomics. These applications are, however, limited by the aggregation-prone behaviour of many intrabodies. We show here that two scFv with highly homologous sequences and comparable soluble expression levels in Escherichia coli cytoplasm have different behaviours in mammalian cells. When over-expressed, one of the scFv aggregates in the cytoplasm whereas the second one is soluble and active. When expressed at low levels, using a retroviral vector, as a fusion with the green fluorescent protein (GFP) the former does not form aggregates and is degraded, resulting in weakly fluorescent cells, whereas the latter is expressed as a soluble protein, resulting in strongly fluorescent cells. These data suggest that the GFP signal can be used to evaluate the soluble expression of intrabodies in mammalian cells. When applied to a subset of an E.coli-optimised intrabody library, we showed that the population of GFP+ cells contains indeed soluble mammalian intrabodies. Altogether, our data demonstrate that the requirements for soluble intrabody expression are different in E.coli and mammalian cells, and that intrabody libraries can be directly optimised in human cells using a simple GFP-based assay.

Tyrosine kinase syk non-enzymatic inhibitors and potential anti-allergic drug-like compounds discovered by virtual and in vitro screening

In the past decade, the spleen tyrosine kinase (Syk) has shown a high potential for the discovery of new treatments for inflammatory and autoimmune disorders. Pharmacological inhibitors of Syk catalytic site bearing therapeutic potential have been developed, with however limited specificity towards Syk. To address this topic, we opted for the design of drug-like compounds that could impede the interaction of Syk with its cellular partners while maintaining an active kinase protein. To achieve this challenging task, we used the powerful potential of intracellular antibodies for the modulation of cellular functions in vivo, combined to structure-based in silico screening. In our previous studies, we reported the anti-allergic properties of the intracellular antibody G4G11. With the aim of finding functional mimics of G4G11, we developed an Antibody Displacement Assay and we isolated the drug-like compound C-13, with promising in vivo anti-allergic activity. The likely binding cavity of this compound is located at the close vicinity of G4G11 epitope, far away from the catalytic site of Syk. Here we report the virtual screen of a collection of 500,000 molecules against this new cavity, which led to the isolation of 1000 compounds subsequently evaluated for their in vitro inhibitory effects using the Antibody Displacement Assay. Eighty five compounds were selected and evaluated for their ability to inhibit the liberation of allergic mediators from mast cells. Among them, 10 compounds inhibited degranulation with IC₅₀ values ≤ 10 µM. The most bioactive compounds combine biological activity, significant inhibition of antibody binding and strong affinity for Syk. Moreover, these molecules show a good potential for oral bioavailability and are not kinase catalytic site inhibitors. These bioactive compounds could be used as starting points for the development of new classes of non-enzymatic inhibitors of Syk and for drug discovery endeavour in the field of inflammation related disorders.

Spleen tyrosine kinases: biology, therapeutic targets and drugs

Spleen tyrosine kinase (Syk) is an intriguing protein tyrosine kinase involved in signal transduction in a variety of cell types, and its aberrant regulation is associated with different allergic disorders and antibody-mediated autoimmune diseases such as rheumatoid arthritis, asthma and allergic rhinitis. Syk also plays an important part in the uncontrolled growth of tumor cells, particularly B cells. For these reasons, Syk is considered one of the most interesting biological targets of the last decade, as proved by the great number of papers and patents published, and the possibility of treating these pathologies by means of Syk kinase inhibitors has led to a great interest from the pharmaceutical and biotech industry.

The tyrosine kinase network regulating mast cell activation

Mast cell mediator release represents a pivotal event in the initiation of inflammatory reactions associated with allergic disorders. These responses follow antigen-mediated aggregation of immunoglobulin E (IgE)-occupied high-affinity receptors for IgE (Fc epsilon RI) on the mast cell surface, a response which can be further enhanced following stem cell factor-induced ligation of the mast cell growth factor receptor KIT (CD117). Activation of tyrosine kinases is central to the ability of both Fc epsilon RI and KIT to transmit downstream signaling events required for the regulation of mast cell activation. Whereas KIT possesses inherent tyrosine kinase activity, Fc epsilon RI requires the recruitment of Src family tyrosine kinases and Syk to control the early receptor-proximal signaling events. The signaling pathways propagated by these tyrosine kinases can be further upregulated by the Tec kinase Bruton's tyrosine kinase and downregulated by the actions of the tyrosine Src homology 2 domain-containing phosphatase 1 (SHP-1) and SHP-2. In this review, we discuss the regulation and role of specific members of this tyrosine kinase network in KIT and Fc epsilon RI-mediated mast cell activation.

Advances in mechanisms of asthma, allergy, and immunology in 2008

This review summarizes selected articles appearing in 2008 in the Journal. Articles chosen include those improving our understanding of mechanisms of allergic diseases by focusing on human basophil, mast cell, and eosinophil biology; IgE and its high-affinity receptor on various cells; novel properties of omalizumab; airways remodeling; and genetics. Articles from other journals have been included to supplement the topics presented.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2008

This review highlights some of the research advances in anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects and in allergic skin disease that were reported in the Journal in 2008. Key epidemiologic observations include a rise in anaphylaxis in a population-based study and lower rates of peanut allergy in Israel, where infants consume peanut early compared with the United Kingdom, where dietary introduction is generally delayed. Advances in food allergy diagnosis include IgE epitope mapping that discloses the likelihood and severity of allergy; studies correlating likelihood of clinical reactivity on the basis of food-specific IgE to sesame, peanut, milk, and tree nuts; and an observation that a low baseline angiotensin-converting enzyme level may be associated with having pharyngeal edema during a reaction. Molecular, immunologic, and genetic studies are discerning pathways that are key in development of food allergy, identifying new modalities to interrupt mast cell degranulation, and elucidating risks associated with penicillin allergy. Regarding treatment, clinical studies show a majority of children with milk and egg allergy tolerate these proteins in modest amounts when they are extensively heated in baked goods, and studies show promise for oral immunotherapy to treat milk allergy and sublingual immunotherapy for honey bee venom hypersensitivity. The importance of skin barrier dysfunction has continued to be highlighted in the pathophysiology of atopic dermatitis (AD). Research has also continued to identify immunologic defects that contribute to the propensity of patients with AD to develop viral and bacterial infection. New therapeutic approaches to AD, urticaria, and angioedema have been reported including use of probiotics, biologics, vitamin D, and skin barrier creams.

Pharmacophore modeling study based on known spleen tyrosine kinase inhibitors together with virtual screening for identifying novel inhibitors

In this investigation, chemical features based 3D pharmacophore models were developed based on the known inhibitors of Spleen tyrosine kinase (Syk) with the aid of hiphop and hyporefine modules within catalyst. The best quantitative pharmacophore model, Hypo1, was used as a 3D structural query for retrieving potential inhibitors from chemical databases including Specs, NCI, MayBridge, and Chinese Nature Product Database (CNPD). The hit compounds were subsequently subjected to filtering by Lipinski's rule of five and docking studies to refine the retrieved hits. Finally 30 compounds were selected from the top ranked hit compounds and conducted an in vitro kinase inhibitory assay. Six compounds showed a good inhibitory potency against Syk, which have been selected for further investigation.

Structural biology contributions to tyrosine kinase drug discovery

Successful kinase inhibitor drug discovery relies heavily on the structural knowledge of the interaction of inhibitors with the target. Structural biology of kinases and in particular of tyrosine kinases has given detailed insights into the intrinsic flexibility of the catalytic domain and has provided a rational basis for obtaining selective inhibitors. Important progress has been made recently, both in academia and in the pharmaceutical industry, with respect to solving structures of inactive, multidomain or protein-protein complexes of kinases, which helps our understanding of the dynamics of regulation of kinase activity. This leads to a better understanding of how mutations lead to activation of kinases and resistance, in addition to providing opportunities for novel modes of targeting kinases.

Towards a cure for food allergy

Over the past two decades, food allergies have become both more prevalent and long lasting. This burgeoning problem has not been met with any therapeutic options to date, and patients must attempt to avoid known allergenic foods and treat any allergic reactions with 'as-needed' medications. There are a number of promising emerging therapeutic modalities for food allergy, including allergen-specific and allergen non-specific immunotherapeutic approaches. Although the allergen-specific approaches have some distinct differences, they all attempt to induce tolerance by exposing the patient to an allergen via the mucosal route (oral tolerance induction). Allergen non-specific approaches include biologics to suppress free total IgE levels (e.g. anti-IgE antibody) or to induce more general immune suppression (Chinese herbal medication).