Venu Gangur

Chemokines in health and disease

Chemokines belong to a large family of structurally related proteins that play a pivotal role in immune system development and deployment. While a large number of chemokines (approximately 50) and their receptors (approximately 20) have been identified from humans or mice, only a few are known in domestic veterinary species. Recent data implicate CXCL8 (old name, IL-8), CXCL10 (old name, IP-10) (both CXC chemokines) and CCL2 (old name, MCP-1) (a CC chemokine) in veterinary infections, inflammatory diseases or reproduction. There is compelling evidence for neutrophil targeting chemokines such as CXCL8, in ovine bacterial mastitis, bovine pneumonic pasturellosis and equine chronic obstructive pulmonary disease (COPD). Monocyte and lymphocyte targeting chemokines appear to play a role in caprine arthritis encephalitis (CCL2) and canine endotoxemia (CXCL10). Interestingly CCL2 is considered a missing link between hormonal and cellular control of luteolysis. On the other hand, canine cardiovascular conditions are associated with overexpression of CCL2 and CXCL8. Furthermore, a number of veterinary viral pathogens encode chemokine/chemokine receptor like molecules or chemokine binding proteins that may help viruses to evade the immune system. Here, we provide an overview of the chemokine system and critically evaluate the current literature implicating chemokines in veterinary pathophysiology. Furthermore, we highlight promising areas for further research and discuss how and why chemokine antagonists are viewed as next generation anti-inflammatory drugs for the 21st century.

Sesame allergy : a growing food allergy of global proportions?

OBJECTIVE To present an up-to-date synopsis on the global prevalence, natural history, nature of allergens, and immune mechanisms of sesame allergy. DATA SOURCES We performed a literature search using the PubMed database. We obtained information on regulatory issues from the Web pages of respective agencies. STUDY SELECTION The PubMed search was performed using the algorithm sesame AND allergy. Date restriction was not used, and only articles in English were considered. The articles obtained were screened for additional references to work not obtained in the initial search. Each article was analyzed, and a pooled source of published information was generated. RESULTS Evidence was found for increased reporting of sesame allergy during the past 5 decades, with reports mostly from developed countries. Clinically, most sesame allergy was presented in at least 2 major forms: (1) immediate hypersensitivity, often expressed as systemic anaphylaxis, associated with positive skin prick test and/or IgE antibody test results to sesame proteins with some cross-reactivity with other foods, and (2) delayed hypersensitivity to lignin-like compounds in sesame oil clinically expressed as contact allergic dermatitis. There were a few cases of immediate hypersensitivity to sesame with negative skin prick test and/or IgE antibody test results that were confirmed by oral challenge tests. CONCLUSIONS Sesame allergy is a significant, serious, and growing problem. Evidence exists of the ability of protein and oil components of sesame to trigger immediate hypersensitivity via IgE antibody and delayed hypersensitivity via cell-mediated immune responses, respectively.

Review: Immune Markers in Breast Milk and Fetal and Maternal Body Fluids: A Systematic Review of Perinatal Concentrations

Breastfeeding represents the continued exposure of the infant to the maternal immune environment. Uterine, perinatal, and postnatal exposure to immune factors may contribute to an infant’s risk of developing immune-mediated disorders, including allergies. A PubMed search was conducted to review studies in humans and analyze concentrations of immune markers (TGF-β, IFN-γ, eotaxin, CCL5, CXCL10, TNF-α, MCP-1, IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, sCD14, sIgA, IgG4, IgM) found in maternal serum, amniotic fluid, cord serum, colostrum, transition and mature milk. Concentrations of immune markers showed large variations across samples and studies. Reports documented conflicting results. Small sample sizes, differences in population characteristics, inconsistent sample collection times, and various sample collection and measurement methods may have led to wide variations in the concentrations of immune markers. Studies analyzing the associations between immune markers in maternal fluids and infant allergies remain inconclusive because of gaps in knowledge and a lack of standardized methods.

An Adjuvant-Free Mouse Model of Tree Nut Allergy Using Hazelnut as a Model Tree Nut

Background: Tree nut allergy, a major group of food allergy, is often linked to fatal or near-fatal systemic anaphylaxis. Currently, an adjuvant-free mouse model to study tree nut hypersensitivity is unavailable. Here we tested the hypothesis that transdermal exposure to hazelnut, a model tree nut, without the use of an adjuvant is sufficient to sensitize mice for immediate hypersensitivity reaction to oral hazelnut challenge. Methods: BALB/c mice were repeatedly exposed to hazelnut protein via the transdermal route and systemic allergic and anaphylactic responses were studied. Results: Transdermal exposure to hazelnut protein elicited robust systemic IgE response in a dose-dependent manner with immunological memory. Oral challenge of transdermally sensitized mice with hazelnut protein resulted in immediate (30 min after the challenge) clinical signs of systemic anaphylaxis as measured by significant clinical scores and drop in rectal temperature. Clinical hypersensitivity reaction was associated with severe pathological changes in the small intestine. Hazelnut-allergic but not control mice exhibited in vivo activation of GATA-3 and hazelnut-driven recall IL-4, IL-5 and IL-13 response by splenocytes, thus elucidating the underlying mechanism of hazelnut allergy development in this model. Conclusions: These data suggest that (1) transdermal exposure to hazelnut protein is sufficient to activate the key immune pathways necessary for sensitizing mice for clinical immediate hypersensitivity reactions and (2) this mouse model may be useful for further basic and applied studies on tree nut allergy, especially because it does not depend on an adjuvant for eliciting immediate hypersensitivity reactions to nut protein.

Allergic and Anaphylactic Response to Sesame Seeds in Mice: Identification of Ses i 3 and Basic Subunit of 11s Globulins as Allergens

Background: Allergy to sesame seeds is an emerging food allergy of a serious nature due to a high risk of systemic anaphylaxis. Although a mouse model to study sesame anaphylaxis is desirable, currently it is not available. Here, using a transdermal exposure model system, we tested the hypothesis that sesame seed elicits IL-4-associated IgE antibody response with consequent clinical sensitization in mice. Methods: Groups of BALB/c mice were exposed to sesame seed extract or saline or a control food (vanilla bean extract) by transdermal applications. Systemic IgE, IgG1 and IgG2a antibody responses were examined using preoptimized ELISA. Type 2 and type 1 cytokine responses were evaluated by ex vivo antigen-mediated activation of spleen cells. Clinical response to oral sesame challenge was studied. Western blot and N-terminal amino acid sequence analyses were performed to identify the sesame allergens. Results: Transdermal exposure to sesame elicited robust IgE and IgG1 but very little IgG2a antibody responses. IgE response to transdermal exposure in two high-IgE responder mice strains with disparate MHC confirmed the intrinsic allergenicity of sesame seed. Transdermal sensitization was associated with activation of IL-4 but not IFN-γ. Furthermore, oral exposure to sesame resulted in clinical signs of systemic anaphylaxis. Western blot and sequence analysis identified four allergens including Ses i 3 and the basic subunit of 11s globulins. Conclusion: These data argue that transdermal exposure to sesame seed can result in IL-4 activation, IgE response and clinical sensitization for systemic anaphylaxis.

Development of an Adjuvant-Free Cashew Nut Allergy Mouse Model

Background: Cashew nut allergy is an emerging food allergy with a high risk of systemic anaphylaxis. Currently, an adjuvant-free animal model to study cashew nut allergy is not available. Methods: BALB/c mice were exposed to cashew nut protein using a transdermal sensitization protocol that does not use adjuvant. Systemic IgE antibody response, systemic anaphylaxis to oral challenge and allergen-driven, spleen-cell, type-2 cytokine responses were studied. Results: Transdermal exposure to cashew nut resulted in a significant dose-dependent allergic response. Oral challenge of sensitized mice with cashew resulted in severe signs of systemic anaphylaxis and a significant hypothermia. Spleen cell culture with cashew nut protein resulted in allergen-driven IL-4, IL-5 and IL-13 responses only in sensitized but not in saline control mice. Conclusions: These data demonstrate that (i) transdermal exposure to cashew nut protein elicits a robust IgE response leading to clinical sensitization of mice for systemic anaphylaxis to oral cashew nut challenge; (ii) cashew nut is a potent activator of type-2 cytokines, thus explaining the mechanism of cashew allergy, and (iii) this mouse model may be useful for further basic and preclinical studies on cashew nut allergy.

An ELISA-based method for measurement of food-specific IgE antibody in mouse serum: an alternative to the passive cutaneous anaphylaxis assay

Passive cutaneous anaphylaxis (PCA) assay has been a gold standard method to measure allergen-specific IgE antibody (ASIgE Ab) levels in allergy mouse models. Many factors including stringent guidelines for laboratory animal use make PCA a difficult choice. Therefore, alternative methods are needed that can be readily applied for measurement of specific IgE antibody levels in mouse serum. Herein we describe a novel ELISA-based method that is more sensitive in comparison to PCA, IgE isotype-specific (because it has little cross-reactivity with IgG1 or IgG2a isotype) and highly reproducible (<10% inter- or intra-assay variation). Furthermore, we demonstrate the utility of this assay to measure specific IgE Ab against a variety of food extracts including chicken egg, peanut, almond, filbert/hazelnut and sweet potato. These findings are of particular interest to those who are seeking (i) to measure food-extract-specific IgE antibody in animal models and (ii) an alternative to the animal-based PCA method to measure mouse IgE antibodies.

An adjuvant-free mouse model to evaluate the allergenicity of milk whey protein

Milk allergy is the most common type of food allergy in humans with the potential for fatality. An adjuvant-free mouse model would be highly desirable as a preclinical research tool to develop novel hypoallergenic or nonallergenic milk products. Here we describe an adjuvant-free mouse model of milk allergy that uses transdermal sensitization followed by oral challenge with milk protein. Groups of BALB/c mice were exposed to milk whey protein via a transdermal route, without adjuvant. Systemic IgG1 and IgE antibody responses to transdermal exposure as well as systemic anaphylaxis and hypothermia response to oral protein challenge were studied. Transdermal exposure resulted in a time- and dose-dependent induction of significant IgE and IgG1 antibody responses. Furthermore, oral challenge of sensitized mice resulted in significant clinical symptoms of systemic anaphylaxis within 1 h and significant hypothermia at 30 min postchallenge. To study the underlying mechanism, we examined allergen-driven spleen cell T-helper 2 cytokine (IL-4) responses. There was a robust dose- and time-dependent activation of memory IL-4 responses in allergic mice but not in healthy control mice. These data demonstrate for the first time a novel transdermal sensitization followed by oral challenge mouse model of milk allergy that does not use adjuvant. It is expected that this model may be used not only to study mechanisms of milk allergy, but also to evaluate novel milk products for allergenic potential and aid in the production of hypo- or nonallergenic milk products.

Sex Disparity in Food Allergy: Evidence from the PubMed Database

Food allergies are potentially fatal immune-mediated disorders that are growing globally. The relationship between sex and food allergy remains incompletely understood. Here we tested the hypothesis that, should sex influence the clinical response to food allergens, this would be reflected by a sex disparity in published studies of food allergy. We performed a systematic search of the PubMed literature for IgE-mediated allergy to 11 allergenic foods of international regulatory importance. No date restriction was used and only articles in English were considered. Of the 4744 articles retrieved, 591 met the inclusion criteria representing 17528 subjects with food allergies. Whereas among children with food allergies, 64.35% were males and 35.65% were females (male/female ratio, 1.80), among adults 34.82% were males and 65.18% were females (male/female ratio, 0.53). Consequently, these data argue that there is need for further investigation to define the role of sex in the pathogenesis of food allergy.

CCR3 and CXCR3 as Drug Targets for Allergy: Principles and Potential

Atopic disorders include a range of conditions such as allergic asthma, -rhinitis, -conjunctivitis, -dermatitis, food and drug allergies and anaphylaxis. Induction of T helper (Th)-2 immune response with consequent IgE dependent eosinophil, basophil and mast cell mediated tissue damage is the characteristic feature of allergies. The mechanism underlying this unique and long appreciated feature of allergy is being elucidated at the molecular level with advances in our knowledge of the chemokine system. Thus, chemokines that target CCR3 in concert with Th2 cytokines appear to play a pathogenic role in allergy. In contrast, chemokines that target CXCR3 in concert with Th1 cytokine appear to play a beneficial role. Accordingly, inhibiting CCR3/Th2 pathway using CCR3 antagonists is viewed as a potentially useful strategy for anti-allergy drug development. In contrast, the idea of using CXCR3 agonists to inhibiting allergic response by promoting CXCR3/Th1 pathway faces serious concerns of their potential pro-inflammatory activities in vivo. In this article we have critically evaluated the literature examining the principle and potential of this anti-allergy drug development strategy including a summary of various compounds that are under investigation.