Interplay between Foxp3+ regulatory T cells (Treg) and dendritic cells (DCs) maintains immunologic tolerance, but the effects of each cell on the other are not well understood. We report that polyclonal CD4+Foxp3+ Treg cells induced ex vivo with transforming growth factor beta (TGFβ) (iTreg) suppress a lupus-like chronic graft-versus-host disease by preventing the expansion of immunogenic DCs and inducing protective DCs that generate additional recipient CD4+Foxp3+ cells. The protective effects of the transferred iTreg cells required both interleukin (IL)-10 and TGFβ, but the tolerogenic effects of the iTreg on DCs, and the immunosuppressive effects of these DCs were exclusively TGFβ-dependent. The iTreg were unable to tolerize Tgfbr2-deficient DCs. These results support the essential role of DCs in ‘infectious tolerance’ and emphasize the central role of TGFβ in protective iTreg/DC interactions in vivo.
regulatory T cells; dendritic cells; TGFβ; graft-versus-host disease
antihistamines; diphenhydramine; cetirizine; acute food allergic reactions; oral food challenges
Studies have demonstrated that IgE-binding cross-reactive epitopes between shrimp, cockroach and house dust mite tropomyosins can account for the presence of detectable IgE to shrimp in people who have cockroach and dust mite allergies.
We investigated the correlation between IgE-mediated sensitization to shrimp, cockroach, and dust mite in relation to allergen exposure in inner-city children.
Five hundred and four serum samples from the National Cooperative Inner City Asthma Study (NCICAS) were evaluated for specific IgE to shrimp and the results were compared to specific IgE to cockroach (Blattella germanica) and dust mite (Dermatophagoides farinae). Associations between IgE sensitization to these allergens and environmental exposures were determined.
There was a strong positive correlation between shrimp, cockroach, and dust mite IgE levels. High exposure to cockroach (Bla g) in the home, particularly in the bedroom and television room, was significantly correlated with higher shrimp and cockroach IgE levels. In contrast, high exposure to dust mite in the home was highly correlated with IgE to D.farinae, but not with shrimp IgE levels. There is a synergistic relationship between cockroach IgE and exposure in predicting shrimp IgE levels.
For children with evidence of IgE-mediated sensitization to cockroach and shrimp, having high exposure to cockroach in the home can contribute to higher shrimp IgE levels, which may not correlate with clinical reactivity. Further patient evaluations with clinical histories of shrimp exposure and reactions as well as oral food challenges would have to be performed to confirm these findings.
cockroach; dust mite; shrimp; tropomyosin; cross-reactivity
Both nature and induced regulatory T (Treg) lymphocytes are potent regulators of autoimmune and allergic disorders. Defects in endogenous Treg cells have been reported in patients with allergic asthma, suggesting that disrupted Treg cell-mediated immunological regulation may play an important role in airway allergic inflammation. In order to determine whether adoptive transfer of induced Treg cells generated in vitro can be used as an effective therapeutic approach to suppress airway allergic inflammation, exogenously induced Treg cells were infused into ovalbumin-sensitized mice prior to or during intranasal ovalbumin challenge. The results showed that adoptive transfer of induced Treg cells prior to allergen challenge markedly reduced airway hyperresponsiveness, eosinophil recruitment, mucus hyper-production, airway remodeling, and IgE levels. This effect was associated with increase of Treg cells (CD4+FoxP3+) and decrease of dendritic cells in the draining lymph nodes, and with reduction of Th1, Th2, and Th17 cell response as compared to the controls. Moreover, adoptive transfer of induced Treg cells during allergen challenge also effectively attenuate airway inflammation and improve airway function, which are comparable to those by natural Treg cell infusion. Therefore, adoptive transfer of in vitro induced Treg cells may be a promising therapeutic approach to prevent and treat severe asthma.
IgE-mediated food sensitization and allergy are common in inner city children, even in the absence of reported clinical reactivity. Clinicians caring for this population should maintain a high index of suspicion for food allergy.
food allergy; sensitization; inner city
Purpose of review
To consider the possible links between food allergy and asthma.
Food allergy and asthma coexist in many children, and recent studies demonstrate that having these co-morbid conditions increases the risk for morbidity. Children with food allergies and asthma are more likely to have near-fatal or fatal allergic reactions to food and more likely to have severe asthma.
Although a causal link has not been determined, increased awareness of the heightened risks of having both of these common childhood conditions, and good patient/parent education and management of both conditions, can lead to improved outcomes..
food; allergy; asthma; prevalence
Egg is one of the most important allergens in childhood feeding, and egg allergy can pose quality of life concerns. A clear clinical history and the detection of egg white specific IgE will confirm the diagnosis of IgE-mediated reactions. Non-IgE-mediated symptoms such as in eosinophilic diseases of the gut might also be observed. Egg avoidance and education regarding the treatment of allergic reactions are the cornerstones of management of egg allergy. In this review, we discuss epidemiology, risk factors, diagnosis, treatment and natural history of egg allergy.
Egg; allergy; food; children; hypersensitivity; IgE; ovomucoid; ovalbumin
Food allergies affect up to 6% of young children and 3%–4% of adults. They encompass a range of disorders that may be IgE and/or non-IgE mediated, including anaphylaxis, pollen food syndrome, food-protein–induced enterocolitis syndrome, food-induced proctocolitis, eosinophilic gastroenteropathies, and atopic dermatitis. Many complex host factors and properties of foods are involved in the development of food allergy. With recent advances in the understanding of how these factors interact, the development of several novel diagnostic and therapeutic strategies is underway and showing promise.
Food allergy is a common and increasing health concern in westernized countries. No effective treatment is available and accidental ingestion can be life threatening. Food allergy herbal formula-2 (FAHF-2) blocks peanut anaphylaxis in a murine model of peanut-induced anaphylaxis. It was found to be safe, and well tolerated in an acute phase I study of food allergic patients.
To assess the safety of FAHF-2 in an extended phase I clinical trial and determine potential effects on peripheral blood basophils from food allergic patients.
Patients in an open-label study received 3.3 grams (6 tablets) of FAHF-2 three times a day for 6 months. Vital signs, physical examinations, laboratory data, pulmonary function tests and electrocardiographic data were acquired at baseline and at 2 month intervals. During the course of the study, basophil activation and basophil and eosinophil numbers were evaluated using CCR3/ CD63 staining and flow cytometry.
Of eighteen patients enrolled, 14 completed the study. No significant drug-associated differences in laboratory parameters, pulmonary function studies, or electrocardiographic findings before and after treatment were found. There was a significant reduction (p<.010) in basophil CD63 expression in response to ex vivo stimulation at month 6. There was also a trend towards a reduction of eosinophil and basophil numbers after treatment.
FAHF-2 was safe, well-tolerated, and had an inhibitory effects on basophils in an extended phase I clinical study. A controlled phase II study is warranted.
FAHF-2 was safe, well-tolerated and inhibited basophils numbers and activation in a 6 month clinical trial for food allergic patients. FAHF-2 may provide a safe immunotherapeutic option for food allergic patients.
FAHF-2 was safe and well-tolerated in a six-month phase-I open label clinical trial for food allergy patients. Immunological beneficial effects of FAHF-2 were decreased basophil numbers and inhibition of activation.
Food allergy; FAHF-2; Basophil activation
Coronary artery disease is the most common cause of death in the Western world, and being married decreases the risk of death from cardiovascular causes. We aimed to determine whether marital status was a predictor of the duration of chest pain endured by patients with acute myocardial infarction before they sought care and whether the patient’s sex modified the effect.
We conducted a retrospective, population-based cohort analysis of patients with acute myocardial infarction admitted to 96 acute care hospitals in Ontario, Canada, from April 2004 to March 2005. We excluded patients who did not experience chest pain. Using multivariable regression analyses, we assessed marital status in relation to delayed presentation to hospital (more than six hours from onset of pain), both overall and stratified by sex. In patients who reported the exact duration of chest pain, we assessed the effect of marital status on the delay in seeking care.
Among 4403 eligible patients with acute myocardial infarction, the mean age was 67.3 (standard deviation 13.6) years, and 1486 (33.7%) were women. Almost half (2037 or 46.3%) presented to a hospital within two hours, and 3240 (73.6%) presented within six hours. Overall, 75.3% (2317/3079) of married patients, 67.9% (188/277) of single patients, 68.5% (189/276) of divorced patients and 70.8% (546/771) of widowed patients presented within six hours of the onset of chest pain. Being married was associated with lower odds of delayed presentation (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.30–0.71, p < 0.001) relative to being single. Among men, the OR was 0.35 (95% CI 0.21–0.59, p < 0.001), whereas among women the effect of marital status was not significant (OR 1.36, 95% CI 0.49–3.73, p = 0.55).
Among men experiencing acute myocardial infarction with chest pain, being married was associated with significantly earlier presentation for care, a benefit that was not observed for married women. Earlier presentation for medical care appears to be one reason for the observed lower risk of cardiovascular death among married men, relative to their single counterparts.
It has been documented all-trans retinoic acid (atRA) promotes the development of TGF-β-induced CD4+Foxp3+ regulatory T cells (iTreg) that play a vital role in the prevention of autoimmune responses, however, molecular mechanisms involved remain elusive. Our objective, therefore, was to determine how atRA promotes the differentiation of iTregs.
Addition of atRA to naïve CD4+CD25− cells stimulated with anti-CD3/CD28 antibodies in the presence of TGF-β not only increased Foxp3+ iTreg differentiation, but maintained Foxp3 expression through apoptosis inhibition. atRA/TGF-β-treated CD4+ cells developed complete anergy and displayed increased suppressive activity. Infusion of atRA/TGF-β-treated CD4+ cells resulted in the greater effects on suppressing symptoms and protecting the survival of chronic GVHD mice with typical lupus-like syndromes than did CD4+ cells treated with TGF-β alone. atRA did not significantly affect the phosphorylation levels of Smad2/3 and still promoted iTreg differentiation in CD4+ cells isolated from Smad3 KO and Smad2 conditional KO mice. Conversely, atRA markedly increased ERK1/2 activation, and blockade of ERK1/2 signaling completely abolished the enhanced effects of atRA on Foxp3 expression. Moreover, atRA significantly increased histone methylation and acetylation within the promoter and conserved non-coding DNA sequence (CNS) elements at the Foxp3 gene locus and the recruitment of phosphor-RNA polymerase II, while DNA methylation in the CNS3 was not significantly altered.
We have identified the cellular and molecular mechanism(s) by which atRA promotes the development and maintenance of iTregs. These results will help to enhance the quantity and quality of development of iTregs and may provide novel insights into clinical cell therapy for patients with autoimmune diseases and those needing organ transplantation.
BAFF, in addition to promoting B cell survival and differentiation, may affect T cells. The objective of this study was to determine the effect of BAFF on Th17 cell generation and its ramifications for the Th17 cell-driven disease, EAE.
Th17 cells were increased in BAFF-Tg B6 (B6.BTg) mice and decreased in B6.Baff−/− mice. Th17 cells in B6.Baff−/− mice bearing a BAFF Tg (B6.Baff−/−.BTg mice) were identical to those in B6.BTg mice, indicating that membrane BAFF is dispensable for Th17 cell generation as long as soluble BAFF is plentiful. In T + non-T cell criss-cross co-cultures, Th17 cell generation was greatest in cultures containing B6.BTg T cells and lowest in cultures containing B6.Baff−/− T cells, regardless of the source of non-T cells. In cultures containing only T cells, Th17 cell generation followed an identical pattern. CD4+ cell expression of CD126 (IL-6R α chain) was increased in B6.BTg mice and decreased in B6.Baff−/− mice, and activation of STAT3 following stimulation with IL-6 + TGF-β was also greatest in B6.BTg cells and lowest in B6.Baff−/− cells. EAE was clinically and pathologically most severe in B6.BTg mice and least severe in B6.Baff−/− mice and correlated with MOG35–55 peptide-induced Th17 cell responses.
Collectively, these findings document a contribution of BAFF to pathogenic Th17 cell responses and suggest that BAFF antagonism may be efficacious in Th17 cell-driven diseases.
Recent studies have demonstrated that plasticity of naturally occurring CD4+Foxp3+ regulatory T cells (nTregs) may account for their inability to control chronic inflammation in established autoimmune diseases. All-trans retinoic acid (atRA), the active derivative of vitamin A, has been demonstrated to promote Foxp3+ Treg differentiation and suppress Th17 development. In this study, we report a vital role of atRA in sustaining the stability and functionality of nTregs in the presence of IL-6. We found that nTregs treated with atRA were resistant to Th17 and other Th cell conversion and maintained Foxp3 expression and suppressive activity in the presence of IL-6 in vitro. atRA decreased IL-6R expression and signaling by nTregs. Of interest, adoptive transfer of nTregs even from arthritic mice treated with atRA suppressed progression of established collagen-induced arthritis. We suggest that nTregs treated with atRA may represent a novel treatment strategy to control established chronic immune-mediated inflammatory diseases.
Whereas TGF-β is essential for the development of peripherally induced Foxp3+ regulatory T cells (iTreg cells) and Th17 cells, the intracellular signaling mechanism by which TGF-β regulates development of both cell subsets is less understood. In this study, we report that neither Smad2 nor Smad3 gene deficiency abrogates TGF-β–dependent iTreg induction by a deacetylase inhibitor trichostatin A in vivo, although the loss of the Smad2 or Smad3 gene partially reduces iTreg induction in vitro. Similarly, SMAD2 and SMAD3 have a redundant role in development of Th17 in vitro and in experimental autoimmune encephalomyelitis. In addition, ERK and/or JNK pathways were shown to be involved in regulating iTreg cells, whereas the p38 pathway predominately modulated Th17 and experimental autoimmune encephalomyelitis induction. Therefore, selective targeting of these intracellular TGF-β signaling pathways during iTreg and Th17 cell development might lead to the development of therapies in treating autoimmune and other chronic inflammatory diseases.
The utility of [18F]FPBM (2-(2′-((dimethylamino)methyl)-4′-(3-[18F]-fluoropropoxy)phenylthio)benzenamine), a selective serotonin transporter (SERT) tracer, and [18F]AV-133 ((+)-2-Hydroxy-3-isobutyl-9-(3-fluoropropoxy)-10-methoxy-1,2,3,4,6,7-hexahydro-11bH-benzo[a]quinolizine), a selective vesicular monoamine transporter 2 (VMAT2) tracer, were tested in the 6-hydroxydopamine (6-OHDA) unilateral lesioned rat model.
PET imaging of three 6-OHDA unilateral lesioned male Sprague Dawley rats (rats #1-3) were performed with [18F]FPBM and [18F]AV-133 to examine whether changes in SERT and VMAT2 binding, respectively, could be detected in the brain. The brains of the three rats were then removed and examined by in vitro autoradiography with [18F]FPBM and the dopamine transporter ligand, [125I]IPT, for confirmation.
PET image analysis showed varying levels of SERT binding reduction (rat #1 = −11%, rat #2 = −4%, rat #3 = −43%; n = 2) and a clear and definitive loss of VMAT2 binding (rat #1 = −87%, rat #2 = −72%, and rat #3 = −91%; n = 1) in the left striatum when compared to the right (non-lesioned side) striatum. The results from PET imaging were corroborated with quantitative in vitro autoradiography. Rats treated with a selective serotonin toxin (PCA, p-chloroamphetamine) showed a significant reduction of uptake in the cortex and hypothalamus regions of the brain.
The preliminary data suggest that [18F]FPBM and [18F]AV-133 may be useful for the examination of serotonergic and dopaminergic neuron integrity, respectively, in the living brain.
brain imaging; radioligand; SERT; VMAT2; Parkinson’s Disease
Food allergies affect 6% of children and 3% to 4% of adults in the United States. Although several studies have examined the prevalence of food allergy, little information is available regarding the prevalence of multiple food allergies. Estimates of prevalence of people allergic to multiple foods is difficult to ascertain because those with allergy to one food may avoid additional foods for concerns related to cross-reactivity, positive tests, or prior reactions, or they may be reluctant to introduce foods known to be common allergens. Diagnosis relies on an accurate history and selective IgE testing. It is important to understand the limitations of the available tests and the role of cross-reactivity between allergens. Allergen avoidance and readily accessible emergency medications are the cornerstones of management. In addition, a multidisciplinary approach to management of individuals with multiple food allergies may be needed, as avoidance of several food groups can have nutritional, developmental, and psychosocial consequences.
Multiple food allergy; IgE; Sensitization; Cross-reactivity; Diagnosis; Allergy management
Results from large-scale epitope mapping using peptide microarray have been shown to correlate with clinical features of milk allergy.
We sought to assess IgE and IgG4 epitope diversity and IgE affinity in different clinical phenotypes of milk allergy and identify informative epitopes that may be predictive of clinical outcomes of milk allergy.
Forty-one subjects were recruited from a larger study on the effects of ingesting heat-denatured milk proteins in milk-allergic individuals. Using food challenges, subjects were characterized as clinically reactive to all forms of milk (n = 17), tolerant to heated milk (HM) products (n = 16), or outgrown their milk allergy (n = 8). Eleven non-milk allergic, healthy volunteers served as controls. Peptide microarray was performed using the previously published protocol.
Milk allergic subjects had increased epitope diversity as compared to those who outgrew their allergy. HM tolerant subjects had IgE binding patterns similar to those who had outgrown their allergy, but IgG4 binding patterns that were more similar to the allergic group. Binding to higher numbers of IgE peptides was associated with more severe allergic reactions during challenge. There was no association between IgG4 peptides and clinical features of milk allergy. Using a competitive peptide microarray assay, allergic patients demonstrated a combination of high and low affinity IgE binding whereas HM tolerant subjects and those who had outgrown their milk allergy had primarily low affinity binding.
Greater IgE epitope diversity and higher affinity as determined by peptide microarray were associated with clinical phenotypes and severity of milk allergy.
Milk allergy; Peptide microarray; IgE pitope; IgE affinity; IgG4 epitope
Food allergy is a common and serious health problem. A new herbal product, called food allergy herbal formula 2 (FAHF-2), has been demonstrated to have a high safety profile and potent long-term efficacy in a murine model of peanut-induced anaphylaxis.
To evaluate the safety and tolerability of FAHF-2 in patients with food allergy.
In this randomized, double-blinded, placebo-controlled, dose escalation, phase 1 trial, patients received 1 of 3 doses of FAHF-2 or placebo: 2.2 g (4 tablets), 3.3 g (6 tablets), or 6.6 g (12 tablets) 3 times a day for 7 days. Four active and 2 placebo patients were treated at each dose level. Vital signs, physical examination results, laboratory data, pulmonary function test results, and electrocardiogram data were monitored. Immunomodulatory studies were also performed.
Nineteen food allergic participants were included in the study. Two patients (1 in the FAHF-2 group and 1 in the placebo group) reported mild gastrointestinal symptoms. One patient withdrew from the study because of an allergic reaction that was unlikely related to the study medication. No significant differences were found in vital signs, physical examination results, laboratory data, pulmonary function test results, and electrocardiogram data obtained before and after treatment visits. Significantly decreased interleukin (IL) 5 levels were found in the active treatment group after 7 days. In vitro studies of peripheral blood mononuclear cells cultured with FAHF-2 also demonstrated a significant decrease in IL-5 and an increase in culture supernatant interferon γ and IL-10 levels.
FAHF-2 appeared to be safe and well tolerated in patients with food allergy.
TGF-β plays an important role in the induction of regulatory T cells (Treg) and maintenance of immunologic tolerance, but whether other members of TGF-β superfamily act together or independently to achieve this effect is poorly understood. Although others have reported that the bone morphogenetic proteins (BMP) and TGF-β have similar effects on the development of thymocytes and T cells, in this study, we report that members of the BMP family, BMP-2 and BMP-4, are unable to induce non-regulatory T cells to become Foxp3+ Treg. Neutralization studies with Noggin have revealed that BMP-2/4 and the BMP receptor signaling pathway is not required for TGF-β to induce naive CD4+CD25- cells to express Foxp3; however, BMP-2/4 and TGF-β have a synergistic effect on the induction of Foxp3+ Treg. BMP-2/4 affects non-Smad signaling molecules including phosphorylated ERK and JNK, which could subsequently promote the differentiation of Foxp3+ Treg induced by TGF-β. Data further advocate that TGF-β is a key signaling factor for Foxp3+ Treg development. In addition, the synergistic effect of BMP-2/4 and TGF-β indicates that the simultaneous manipulation of TGF-β and BMP signaling might have considerable effects in the clinical setting for the enhancement of Treg purity and yield.
BMP; TGF-β; Foxp3; regulatory T cells
Protective CD4+CD25+ regulatory T cells bearing the Forkhead Foxp3 transcription factor can now be divided into three subsets: Endogenous thymus-derived cells, those induced in the periphery, and another subset induced ex-vivo with pharmacological amounts of IL-2 and TGF-β. Unfortunately, endogenous CD4+CD25+ regulatory T cells are unstable and can be converted to effector cells by pro-inflammatory cytokines. Although protective Foxp3+CD4+CD25+ cells resistant to proinflammatory cytokines have been generated in mice, in humans this result has been elusive. Our objective, therefore, was to induce human naïve CD4+ cells to become stable, functional CD25+ Foxp3+ regulatory cells that were also resistant to the inhibitory effects of proinflammatory cytokines.
The addition of the vitamin A metabolite, all-trans retinoic acid (atRA) to human naïve CD4+ cells suboptimally activated with IL-2 and TGF-β enhanced and stabilized FOXP3 expression, and accelerated their maturation to protective regulatory T cells. AtRA, by itself, accelerated conversion of naïve to mature cells but did not induce FOXP3 or suppressive activity. The combination of atRA and TGF-β enabled CD4+CD45RA+ cells to express a phenotype and trafficking receptors similar to natural Tregs. AtRA/TGF-β-induced CD4+ regs were anergic and low producers of IL-2. They had potent in vitro suppressive activity and protected immunodeficient mice from a human-anti-mouse GVHD as well as expanded endogenous Tregs. However, treatment of endogenous Tregs with IL-1β and IL-6 decreased FOXP3 expression and diminished their protective effects in vivo while atRA-induced iTregs were resistant to these inhibitory effects.
We have developed a methodology that induces human CD4+ cells to rapidly become stable, fully functional suppressor cells that are also resistant to proinflammatory cytokines. This methodology offers a practical novel strategy to treat human autoimmune diseases and prevent allograft rejection without the use of agents that kill cells or interfere with signaling pathways.
Survivors of anterior MI are at increased risk for stroke with predilection to form ventricular thrombus. Commonly patients are discharged on dual antiplatelet therapy. Given the frequency of early coronary reperfusion and risk of bleeding, it remains uncertain whether anticoagulation offers additional utility. We examined the effectiveness of anticoagulation therapy for the prevention of stroke after anterior MI.
Methods and Findings
We performed a population-based cohort analysis of 10,383 patients who survived hospitalization for an acute MI in Ontario, Canada from April 1, 1999 to March 31, 2001. The primary outcome was four-year ischemic stroke rates compared between anterior and non-anterior MI patients. Risk factors for stroke were assessed by multivariate Cox proportional-hazards analysis. Warfarin use was determined at discharge and followed for 90 days among a subset of patients aged 66 and older (n = 1483). Among the 10,383 patients studied, 2,942 patients survived hospitalization for an anterior MI and 20% were discharged on anticoagulation therapy. Within 4 years, 169 patients (5.7%) were admitted with an ischemic stroke, half of which occurred within 1-year post-MI. There was no significant difference in stroke rate between anterior and non-anterior MI patients. The use of warfarin up to 90 days was not associated with stroke protection after anterior MI (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.37–1.26). The use of angiotensin-converting-enzyme inhibitors (HR, 0.65; 95% CI, 0.44–0.95) and beta-blockers (HR, 0.60; 95% CI, 0.41–0.87) were associated with a significant decrease in stroke risk. There was no significant difference in bleeding-related hospitalizations in patients who used warfarin for up to 90 days post-MI.
Many practitioners still consider a large anterior-wall MI as high risk for potential LV thrombus formation and stroke. Among a cohort of elderly patients who survived an anterior MI there was no benefit from the use of warfarin up to 90 days post-MI to prevent ischemic stroke. Our data suggests that routine anticoagulation of patients with anterior-wall MI may not be indicated. Prospective randomized trials are needed to determine the optimal antithrombin strategy for preventing this common and serious adverse outcome.
The peptide microarray is a novel assay which facilitates high-throughput screening of peptides with a small quantity of sample.
We sought to use overlapping peptides of milk allergenic proteins as a model system to establish a reliable and sensitive peptide microarray-based immunoassay for large scale epitope mapping of food allergens.
A milk peptide microarray was developed using commercially synthesized peptides (20-mers, 3 offset) covering the primary sequences of αs1-, αs2-, β-, and κ-caseins, and β-lactoglobulin. Conditions for printing and immunolabeling were optimized using a serum pool of five milk-allergic patients. Reproducibility of the milk peptide microarray was evaluated using replicate arrays immunolabeled with the serum pool, whereas specificity and sensitivity were assessed using serial dilution of the serum pool and a peptide inhibition assay.
Our results show that epitopes identified by the peptide microarray were mostly consistent with those identified previously by SPOT membrane technology, but with specific binding to a few newly identified epitopes of milk allergens. Data from replicate arrays were reproducible (R≥0.92) regardless of printing lots, immunolabeling and serum pool batches. Using the serially diluted serum pool, we confirmed that IgE antibody binding detected in the array was specific. Peptide inhibition of IgE binding to the same peptide and overlapping peptides further confirmed the specificity of the array.
A reliable peptide microarray was established for large scale IgE epitope mapping of milk allergens and this robust technology could be applied for epitope mapping of other food allergens.
Epitope mapping; peptide microarray; allergy; milk allergen
There are no ideal ways to identify and isolate viable and purified Foxp3+ regulatory T cells so far. Here we developed a novel procedure for the isolation of highly purified Foxp3+ cells using flow cytometry. This method relies on an identification and sorting of the lymphoblast cell population identified on a scatter plot using flow cytometry. We confirmed that greater than 98% of the cells sorted using this technique expressed Foxp3 and displayed a potent suppressive activity. This method provides a valuable tool for the study of the T regulatory cell biology and their therapeutic manipulation.
Foxp3; TGF-β; regulatory T cells
Food allergies are adverse immune reactions to food proteins that affect up to 6% of children and 3-4% of adults. A wide range of symptoms can occur depending on whether IgE or non-IgE mediated mechanism are involved. Many factors influence the development of oral tolerance, including route of exposure, genetics, age of the host, and allergen factors. Advances have been made in the understanding of how these factors interact in the pathophysiology of food allergy. Currently, the mainstay of treatment for food allergies is avoidance and ready access to emergency medications. However, with the improved understanding of tolerance and advances in characterization of food allergens, several therapeutic strategies have been developed and are currently being investigated as potential treatments and/or cures for food allergy.
food hypersensitivity; allergy; anaphylaxis; oral tolerance; immunotherapy