A multi-center assessment to compare residual allergenicity of partial hydrolyzed whey proteins in a murine model for cow's milk allergy - Comparison to the single parameter guinea pig model

INTRODUCTION

This 4-center study is part of a project to validate a food allergy murine model for safety testing of hydrolyzed infant formulas.

AIM

The aim of the current multi-center experiment was to evaluate the residual allergenicity of three partial hydrolyzed whey proteins (pWH) in a multiple-parameter cow's milk allergy murine model and to compare to the classically used guinea pig model. Previous work showed differences in the magnitude of the allergic response to whey between centers. To get a first insight in the effect of housing on the robustness of the mouse model, microbiota composition of non-sensitized mice was analyzed and compared between centers.

METHODS

Mice were sensitized intragastrically (i.g.) with whey, pWH or eWH using cholera toxin as an adjuvant. In mice, whey-IgE/IgG1, acute allergic symptoms were determined upon whey challenge. Guinea pigs were orally sensitized ad libitum via the drinking water (day 0-37) and challenged intravenously with whey on day 49. The microbial composition in fecal samples was determined in non-sensitized mice in all 4 research centers before and after conduct of the study.

RESULTS

Elevated levels of whey-IgG1 were detected in whey-sensitized mice in all centers. Except for pWH-A in center 4, we observed elevated levels of whey-IgE in whey-sensitized mice and mice sensitized with pWH-A, -B, -C. Center 2 was excluded from further analysis because of non-significant IgE levels in the positive control. In contrast to whey-mice, pWH-A treated mice showed no acute skin response, mMCP-1 release or change in body temperature upon whey challenge in all centers, which corresponds with the absence of anaphylactic shock symptoms in both the mouse and guinea pig model. pWH-B and -C induced anaphylactic shock symptoms in the guinea-pig and mice whereas results on the remaining allergic outcomes in mice were inconclusive. No differences in microbiota composition were measured in response to the challenge and Microbiota composition depended on the location of the centers.

CONCLUSIONS

Both animal models showed comparable results on the residual allergenicity of partial hydrolyzed whey proteins, but none of the centers was able to differentiate between the residual sensitizing capacities of the pWH-B and -C based on a single elicitation parameter in the murine model. Differences in microbiota composition might contribute to the robustness of the food allergy murine model. For a well-balanced prediction on the potential allergenicity of hydrolyzed infant formulas a multiple murine parameter model is suggested to decrease the risk of false positive or false negative results. A future challenge is to develop an overall scoring system for proper risk assessment, taking all parameters into account.

Altered microbial community structure and metabolism in cow's milk allergic mice treated with oral immunotherapy and fructo-oligosaccharides

Previously, we showed enhanced efficacy of oral immunotherapy (OIT) using fructo-oligosaccharides (FOS, prebiotics) added to the diet of cow's milk allergic mice indicated by a reduction in clinical symptoms and mast cell degranulation. Prebiotics are fermented by gut bacteria, affecting both bacterial composition and availability of metabolites (i.e. short-chain fatty acids (SCFA)). It is thus far unknown which microbial alterations are involved in successful outcomes of OIT with prebiotic supplementation for the treatment of food allergy. To explore potential changes in the microbiota composition and availability of SCFA induced by OIT+FOS. C3H/HeOuJ mice were sensitised and received OIT with or without a FOS supplemented diet. After three weeks, faecal samples were collected to analyse gut microbiota composition using 16S rRNA sequencing. SCFA concentrations were determined in cecum content. FOS supplementation in sensitised mice changed the overall microbial community structure in faecal samples compared to sensitised mice fed the control diet (P=0.03). In contrast, a high level of resemblance in bacterial community structure was observed between the non-sensitised control mice and the OIT+FOS treated mice. OIT mice showed an increased relative abundance of the dysbiosis-associated phylum Proteobacteria compared to the OIT+FOS mice. FOS supplementation increased the relative abundance of genus Allobaculum (Firmicutes), putative butyrate-producing bacteria. OIT+FOS reduced the abundances of the genera's unclassified Rikenellaceae (Bacteroidetes, putative pro-inflammatory bacteria) and unclassified Clostridiales (Firmicutes) compared to sensitised controls and increased the abundance of Lactobacillus (Firmicutes, putative beneficial bacteria) compared to FOS. OIT+FOS mice had increased butyric acid and propionic acid concentrations. OIT+FOS induced a microbial profile closely linked to non-allergic mice and increased concentrations of butyric acid and propionic acid. Future research should confirm whether there is a causal relationship between microbial modulation and the reduction in acute allergic symptoms induced by OIT+FOS.

Mice co-administrated with partially hydrolysed whey proteins and prebiotic fibre mixtures show allergen-specific tolerance and a modulated gut microbiota

Non-breastfed infants at-risk of allergy are recommended to use a hydrolysed formula before the age of 6 months. The addition of prebiotics to this formula may reduce the allergy development in these infants, but clinical evidence is still inconclusive. This study evaluates (1) whether the exposure duration to different prebiotics alongside a partially hydrolysed whey protein (pHP) influences its' effectiveness to prevent allergy development and (2) whether the gut microbiota plays a role in this process. Mice orally sensitised with whey and/or cholera toxin were orally treated for six days before sensitization with phosphate buffered saline, whey or pHP to potentially induce tolerance. Two groups received an oligosaccharide diet only from day -7 until -2 (GFshort and GFAshort) whereas two other groups received their diets from day -15 until 37 (GFlong and GFAlong). On day 35, mice underwent an intradermal whey challenge, and the acute allergic skin response, shock score, and body temperatures were measured. At day 37, mice received whey orally and serum mouse mast cell protease-1, SLPI and whey-specific antibodies were assessed. Faecal samples were taken at day -15, -8 and 34. Feeding mice pHP alone during tolerance induction did not reduce ear swelling. The tolerance inducing mechanisms seem to vary according to the oligosaccharide-composition. GFshort, GFlong, and GFAlong reduced the allergic skin response, whereas GFAshort was not potent enough. However, in the treatment groups, the dominant Lactobacillus species decreased, being replaced by Bacteroidales family S24-7 members. In addition, the relative abundance of Prevotella was significantly higher in the GFlong, GFAshort and GFAlong groups. Co-administration of oligosaccharides and pHP can induce immunological tolerance in mice, although tolerance induction was strongest in the animals that were fed oligosaccharides during the entire protocol. Some microbial changes coincided with tolerance induction, however, a specific mechanism could not be determined based on these data.

Non-digestible oligosaccharides modulate intestinal immune activation and suppress cow's milk allergic symptoms

BACKGROUND

Cow's milk allergy is a common food allergy in childhood and no effective preventive or curative treatment is available. This study aimed at comparing single short-chain galacto- (scGOS), long-chain fructo- (lcFOS) or pectin-derived acidic oligosaccharides (pAOS) and/or mixtures of scGOS/lcFOS (GF) or scGOS/lcFOS/pAOS (GFA) to prevent or treat food allergy.

METHODS

In the preventive protocol, C3H/HeOuJ mice were fed diets containing single oligosaccharides or mixtures GF or GFA throughout the study protocol. In the treatment protocol, GF or GFA was provided for 4 wk starting after the last sensitization. The allergic skin response and anaphylaxis scores were determined, after oral challenge whey-specific immunoglobulins were measured, and qPCR for T-cell markers and Foxp3 counts using immunohistochemistry were performed on the small intestine and colon.

RESULTS

Only in the preventive setting, the GF or GFA mixture, but not the single oligosaccharides, reduced the allergic skin response and whey-IgG(1) levels in whey-sensitized mice, compared to the control diet. Both GF and GFA increased the number of Foxp3+ cells in the proximal small intestine of whey - compared to sham-sensitized mice. Expression of Th2 and Th17 mRNA markers increased in the middle part of the small intestine of whey-sensitized mice, which was prevented by GF. By contrast, GFA enhanced Tbet (Th1), IL-10 and TGF-β mRNA expression compared to GF which was maintained in the distal small intestine and/or colon.

CONCLUSIONS

Dietary supplementation with scGOS/lcFOS or scGOS/lcFOS/pAOS during sensitization, both effectively reduce allergic symptoms but differentially affect mucosal immune activation in whey-sensitized mice.

Effects of short-chain galacto- and long-chain fructo-oligosaccharides on systemic and local immune status during pregnancy

Nondigestible oligosaccharides can positively influence health via various mechanisms. During pregnancy, supplementation of nondigestible oligosaccharides has positive effects on hypertension and metabolism and may be used to ameliorate pregnancy-related metabolic disturbances. In the nonpregnant state, nondigestible oligosaccharides have been shown to induce a tolerogenic immune response mediated by T-regulatory cells. Since relatively little is known about the effects of nondigestible oligosaccharides on the immune system during pregnancy, pregnant mice were supplemented with a specific mixture of short-chain galacto- and long-chain fructo-oligosaccharides (scGOS/lcFOS; ratio 9:1). Systemic and local immune parameters were analyzed on day 18 of pregnancy. This study shows that, compared with virgin mice, scGOS/lcFOS supplementation appears to elicit a more tolerogenic immune reaction in pregnant mice and supplementation does not increase the Th1-dependent delayed type hypersensitivity response in pregnant mice as it does in virgin mice.

Galectin-9 induced by dietary synbiotics is involved in suppression of allergic symptoms in mice and humans

BACKGROUND

Prebiotic galacto- and fructo-oligosaccharides (scGOS/lcFOS) resembling non-digestible oligosaccharides in human milk reduce the development of atopic disorders. However, the underlying mechanisms are still unclear. Galectins are soluble-type lectins recognizing β-galactoside containing glycans. Galectin-9 has been shown to regulate mast cell degranulation and T-cell differentiation. In this study, the involvement of galectin-9 as a mechanism by which scGOS/lcFOS in combination with Bifidobacterium breve M-16V protects against acute allergic symptoms was investigated.

METHODS

Mice were sensitized orally to whey, while being fed with a diet containing scGOS/lcFOS and Bifidobacterium breve M-16V (GF/Bb) or a control diet. Galectin-9 expression was determined by immunohistochemistry in the intestine and measured in the serum by ELISA. T-cell differentiation was investigated in the mesenteric lymph nodes (MLN) as well as in galectin-9-exposed peripheral blood mononuclear cells (PBMC) cultures. Sera of the mice were evaluated for the capacity to suppress mast cell degranulation using a RBL-2H3 degranulation assay. In addition, in a double-blind, placebo-controlled multicenter trial, galectin-9 levels were measured in the sera of 90 infants with atopic dermatitis who received hydrolyzed formulae with or without GF/Bb.

RESULTS

Galectin-9 expression by intestinal epithelial cells and serum galectin-9 levels were increased in mice and humans following dietary intervention with GF/Bb and correlated with reduced acute allergic skin reaction and mast cell degranulation. In addition, GF/Bb enhanced T(h)1- and T(reg)-cell differentiation in MLN and in PBMC cultures exposed to galectin-9.

CONCLUSIONS

Dietary supplementation with GF/Bb enhances serum galectin-9 levels, which associates with the prevention of allergic symptoms.

Early life: gut microbiota and immune development in infancy

The immune system of infants is actively downregulated during pregnancy and therefore the first months of life represent a period of heightened susceptibility to infection. After birth, there is an age-dependent maturation of the immune system. Exposure to environmental microbial components is suggested to play an important role in the maturation process. The gastrointestinal tract is the major site of interaction between the host immune system and microorganisms, both commensal as well as potentially pathogenic. It is well established that the mammalian immune system is designed to help protect the host from invading microorganisms and other danger signals. However, recent research is emerging in the field of host-microbe interactions showing that commensal microorganisms (microbiota) are most likely one of the drivers of immune development and, in turn the immune system shapes the composition of the microbiota. Specific early microbial exposure of the gut is thought to dramatically reduce the incidence of inflammatory, autoimmune and atopic diseases further fuelling the scientific view that microbial colonisation plays an important role in regulating and fine-tuning the immune system throughout life. Therefore, the use of pre-, pro- and synbiotics may result in a beneficial microbiota composition that might have a pivotal role on the prevention of several important diseases that develop in early life such as necrotizing enterocolitis and atopic eczema.

No detectable beneficial systemic immunomodulatory effects of a specific synbiotic mixture in infants with atopic dermatitis

BACKGROUND

In a murine model of allergic inflammation, Bifidobacterium breve M-16V has been shown to reduce IL-4 and IgE by inducing IL-10 and IFN-γ. However, it remains unknown whether this strain has the same effect in humans with allergic disease.

OBJECTIVE

To determine the effects of Bifidobacterium breve M-16V combined with a prebiotic oligosaccharide mixture (synbiotic) on atopic markers, ex vivo cytokine production by peripheral blood mononuclear cells (PBMCs) and circulating regulatory T cell percentage in infants with atopic dermatitis.

METHODS

In a double-blind, placebo-controlled multi-centre trial, 90 infants with atopic dermatitis, age <7 months, were randomized to receive an infant formula with Bifidobacterium breve M-16V and a mixture of short chain galactooligosaccharides and long chain fructooligosaccharides (Immunofortis(®) ), or the same formula without synbiotics during 12 weeks. At week 0 and 12, plasma levels of IL-5, IgG1, IgG4, CTACK and TARC, ex vivo cytokine responses by PBMCs and percentage of regulatory T cells, were determined.

RESULTS

There were no significant differences between the synbiotic and the placebo group in IL-5, IgG1, IgG4, CTACK and TARC levels and ex vivo cytokine production by anti-CD3/anti-CD28-stimulated PBMCs. With allergen-specific stimuli, we found a decreased IL-12p40/70 and IL-12p70 production in response to egg allergen (P = 0.04 and P = 0.01, respectively) and decreased IL-12p70 production in response to peanut allergen (P = 0.003) in the synbiotic compared with the placebo group. Circulating regulatory T cell percentage did not significantly differ between the groups.

CONCLUSIONS AND CLINICAL RELEVANCE

This synbiotic mixture has no detectable effect on plasma levels of the analysed atopic disease markers, ex vivo cytokine production and circulating regulatory T cell percentage in infants with atopic dermatitis, besides down-regulation of IL-12 production in egg- and peanut-stimulated PBMCs. These results do not support the use of this synbiotic in clinical practice.

Synbiotics prevent asthma-like symptoms in infants with atopic dermatitis

BACKGROUND

  Infants with atopic dermatitis (AD) have a high risk of developing asthma. We investigated the effect of early intervention with synbiotics, a combination of probiotics and prebiotics, on the prevalence of asthma-like symptoms in infants with AD.

METHODS

  In a double-blind, placebo-controlled multicentre trial, ninety infants with AD, age <7\ months, were randomized to receive an extensively hydrolyzed formula with Bifidobacterium breve M-16V and a galacto/fructooligosaccharide mixture (Immunofortis(®) ), or the same formula without synbiotics during 12 weeks. After 1 year, the prevalence of respiratory symptoms and asthma medication use was evaluated, using a validated questionnaire. Also, total serum IgE and specific IgE against aeroallergens were determined.

FINDINGS

  Seventy-five children (70.7% male, mean age 17.3 months) completed the 1-year follow-up evaluation. The prevalence of 'frequent wheezing' and 'wheezing and/or noisy breathing apart from colds' was significantly lower in the synbiotic than in the placebo group (13.9%vs 34.2%, absolute risk reduction (ARR) -20.3%, 95% CI -39.2% to -1.5%, and 2.8%vs 30.8%, ARR -28.0%, 95% CI -43.3% to -12.5%, respectively). Significantly less children in the synbiotic than in the placebo group had started to use asthma medication after baseline (5.6%vs 25.6%, ARR -20.1%, 95% CI -35.7% to -4.5%). Total IgE levels did not differ between the two groups. No children in the synbiotic and five children (15.2%) in the placebo group developed elevated IgE levels against cat (ARR -15.2%, 95% CI -27.4% to -2.9%).

CONCLUSION

  These results suggest that this synbiotic mixture prevents asthma-like symptoms in infants with AD.

Oral treatment with probiotics reduces allergic symptoms in ovalbumin-sensitized mice: a bacterial strain comparative study

BACKGROUND/AIM

Evidence demonstrating an important role of the intestinal microbiota in the incidence of allergic disorders has led to the concept of using probiotics as possible antiallergic therapy. This study aimed to select a bacterial strain with the best antiallergic treatment effects from a panel of 6 bacterial strains in a mouse model of ovalbumin(OVA)-allergic asthma.

METHODS

OVA-sensitized BALB/c mice were orally administered the bacterial strains Bifidobacterium breve M-16V, B. infantis NumRes251, B. animalis NumRes252 and NumRes253, Lactobacillus plantarum NumRes8 and L. rhamnosus NumRes6. After challenge by OVA inhalation in the lungs, the response to methacholine was measured. Pulmonary inflammation was assessed by analyzing bronchoalveolar lavage fluid for the presence of eosinophils, neutrophils, macrophages and lymphocytes and for interleukin 4, interleukin 5, interleukin 10 and interferon-gamma. OVA-specific IgE, IgG1 and IgG2a were measured in serum. Next, the effect on acute allergic skin reaction was measured after treatment with B. breve M-16V and L. plantarum NumRes8.

RESULTS

Of the panel of 6 strains, B. breve M-16V and L. plantarum NumRes8 inhibited (1) the response to methacholine, (2) reduced the number of eosinophils in the bronchoalveolar lavage fluid, (3) reduced both OVA-specific IgE and (4) OVA-specific IgG1, whereas the other strains did not affect all these parameters simultaneously. B. breve M-16V but not L. plantarum NumRes8 reduced interleukin 4, interleukin 5 and interleukin 10. Furthermore, B. breve M-16V but not L. plantarum NumRes8 reduced acute allergic skin reactions to OVA.

CONCLUSION

B. breve M-16V was identified as the most potent antiallergic strain.

The evaluation of the immunomodulating properties of ERA-63 a pharmaceutical with estrogenic activity

This paper describes studies performed with ERA-63 a low molecular weight pharmaceutical with intended immunomodulatory effects. Since this compound was also known to have estrogenic activity a non-conventional approach was taken in order to differentiate between estrogenic and non-estrogenic-induced immunomodulatory effects. EE was included not only for qualitative comparison (hazard identification) between immunomodulatory effects but also, in case of similar effects, to facilitate the extrapolation of the findings in the rat to anticipated effects in humans. After 28 days of treatment with dosages ranging from pharmacological up to clearly toxic levels for both compounds the immunotoxic potential was assessed by performing a T cell-dependent antibody response and a host resistance assay in rats. Selected ERA-63 dose levels (0.167-0.2, 1.67-2 and 16.7-20mg/kg) were expected to have comparable estrogenic activity to respective EE dose levels (0.05, 0.5 and 5mg/kg). General toxicity parameters reflecting estrogenic activity (i.e. decreased body- and organ weights of thymus and testis, and increased bilirubin and GGT levels) confirmed the comparable estrogenic activity for both compounds at the dose levels tested. Together with the comparable estrogen-related immune suppression (i.e. decreases in specific antibody responses and an increased susceptibility for Listeria monocytogenes infects) for both compounds, this indicates that available clinical data for EE facilitates the human risk assessment of ERA-63.

Assessment of three human FcepsilonRI-transfected RBL cell-lines for identifying IgE induced degranulation utilizing peanut-allergic patient sera and peanut protein extract

Specific IgE sera screening studies are employed to investigate protein cross-reactivity. Such nonfunctional immunochemical methods cannot measure the biological activity of proteins. Therefore, an assay using RBL cells transfected with human FcepsilonRI was developed. Our objective was to evaluate the degranulation of three cell-lines expressing either the alpha-(RBL-hEI(a)-2B12 and RBL-30/25cells) or alpha-, beta-, and gamma-subunits (RBL SX-38) of the human FcepsilonRI by beta-hexosaminidase release. Purified human IgE and serum-derived polyclonal IgE from peanut-allergic subjects following challenge with anti-IgE or peanut protein extract, respectively, were utilized. Robust degranulation was induced in all three: RBL-30/25 (84%), -hEI(a)-2B12 (54%), SX-38 (94%), respectively, using purified IgE+anti-human IgE. Good release (18%, 40-45%, and 65%, respectively) occurred for one peanut-allergic subject+peanut extract with all cell-lines. With serum from three other peanut-allergic subjects, no beta-hexosaminidase release occurred with RBL-hEI(a)-2B12 cells+peanut extract, while only serum from one subject induced good degranulation, 30% and 60%, respectively, with RBL-30/25 and RBL SX 38 cells. Consistent degranulation with a potent food allergen (peanuts) was not observed. The assay's utility in safety assessment, predictive value and reproducibility for evaluating the cross-reactivity of proteins with allergens needs further investigation with additional proteins and well-characterized sera.

CD4+CD25+T cells regulate the intensity of hypersensitivity responses to peanut, but are not decisive in the induction of oral sensitization

BACKGROUND

Naturally occurring CD4+CD25+ regulatory T cells (Tregs) play a critical role in the maintenance of self-tolerance and it has been suggested that these Tregs may also be involved in preventing allergic disease.

OBJECTIVE

The precise role of CD4+CD25+ T cells in the regulation of allergic responses to mucosal antigens remains to be elucidated. In the present study, it was investigated whether CD4+CD25+ T cells are involved in the induction of oral tolerance and whether they play a role in controlling hypersensitivity responses to food proteins.

METHODS

CD4+CD25+ T cells were depleted with PC61 mAb before the induction of low dose oral tolerance to peanut extract (PE). In addition, CD4+CD25+ T cell depletion was performed during sensitization or before oral challenge, using a C3H/HeOuJ mouse model of allergic sensitization to peanut.

RESULTS

Oral tolerance to PE could not be induced in CD4+CD25+ T cell-depleted mice. However, CD4+CD25+ T cell depletion during long-term exposure to PE alone did not result in allergic sensitization. In sensitized mice, anti-CD25 treatment during oral exposure resulted in higher levels of PE-specific IgE and increased mast cell degranulation upon an oral challenge. In contrast, anti-CD25 treatment of PE-sensitized mice before oral challenges did not affect the level of mast cell degranulation.

CONCLUSION

These results indicate that CD4+CD25+ Tregs are involved in maintaining tolerance to oral antigens and regulate the intensity of an IgE-mediated food hypersensitivity response, but are not crucial in preventing sensitization. Accordingly, CD4+CD25+ Tregs may represent a potential tool for the treatment of food allergic disorders.

The effect of the food matrix on in vivo immune responses to purified peanut allergens

There is little knowledge about the factors that determine the allergenicity of food proteins. One aspect that remains to be elucidated is the effect of the food matrix on immune responses to food proteins. To study the intrinsic immunogenicity of allergens and the influence of the food matrix, purified peanut allergens (Ara h 1, Ara h 2, Ara h 3, or Ara h 6) and a whole peanut extract (PE) were tested in the popliteal lymph node assay (PLNA) and in an oral model of peanut hypersensitivity. In the PLNA, peanut proteins were injected into the hind footpad of BALB/c mice; in the oral exposure experiments C3H/HeOuJ mice were gavaged weekly with PE or allergens in the presence of cholera toxin (CT). Upon footpad injection, none of the allergens induced significant immune activation. In contrast, PE induced an increase in cell number, cytokine production, and activation of antigen-presenting cells. Furthermore, the presence of a food matrix enhanced the immune response to the individual allergens. Oral exposure to the purified allergens in the presence of CT induced specific IgE responses, irrespective of the presence of a food matrix. These results suggest that purified peanut allergens possess little intrinsic immune-stimulating capacity in contrast to a whole PE. Moreover, the data indicate that the food matrix can influence responses to individual proteins and, therefore, the food matrix must be taken into account when developing models for allergenic potential assessment.

Mixed antibody and T cell responses to peanut and the peanut allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6 in an oral sensitization model

BACKGROUND

Peanut allergy is known for its severity and persistence through life. Several peanut proteins have been identified as allergenic and are indicated as Ara h 1-7. Very little is known about the mechanisms that underlie sensitization to peanut proteins.

OBJECTIVE

The purpose of the present study was to reveal the immune responses that are induced against peanut and the peanut allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6 during sensitization, including the very early responses.

METHODS

Humoral and T cell responses against peanut and the peanut allergens were examined in an early and later stage of sensitization in an established murine model of peanut anaphylaxis. Therefore C3H/HeJ mice were orally exposed to two different doses of peanut extract plus cholera toxin.

RESULTS

Oral sensitization to peanut was characterized by an antigen-induced mixed cytokine response in the spleen (IL-4, IL-5, IL-10 and IFN-gamma), which could already be observed 7 days after the onset of exposure. Additionally, polyisotypic humoral responses (IgE, IgG1 and IgG2a) against peanut were found in the serum. Moreover, we demonstrated that these T helper (Th)1/Th2 cytokine and antibody responses were also directed specifically against the major peanut allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6.

CONCLUSIONS

This study implicates that both Th1 and Th2 phenomena are involved in the development of peanut allergy in the C3H/HeJ murine model. Furthermore, we show that the present oral model is suitable to examine immune responses to food allergens during different stages of sensitization upon treatment with a whole food extract.

Is Candida albicans a trigger in the onset of coeliac disease?

Coeliac disease is a T-cell-mediated autoimmune disease of the small intestine that is induced by ingestion of gluten proteins from wheat, barley, or rye. We postulate that Candida albicans is a trigger in the onset of coeliac disease. The virulence factor of C albicans-hyphal wall protein 1 (HWP1)-contains aminoacid sequences that are identical or highly homologous to known coeliac disease-related alpha-gliadin and gamma-gliadin T-cell epitopes. HWP1 is a transglutaminase substrate, and is used by C albicans to adhere to the intestinal epithelium. Furthermore, tissue transglutaminase and endomysium components could become covalently linked to the yeast. Subsequently, C albicans might function as an adjuvant that stimulates antibody formation against HWP1 and gluten, and formation of autoreactive antibodies against tissue transglutaminase and endomysium.