Immunomodulating properties of protein hydrolysates for application in cow's milk allergy

Current Practice in Pediatric Cow's Milk Protein Allergy-Immunological Features and Beyond

Cow's milk protein allergy is one of the most common pediatric food allergies. It poses a significant socioeconomic burden in industrialized countries and has a profound effect on the quality of life of affected individuals and their families. Diverse immunologic pathways can lead to the clinical symptoms of cow's milk protein allergy; some of the pathomechanisms are known in detail, but others need further elucidation. A comprehensive understanding of the development of food allergies and the features of oral tolerance could have the potential to unlock more precise diagnostic tools and novel therapeutic approaches for patients with cow's milk protein allergy.

Children with Delayed-Type Cow's Milk Protein Allergy May Be at a Significant Risk of Developing Immediate Allergic Reactions Upon Re-introduction

Background

Cow's Milk Protein Allergy (CMPA) is the most common food allergy in children. The reaction is classified into IgE-mediated immediate reaction and delayed-onset, according to the underlying immune mechanism, and hence, the timing of the symptoms. Case reports suggest that children, with delayed CMPA reactions on elimination diet, may develop severe immediate reactions on reintroduction.

Aim

The objective of this study was to evaluate the incidence and the risk factors of developing immediate reactions to milk and dairy products in children with CMPA whose initial presentations were of delayed type.

Methods

A retrospective chart review of children, aged 0-12 years, presented with delayed type CMPA reactions to the allergy-clinical immunology clinics, was performed. The diagnosis was made clinically, and with appropriate allergy tests when indicated.

Results

Sixty children were included. Males:female ratio was 1.7:1. Family history of atopy was in 72%, and 57% had personal history of atopy. Sixty percent were not breast fed. The most common concomitant food allergy was egg. The most common initial presentation was diarrhea without protein loss or bleeding followed by exacerbation of atopic dermatitis upon exposure to dairy products. Immediate reactions developed in 21.6% upon re-exposure. There were significant associations with concomitant food allergy (OR 56.6 (3.15-1016.1) P<0.0001), especially eggs (OR 12.85 (3.09-53.5) P<0.01).

Conclusion

Children with CMPA, who present with delayed-type allergic reactions, may be at a significant risk of developing immediate reactions upon reintroduction. Evaluation of possible IgE-mediated allergic reactions before reintroduction may be advisable.

Extensively Hydrolyzed Hypoallergenic Infant Formula with Retained T Cell Reactivity

BACKGROUND

Immunoglobulin E (IgE)-mediated cow's milk allergy (CMA) can be life-threatening and affects up to 3% of children. Hypoallergenic infant formulas based on hydrolyzed cow's milk protein are increasingly considered for therapy and prevention of cow's milk allergy. The aim of this study was to investigate the allergenic activity and ability to induce T cell and cytokine responses of an infant formula based on extensively hydrolyzed cow's milk protein (whey) (eHF, extensively hydrolyzed formula) supplemented with Galactooligosaccharides (GOS) and Limosilactobacillus fermentum CECT5716 (LF) to determine its suitability for treatment and prevention of CMA.

METHODS

eHF and standard protein formula based on intact cow's milk proteins (iPF) with or without Galactooligosaccharide (GOS) and Limosilactobacillus fermentum CECT5716 (LF) were investigated with allergen-specific antibodies and tested for IgE reactivity and allergenic activity in basophil degranulation assays with sera from cow's milk (CM)-allergic infants/children. Their ability to stimulate T cell proliferation and cytokine secretion in cultured peripheral blood mononuclear cells (PBMC) from CM-allergic infants and children was studied with a FACS-based carboxyfluorescein diacetate succinimidyl ester (CFSE) dilution assay and xMAP Luminex fluorescent bead-based technology, respectively.

RESULTS

An eHF supplemented with GOS and LF exhibiting almost no IgE reactivity and allergenic activity was identified. This eHF induced significantly lower inflammatory cytokine secretion as compared to an intact protein-based infant formula but retained T cell reactivity.

CONCLUSIONS

Due to strongly reduced allergenic activity and induction of inflammatory cytokine secretion but retained T cell reactivity, the identified eHF may be used for treatment and prevention of CMA by induction of specific T cell tolerance.

Development of the digestive system in early infancy and nutritional management of digestive problems in breastfed and formula-fed infants

Food digestion and absorption in infants are closely related to early growth and long-term health. Human milk and infant formula are the main food sources for 0-6 month-old infants. Due...

Preventive Administration of Non-Allergenic Bet v 1 Peptides Reduces Allergic Sensitization to Major Birch Pollen Allergen, Bet v 1

IgE-mediated allergy to birch pollen affects more than 100 million patients world-wide. Bet v 1, a 17 kDa protein is the major allergen in birch pollen responsible for allergic rhinoconjunctivitis and asthma in birch pollen allergic patients. Allergen-specific immunotherapy (AIT) based on therapeutic administration of Bet v 1-containing vaccines is an effective treatment for birch pollen allergy but no allergen-specific forms of prevention are available. We developed a mouse model for IgE sensitization to Bet v 1 based on subcutaneous injection of aluminum-hydroxide adsorbed recombinant Bet v 1 and performed a detailed characterization of the specificities of the IgE, IgG and CD4⁺ T cell responses in sensitized mice using seven synthetic peptides of 31-42 amino acids length which comprised the Bet v 1 sequence and the epitopes recognized by human CD4⁺ T cells. We then demonstrate that preventive systemic administration of a mix of synthetic non-allergenic Bet v 1 peptides to 3-4 week old mice significantly reduced allergic immune responses, including IgE, IgG, IgE-mediated basophil activation, CD4⁺ T cell and IL-4 responses to the complete Bet v 1 allergen but not to the unrelated major grass pollen allergen Phl p 5, without inducing Bet v 1-specific allergic sensitization or adaptive immunity. Our results thus demonstrate that early preventive administration of non-allergenic synthetic T cell epitope-containing allergen peptides could be a safe strategy for the prevention of allergen-specific IgE sensitization.

Hydrolysed Formulas in the Management of Cow's Milk Allergy: New Insights, Pitfalls and Tips

An allergy to cow's milk requires the avoidance of cow's milk proteins and, in some infants, the use of a hypoallergenic formula. This review aims to summarize the current evidence concerning different types of hydrolysed formulas (HF), and recommendations for the treatment of IgE- and non-IgE-mediated cow's milk allergy and functional gastrointestinal disorders in infancy, for which some dietary intervention and HF may be of benefit to both immune and motor mechanisms. Current guidelines recommend cow's milk protein (i.e., whey or casein) extensively hydrolysed formula (eHF) as the first choice for cow's milk allergy treatment, and amino acid formulas for more severe cases or those with reactions to eHF. Rice hydrolysed formulas (rHF) have also become available in recent years. Both eHF and rHF are well tolerated by the majority of children allergic to cow's milk, with no concerns regarding body growth or adverse effects. Some hydrolysates may have a pro-active effect in modulating the immune system due to the presence of small peptides and additional components, like biotics. Despite encouraging results on tolerance acquisition, evidence is still not conclusive, thus hampering our ability to draw firm conclusions. In clinical practice, the choice of hypoallergenic formula should be based on the infant's age, the severity, frequency and persistence of symptoms, immune phenotype, growth pattern, formula cost, and in vivo proof of tolerance and efficacy.

Fab Fragment of Immunoglobulin Y Modulates NF-κB and MAPK Signaling through TLR4 and αVβ3 Integrin and Inhibits the Inflammatory Effect on R264.7 Macrophages

High-purity Fab fragment and immunoglobulin Y (IgY) were prepared to evaluate their anti-inflammatory activity in the lipopolysaccharide (LPS)-induced Raw 264.7 macrophage system. Compared with IgY, the Fab fragment possessed a greater potency in inhibiting the inflammation by nitric oxide (NO)/inducible nitric oxide synthase (iNOS) and prostaglandin-E2 (PGE2)/cyclooxygenase-2 (COX-2) pathways. The Fab fragment attenuated the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) to 38.07 ± 1.86-48.39 ± 11.33 pg/mL (63.1-71.0% inhibition), 31.59 ± 3.91-38.08 ± 4.44 pg/mL (72.4-77.1% inhibition), and 20.62 ± 0.46-21.91 ± 0.65 pg/mL (50-53% inhibition), respectively. Additionally, the Fab fragment significantly inhibited the translocation of nuclear transcription factor-κB (NF-κB) p65 and the phosphorylation of mitogen-activated protein kinase (MAPK) proteins, including ERK1/2 (41.5/33.2%), JNK1/2 (44.2/39.6%), and p38 (42.2%). The Fab fragment could be internalized into cells, and the pretreatment of RAW 264.7 macrophages with the Fab fragment reduced the mRNA expression of the Toll-like receptor (TLR4, 32.7-44.4% inhibition) and αVβ3 integrin (76.1% inhibition). In conclusion, Fab fragments regulated the TLR4 and αVβ3 integrin-mediated inflammatory processes by blocking the NF-κB and MAPKs pathways in the LPS-induced RAW 264.7 macrophage system.

Tolerogenic Effect Elicited by Protein Fraction Derived From Different Formulas for Dietary Treatment of Cow's Milk Allergy in Human Cells

Several formulas are available for the dietary treatment of cow’s milk allergy (CMA). Clinical data suggest potentially different effect on immune tolerance elicited by these formulas. We aimed to comparatively evaluate the tolerogenic effect elicited by the protein fraction of different formulas available for the dietary treatment of CMA. Five formulas were compared: extensively hydrolyzed whey formula (EHWF), extensively hydrolyzed casein formula (EHCF), hydrolyzed rice formula (HRF), soy formula (SF), and amino acid-based formula (AAF). The formulas were reconstituted in water according to the manufacturer’s instructions and subjected to an in vitro infant gut simulated digestion using a sequential gastric and duodenal static model. Protein fraction was then purified and used for the experiments on non-immune and immune components of tolerance network in human enterocytes and in peripheral mononuclear blood cells (PBMCs). We assessed epithelial layer permeability and tight junction proteins (occludin and zonula occludens-1, ZO-1), mucin 5AC, IL-33, and thymic stromal lymphopoietin (TSLP) in human enterocytes. In addition, Th1/Th2 cytokine response and Tregs activation were investigated in PBMCs from IgE-mediated CMA infants. EHCF-derived protein fraction positively modulated the expression of gut barrier components (mucin 5AC, occludin and ZO-1) in human enterocytes, while SF was able to stimulate the expression of occludin only. EHWF and HRF protein fractions elicited a significant increase in TSLP production, while IL-33 release was significantly increased by HRF and SF protein fractions in human enterocytes. Only EHCF-derived protein fraction elicited an increase of the tolerogenic cytokines production (IL-10, IFN-γ) and of activated CD4+FoxP3+ Treg number, through NFAT, AP1, and Nf-Kb1 pathway. The effect paralleled with an up-regulation of FoxP3 demethylation rate. Protein fraction from all the study formulas was unable to induce Th2 cytokines production. The results suggest a different regulatory action on tolerogenic mechanisms elicited by protein fraction from different formulas commonly used for CMA management. EHCF-derived protein fraction was able to elicit tolerogenic effect through at least in part an epigenetic modulation of FoxP3 gene. These results could explain the different clinical effects observed on immune tolerance acquisition in CMA patients and on allergy prevention in children at risk for atopy observed using EHCF.

Stool microbiome, pH and short/branched chain fatty acids in infants receiving extensively hydrolyzed formula, amino acid formula, or human milk through two months of age

BACKGROUND

Early infant feeding with intact or extensively hydrolyzed (EH) proteins or free amino acids (AA) may differentially affect intestinal microbiota composition and immune reactivity. This multicenter, double-blind, controlled, parallel-group, pilot study compared stool microbiota from Baseline (1-7 days of age) up to 60 days of age in healthy term infants who received mother's own milk (assigned to human milk [HM] reference group) (n = 25) or were randomized to receive one of two infant formulas: AA-based (AAF; n = 25) or EH cow's milk protein (EHF; n = 28). Stool samples were collected (Baseline, Day 30, Day 60) and 16S rRNA genes were sequenced. Alpha (Shannon, Simpson, Chao1) and beta diversity (Bray Curtis) were analyzed. Relative taxonomic enrichment and fold changes were analyzed (Wilcoxon, DESEq2). Short/branched chain fatty acids (S/BCFA) were quantified by gas chromatography. Mean S/BCFA and pH were analyzed (repeated measures ANOVA).

RESULTS

At baseline, alpha diversity measures were similar among all groups; however, both study formula groups were significantly higher versus the HM group by Day 60. Significant group differences in beta diversity at Day 60 were also detected, and study formula groups were compositionally more similar compared to HM. The relative abundance of Bifidobacterium increased over time and was significantly enriched at Day 60 in the HM group. In contrast, a significant increase in members of Firmicutes for study formula groups were detected at Day 60 along with butyrate-producing species in the EHF group. Stool pH was significantly higher in the AAF group at Days 30 and 60. Butyrate increased significantly from Baseline to Day 60 in the EHF group and was significantly higher in study formula groups vs HM at Day 60. Propionate was also significantly higher for EHF and AAF at Day 30 and AAF at Day 60 vs HM. Total and individual BCFA were higher for AAF and EHF groups vs HM through Day 60.

CONCLUSIONS

Distinct patterns of early neonatal microbiome, pH, and microbial metabolites were demonstrated for infants receiving mother's own milk compared to AA-based or extensively hydrolyzed protein formula. Providing different sources of dietary protein early in life may influence gut microbiota and metabolites.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02500563 . Registered July 28, 2015.

Antioxidant and anti-inflammatory peptide fraction from oyster soft tissue by enzymatic hydrolysis

Recent studies have confirmed that the peptide fractions derived from marine organisms exhibit good antioxidant and anti-inflammatory activity, and oyster is an excellent nutrient resource with high-protein content. In this study, the peptide fractions from oyster soft tissue were prepared after hydrolysis by pepsin (pH 2, 37°C), trypsin (pH 8, 37°C), and Maxipro PSP (pH 4.2, 50°C) with the optimized parameters (enzyme-to-substrate (E/S) ratio, 1:100 (w/w); hydrolysis time, 4 hr), respectively. Four fractions named as PEP-1, PEP-2, TRYP-2, and MIX-2 were obtained after separation with elution consisting of 20% or 40% ethanol. The MIX-2 exhibited the highest hydrophobicity correlated well with its hydrophobic amino acid content, and TRYP-2 exhibited much better antioxidant activity than other three elution samples. Furthermore, all of the bioactive peptide fractions were noncytotoxic and could selectively repress pro-inflammatory mediators, TNF-α, IL-1β, IL-6, and i-NOS, at transcription level in RAW264.7 macrophage cells after LPS stimulation. The result suggests that the peptide fraction TRYP-2 from oyster soft tissue hydrolysates might be a potential resource for natural anti-inflammatory components.

Dietary Prevention of Atopic March in Pediatric Subjects With Cow's Milk Allergy

Cow's milk allergy (CMA) is one of the most prevalent food allergies and the most expensive allergic diseases in the pediatric age. There is no cure for CMA, and actual disease management is based on strict avoidance of cow milk protein-containing foods, access to rescue medication, and use of substitutive formulas. Early-life CMA could be one of the first steps of the "allergic march" (AM), leading to the occurrence of other atopic manifestations later in the life, including asthma and oculorhinitis, with subsequent further increase of costs for health care systems and families of affected children. In the last years, diet is emerged as a relevant strategy to prevent allergic diseases through, at least in part, epigenetic modulation of immune system. We provide an overview of studies that investigate the potential role of different dietary strategies in preventing the AM in pediatric patients with CMA.

Molecular Approaches for Diagnosis, Therapy and Prevention of Cow´s Milk Allergy

Cow´s milk is one of the most important and basic nutrients introduced early in life in our diet but can induce IgE-associated allergy. IgE-associated allergy to cow´s milk can cause severe allergic manifestations in the gut, skin and even in the respiratory tract and may lead to life-threatening anaphylactic shock due to the stability of certain cow´s milk allergens. Here, we provide an overview about the allergen molecules in cow´s milk and the advantages of the molecular diagnosis of IgE sensitization to cow´s milk by serology. In addition, we review current strategies for prevention and treatment of cow´s milk allergy and discuss how they could be improved in the future by innovative molecular approaches that are based on defined recombinant allergens, recombinant hypoallergenic allergen derivatives and synthetic peptides.

Cow's Milk Allergy: Immunomodulation by Dietary Intervention

Cow’s milk proteins cause allergic symptoms in 2% to 3% of all infants. In these individuals, the physiological mechanism of tolerance is broken with subsequent possible sensitization to antigens, which can lead eventually to allergic responses. The present review aims to provide an overview of different aspects of immune modulation by dietary intervention in cow’s milk allergy (CMA). It focuses on pathogenetic mechanisms of different CMA related disorders, e.g., gastroesophageal reflux and eosinophilic esophagitis, highlighting the role of dietary management on innate and adaptive immune systems. The traditional dietary management of CMA has greatly changed in the last years, moving from a passive approach, consisting of an elimination diet to relieve symptoms, to a “proactive” one, meaning the possibility to actively modulate the immune system. Thus, new insights into the role of hydrolysates and baked milk in immunomodulation are addressed here. Additionally, nutritional components, such as pre- and probiotics, may target the immune system via microbiota, offering a possible road map for new CMA prevention and treatment strategies.

Antimicrobial and Immunomodulatory Properties and Applications of Marine-Derived Proteins and Peptides

Marine organisms provide an abundant source of potential medicines. Many of the marine-derived biomaterials have been shown to act as different mechanisms in immune responses, and in each case they can significantly control the immune system to produce effective reactions. Marine-derived proteins, peptides, and protein hydrolysates exhibit various physiologic functions, such as antimicrobial, anticancer, antioxidant, antihypertensive, and anti-inflammatory activities. Recently, the immunomodulatory properties of several antimicrobial peptides have been demonstrated. Some of these peptides directly kill bacteria and exhibit a variety of immunomodulatory activities that improve the host innate immune response and effectively eliminate infection. The properties of immunomodulatory proteins and peptides correlate with their amino acid composition, sequence, and length. Proteins and peptides with immunomodulatory properties have been tested in vitro and in vivo, and some of them have undergone different clinical and preclinical trials. This review provides a comprehensive overview of marine immunomodulatory proteins, peptides, and protein hydrolysates as well as their production, mechanisms of action, and applications in human therapy.

Identification of a TLR2 Inhibiting Wheat Hydrolysate

SCOPE

Wheat hydrolysates are used in medical nutrition to provide undernourished patients a readily digestible protein source, for instance to recover from chemotherapy-induced intestinal mucosal inflammation. Since many hydrolysates of different sources can modulate the immune system, likely via Toll-like receptors (TLRs), it is hypothesized that also wheat hydrolysates might interact with TLR signaling, which could be a way to prevent intestinal inflammation and damage.

METHODS AND RESULTS

The capacity of three wheat hydrolysates to modulate immunity by interfering with TLR signaling is determined. All wheat hydrolysates have TLR modulating effects but only one has strong TLR2 inhibiting effects, attenuating both TLR2/1 and TLR2/6 signaling in a reporter cell system. This is likely induced by direct TLR2-ectodomain binding, as confirmed by ELISA. Furthermore, this TLR2 blocking hydrolysate reduces IL-6 production in human dendritic cells. Application of reversed-phase-ultra HPLC combined with MS reveals that the presence of peptide WQIPEQSR is associated with the observed TLR2 inhibiting capacity.

CONCLUSION

The study demonstrates TLR2-inhibiting capacities of a wheat hydrolysate. The findings provide a good start for further research to investigate whether this hydrolysate might contribute to the management of intestinal mucosal inflammation in cancer patients receiving chemotherapy.

Intravenous vitamin C in the treatment of allergies: an interim subgroup analysis of a long-term observational study

Objective Oxidative stress appears to be a key factor in the pathogenesis of allergic diseases and a potential therapeutic target in allergy treatment. Allergic diseases are reportedly associated with reduced plasma levels of ascorbate, which is a key physiological antioxidant. Ascorbate prevents excessive inflammation without reducing the defensive capacity of the immune system. Methods An interim analysis of a multicenter, prospective, observational study was conducted to investigate the change in disease-specific and nonspecific symptoms (fatigue, sleep disorders, depression, and lack of mental concentration) during adjuvant treatment with intravenous vitamin C (Pascorbin®; Pascoe, Giessen, Germany) in 71 patients with allergy-related respiratory or cutaneous indications. Results Between the start and end of treatment, the mean sum score of three disease-specific symptoms decreased significantly by 4.71 points and that of four nonspecific symptoms decreased significantly by 4.84 points. More than 50% of patients took no other allergy-related medication besides vitamin C. Conclusions Our observations suggest that treatment with intravenous high-dose vitamin C reduces allergy-related symptoms. Our observations form a basis for planning a randomized controlled clinical trial to obtain more definitive evidence of the clinical relevance of our findings. We also obtained evidence of ascorbate deficiency in allergy-related diseases.

TRIAL REGISTRATION

Clinical Trials NCT02422901.

The epithelial barrier-protecting properties of a soy hydrolysate

Enhancing the epithelial barrier function could be a possible strategy to prevent food allergy or reduce its symptoms. Soy hydrolysates containing bioactive peptides could be instrumental in this. In this study, the protective effects of pretreatment with 6 soy hydrolysates on calcium ionophore A23187-induced TEER reduction were studied in T84 cells. The effects of the most potent soy hydrolysate on tight junction gene expression were studied. In order to identify the underlying pathways involved, the barrier disruptor specificity of the effect was studied by comparing the protective effects on TEER and Lucifer Yellow flux after the exposure to barrier disruptors that work via different intracellular pathways, i.e. the disruptors A23187, mellitin, and deoxynivalenol (DON). Preincubation with one of the six hydrolysates protected the epithelial cells from a decrease in TEER induced by A23187 (restored to 105% of the starting point, while A23187 alone decreased to 53% of the starting value) and mellitin (restored to 11% of the starting point, while mellitin alone decreased to 3.8% of the starting value). This soy hydrolysate was found to increase claudin-1 and decrease claudin-2 expression. The protective effect of the hydrolysate on TEER was specific for the barrier disruptors A23187 and mellitin, but was not observed for DON. This observation suggests that the soy hydrolysate may act via PKC isoforms, which are known to lead to changes in the expression of claudin-1 and 2. Our data suggest that specific soy hydrolysates may be designed to strengthen the epithelial barrier which might be instrumental in the management of the barrier function in individuals at risk of developing food allergy.

Immunomodulatory Protein Hydrolysates and Their Application

Immunomodulatory protein hydrolysate consumption may delay or prevent western immune-related diseases. In order to purposively develop protein hydrolysates with an optimal and reproducible immunomodulatory effect, knowledge is needed on which components in protein hydrolysates are responsible for the immune effects. Important advances have been made on this aspect. Also, knowledge on mechanisms underlying the immune modulating effects is indispensable. In this review, we discuss the most promising application possibilities for immunomodulatory protein hydrolysates. In order to do so, an overview is provided on reported in vivo immune effects of protein hydrolysates in both local intestinal and systemic organs, and the current insights in the underlying mechanisms of these effects. Furthermore, we discuss current knowledge and physicochemical approaches to identify the immune active protein sequence(s). We conclude that multiple hydrolysate compositions show specific immune effects. This knowledge can improve the efficacy of existing hydrolysate-containing products such as sports nutrition, clinical nutrition, and infant formula. We also provide arguments for why immunomodulatory protein hydrolysates could be applied to manage the immune response in the increasing number of individuals with a higher risk of immune dysfunction due to, for example, increasing age or stress.

Immunomodulating protein aggregates in soy and whey hydrolysates and their resistance to digestion in an in vitro infant gastrointestinal model: new insights in the mechanism of immunomodulatory hydrolysates

Hydrolysates, which are used in hypoallergenic infant formulas, have been found to possess immune modulating effects. For an optimal utilization of hydrolysates, the working mechanisms and responsible proteins underlying the effects should be elucidated. In this study, the immunomodulating activity of whey and soy hydrolysates was studied by quantifying TLR activation and assessing cytokine production in hydrolysate stimulated dendritic cells. The responsible protein fraction was identified and characterized by gel electrophoresis. The immune effects under gastrointestinal conditions were studied by digesting the hydrolysates in an in vitro infant digestion model, after which the digests were analyzed. In both soy and whey hydrolysates, TLR activation and cytokine production in dendritic cells were induced by a fraction containing protein aggregates larger than 1000 kDa, which were formed by electrostatic interactions and disulfide bonds. Only soy aggregates remained intact during duodenal digestion, and maintained the TLR activating capacity. Soy and whey protein aggregates larger than 1000 kDa possess immunomodulatory properties, but only soy aggregates remain under intestinal digestion conditions. This knowledge is important for a better understanding of the effects of hydrolysates.

Immunomodulating peptides for food allergy prevention and treatment

Among the most promising strategies currently assayed against IgE-mediated allergic diseases stands the possibility of using immunomodulating peptides to induce oral tolerance toward offending food allergens or even to prevent allergic sensitization. This review focuses on the beneficial effects of food derived immunomodulating peptides on food allergy, which can be directly exerted in the intestinal tract or once being absorbed through the intestinal epithelial barrier to interact with immune cells. Food peptides influence intestinal homeostasis by maintaining and reinforcing barrier function or affecting intestinal cell-signalling to nearby immune cells and mucus secretion. In addition, they can stimulate cells of the innate and adaptive immune system while supressing inflammatory responses. Peptides represent an attractive alternative to whole allergens to enhance the safety and efficacy of immunotherapy treatments. The conclusions drawn from curative and preventive experiments in murine models are promising, although there is a need for more pre-clinical studies to further explore the immunomodulating strategy and its mechanisms and for a deeper knowledge of the peptide sequence and structural requirements that determine the immunoregulatory function.

Prevention and Management of Cow's Milk Allergy in Non-Exclusively Breastfed Infants

Introduction: The prevention and management of cow milk allergy (CMA) is still debated. Since CMA is much less frequent in breastfed infants, breastfeeding should be stimulated. Method: Literature was searched using databases to find original papers and reviews on this topic. Results: Hydrolysates with a clinical proof of efficacy are recommended in the prevention and treatment of CMA. However, not all meta-analyses conclude that hydrolysates do prevent CMA or other atopic manifestations such as atopic dermatitis. There are pros and cons to consider partially hydrolysed protein as an option for starter infant formula for each non-exclusively breastfed infant. A challenge test is still recommended as the most specific and sensitive diagnostic test, although a positive challenge test does not proof that the immune system is involved. The Cow Milk Symptom Score (CoMiSS™) is an awareness tool that enables healthcare professionals to better recognize symptoms related to the ingestion of cow milk, but it still needs validation as diagnostic tool. The current recommended elimination diet is a cow milk based extensive hydrolysate, although rice hydrolysates or soy infant formula can be considered in some cases. About 10 to 15% of infants allergic to cow milk will also react to soy. Mainly because of the higher cost, amino acid based formula is reserved for severe cases. There is no place for infant formula with intact protein from other animals as cross-over allergenicity is high. During recent years, attention focused also on the bifidogenic effect of prebiotics and more recently also on human milk oligosaccharides. A bifidogenic gastrointestinal microbiome may decrease the risk to develop allergic disease. The addition of probiotics and prebiotics to the elimination diet in treatment may enhance the development of tolerance development. Conclusion: Breastfeeding is the best way to feed infants. Cow milk based extensive hydrolysates remain the first option for the treatment of CMA for the majority of patients, while amino acid formulas are reserved for the most severe cases. Rice hydrolysates and soy infant formula are second choice options. Partial hydrolysates with clinical proof of efficacy are recommended in some guidelines in the prevention of CMA and allergic disease in at risk infants, and may be considered as an option as protein source in starter infant formula.

Anti-Inflammatory and Antioxidant Properties of Peptides Released from β-Lactoglobulin by High Hydrostatic Pressure-Assisted Enzymatic Hydrolysis

Background: β-lactoglobulin hydrolysates (BLGH) have shown antioxidant, antihypertensive, antimicrobial, and opioid activity. In the current study, an innovative combination of high hydrostatic pressure and enzymatic hydrolysis (HHP–EH) was used to increase the yield of short bioactive peptides, and evaluate the anti-inflammatory and antioxidant properties of the BLGH produced by the HHP–EH process. Method: BLG was enzymatically hydrolyzed by different proteases at an enzyme-to-substrate ratio of 1:100 under HHP (100 MPa) and compared with hydrolysates obtained under atmospheric pressure (AP-EH at 0.1 MPa). The degree of hydrolysis (DH), molecular weight distribution, and the antioxidant and anti-inflammatory properties of hydrolysates in chemical and cellular models were evaluated. Results: BLGH obtained under HHP–EH showed higher DH than the hydrolysates obtained under AP-EH. Free radical scavenging and the reducing capacity were also significantly stronger in HHP-BLGH compared to AP-BLGH. The BLGH produced by alcalase (Alc) (BLG-Alc) showed significantly higher antioxidant properties among the six enzymes examined in this study. The anti-inflammatory properties of BLG-HHP-Alc were observed in lipopolysaccharide-stimulated macrophage cells by a lower level of nitric oxide production and the suppression of the synthesis of pro-inflammatory cytokines. Peptide sequencing revealed that 38% of the amino acids in BLG-HHP-Alc are hydrophobic and aromatic residues, which contribute to its anti-inflammatory properties. Conclusions: Enzymatic hydrolysis of BLG under HHP produces a higher yield of short bioactive peptides with potential antioxidant and anti-inflammatory effects.

Extensively hydrolyzed casein formula alone or with L. rhamnosus GG reduces β-lactoglobulin sensitization in mice

BACKGROUND

Extensively hydrolyzed casein formula (EHCF) has been proposed for the prevention and is commonly used for the treatment of cow's milk allergy (CMA). The addition of the probiotic Lactobacillus rhamnosus GG (LGG) to EHCF may induce faster acquisition of tolerance to cow's milk. The mechanisms underlying this effect are largely unexplored. We investigated the effects of EHCF alone or in combination with LGG on β-lactoglobulin (BLG) sensitization in mice.

METHODS

Three-week-old C3H/HeOuJ mice were sensitized by oral administration of BLG using cholera toxin as adjuvant at weekly intervals for 5 weeks (sensitization period). Two experimental phases were conducted: (i) EHCF or EHCF+LGG given daily, starting 2 weeks before the sensitization period and then given daily for 5 weeks and (ii) EHCF or EHCF+LGG given daily for 4 weeks, starting 1 week after the sensitization period. Diet free of cow's milk protein was used as control. Acute allergic skin response, anaphylactic symptom score, body temperature, intestinal permeability, anti-BLG serum IgE, and interleukin (IL)-4, IL-5, IL-10, IL-13, IFN-γ mRNA expression were analyzed. Peptide fractions of EHCF were characterized by reversed-phase (RP)-HPLC, MALDI-TOF mass spectrometry, and nano-HPLC/ESI-MS/MS.

RESULTS

Extensively hydrolyzed casein formula administration before or after BLG-induced sensitization significantly reduced acute allergic skin reaction, anaphylactic symptom score, body temperature decrease, intestinal permeability increase, IL-4, IL-5, IL-13, and anti-BLG IgE production. EHCF increased expression of IFN-γ and IL-10. Many of these effects were significantly enhanced by LGG supplementation. The peptide panels were similar between the two study formulas and contained sequences that could have immunoregulatory activities.

CONCLUSIONS

The data support dietary intervention with EHCF for CMA prevention and treatment through a favorable immunomodulatory action. The observed effects are significantly enhanced by LGG supplementation.