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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., Competing Interests: The Department of Translational Medical Science received research grants from Nestlè, Vevey, Switzerland; Kraft Heinz Chicago, Illinois, USA; Danone, Paris, France; Mead Johnson, Evansville, IN, USA; and Novalac, Paris, France. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Paparo, Picariello, Bruno, Pisapia, Canale, Sarracino, Nocerino, Carucci, Cosenza, Cozzolino and Berni Canani.)

Background: Hydrolyzed cow's milk protein formulas are widely used for infants with a history or risk of cow's milk allergy. Based on the current theory that food allergen sensitization occurs via the skin, we investigated the epicutaneous immunogenicity of partially hydrolyzed whey proteins, which are ingredients in infant formulas., Methods: BALB/c mice were exposed epicutaneously to whey protein concentrate (WPC) or partial whey protein hydrolysates (PWH1 or PWH2) on tape-stripped skin. Sensitization was assessed by evaluating serum β-lactoglobulin (β-LG)-specific antibodies, basophil activation, and cytokine production from β-LG-stimulated lymphoid cells. The anaphylaxis reaction was evaluated by measuring the rectal temperature and plasma level of mouse mast cell protease-1 after oral β-LG challenge. Immune cell accumulation in the skin was also analyzed., Results: Substantive sensitization and β-LG-induced anaphylaxis reaction were observed in WPC-exposed mice, whereas no significant changes were observed in PWH1- or PWH2-exposed mice. The basophil and eosinophil counts increased in WPC-exposed murine skin, not but in PWH1- or PWH2-exposed mice., Conclusion: The epicutaneous immunogenicity of PWH1 and PWH2 is markedly decreased, which may reduce the risk of allergen sensitization. Further studies are required to investigate the clinical value of these partial hydrolysates for high-risk infants., (© 2020 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

The aim of the study was to investigate the use of serine protease from Yarrowia lipolytica yeast for reduction of milk proteins allergenicity. Whey protein concentrate (WPC-80), αs-casein and their hydrolysates were analyzed for the capacity to bind IgE and IgG antibodies present in sera from patients with cow milk protein allergy using a competitive ELISA. The hydrolysis of αs-casein and whey protein concentrate contributed to a significant reduction of their immunoreactive epitopes. In case of IgE antibodies, the lowest binding capacity was detected in the 24 h hydrolysates of both proteins in which the inhibition of the reaction was ≤20 and ≤68% for αs-casein and whey protein concentrate respectively. One hour hydrolysis of WPC-80 reduced the protein antigenicity, while the longer time (5 h) might lead to the exposure of new IgE - reactive epitopes., (Copyright © 2019. Published by Elsevier Ltd.)

Background: We sought to determine whether an extensively hydrolyzed formula (EHF) supplemented with two human milk oligosaccharides (HMO) was tolerated by infants with cow's milk protein allergy (CMPA)., Methods: A whey-based EHF (Test formula) containing 2'fucosyl-lactose (2'FL) and lacto-N-neotetraose (LNnT) was assessed for clinical hypoallergenicity and safety. The Control formula was a currently marketed EHF without HMO. Children with CMPA, aged 2 months to 4 years, were assessed by double-blind, placebo-controlled food challenges (DBPCFC) to both formulas, in randomized order. If both DBPCFC were negative, subjects participated in a one-week, open food challenge (OFC) with the Test formula. Symptoms and adverse events were recorded. Hypoallergenicity was accepted if at least 90% (with 95% confidence intervals) of subjects tolerated the Test formula., Results: Of the 82 children with CMPA that were screened, 67 (intention-to-treat [ITT] cohort-mean age 24.5 ± 13.6 months; range 2-57; 45 [67.2%] male) were randomized to receive either the Test or the Control formula during the first DBPCFC. Of these, 64 children completed at least one DBPCFC (modified intention-to-treat [mITT] cohort). Three children were excluded due to protocol deviations (per protocol [PP] cohort; n = 61). There was one allergic reaction to the Test, and one to the Control formula. On the mITT analysis, 63 out of 64 (98.4%; 95% CI lower bound 92.8%), and on the PP analysis 60 out of 61 (98.4%; 95% CI lower bound 92.5%) participants tolerated the Test formula, confirming hypoallergenicity., Conclusion: The whey-based EHF supplemented with 2'FL and LNnT met the clinical hypoallergenicity criteria and can be recommended for the management of CMPA in infants and young children., Competing Interests: The authors declare the following potential conflicts of interest: A.N.-W. received research support from DBV Technologies, Astellas Pharma, Nutricia, Nestlé Health Science; Royalties from Up-To-Date; Advisory Board honoraria from Gerber Institute, Merck, ALK, Abello, and Sanofi Aventis. L.C. is an employee of Nestlé Nutrition, USA. B.C. is an employee of Clinipace. K.R. and R.G.H. are employees of Nestlé Health Science.

Background: Epicutaneous sensitization to food allergens can occur through defective skin barriers. However, the relationship between oral tolerance and epicutaneous sensitization remains to be elucidated. We aimed to determine whether prior oral exposure to whey proteins or their hydrolysates prevents epicutaneous sensitization and subsequent food-allergic reaction to the whey protein, β-lactoglobulin (β-LG), and investigated the underlying mechanisms., Methods: BALB/c mice were given whey protein concentrate (WPC), two kinds of partial whey protein hydrolysate (PWH1 or PWH2), or extensive whey protein hydrolysate (EWH) in drinking water for 21 days. The mice were then epicutaneously sensitized with β-LG on tape-stripped skin. Sensitization was assessed by basophil activation tests and by measuring the level of serum β-LG-specific antibodies and cytokines secreted from β-LG-restimulated spleen and mesenteric lymph node (MLN) cells. Development of an allergic reaction was assessed by monitoring body temperature and by measuring mast cell protease-1 level in plasma after the β-LG oral challenge. Activated T-cell population among β-LG-restimulated MLN cells was also analyzed., Results: In mice fed with WPC, PWH1, or PWH2, sensitization and the development of an allergic reaction were totally reduced. The acceleration of cytokine release from the spleen and MLN cells or T-cell activation was not evident after β-LG restimulation. In EWH-fed mice, a suppressive effect, though milder than that in WPC-, PWH1-, or PWH2-fed mice, was observed during the development of the allergic reaction., Conclusions: Prior oral exposure to partially hydrolyzed whey protein prevents epicutaneous sensitization and subsequent allergic response to β-LG in mice., (© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Food allergy is an adverse immune response to dietary proteins. Hydrolysates are frequently used for children with milk allergy. However, hydrolysates effects afterwards are poorly studied. The aim of this study was to investigate the immunological consequences of hydrolyzed whey protein in allergic mice. For that, we developed a novel model of food allergy in BALB/c mice sensitized with alum-adsorbed β-lactoglobulin. These mice were orally challenged with either whey protein or whey hydrolysate. Whey-challenged mice had elevated levels of specific IgE and lost weight. They also presented gut inflammation, enhanced levels of SIgA and IL-5 as well as decreased production of IL-4 and IL-10 in the intestinal mucosa. Conversely, mice challenged with hydrolyzate maintained normal levels of IgE, IL-4 and IL-5 and showed no sign of gut inflammation probably due to increased IL-12 production in the gut. Thus, consumption of hydrolysate prevented the development of clinical signs of food allergy in mice., (Copyright © 2015 Elsevier Inc. All rights reserved.)