Micronutritional supplementation with a holoBLG‐based FSMP (food for special medical purposes)‐lozenge alleviates allergic symptoms in BALB/c mice: Imitating the protective farm effect

Abstract Background Previously, the protective farm effect was imitated using the whey protein beta‐lactoglobulin (BLG) that is spiked with iron‐flavonoid complexes. Here, we formulated for clinical translation a lozenge as food for special medical purposes (FSMP) using catechin‐iron complexes as ligands for BLG. The lozenge was tested in vitro and in a therapeutical BALB/c mice model. Methods Binding of iron‐catechin into BLG was confirmed by spectroscopy and docking calculations. Serum IgE binding of children allergic or tolerating milk was assessed to loaded (holo‐) versus empty (apo‐) BLG and for human mast cell degranulation. BLG and Bet v 1 double‐sensitized mice were orally treated with the holoBLG or placebo lozenge, and immunologically analysed after systemic allergen challenge. Human PBMCs of pollen allergic subjects were flow cytometrically assessed after stimulation with apoBLG or holoBLG using catechin‐iron complexes as ligands. Results One major IgE and T cell epitope were masked by catechin‐iron complexes, which impaired IgE binding of milk‐allergic children and degranulation of mast cells. In mice, only supplementation with the holoBLG lozenge reduced clinical reactivity to BLG and Bet v 1, promoted Tregs, and suppressed antigen presentation. In allergic subjects, stimulation of PBMCs with holoBLG led to a significant increase of intracellular iron in circulating CD14+ cells with significantly lower expression of HLADR and CD86 compared to their stimulation with apoBLG. Conclusion The FSMP lozenge targeted antigen presenting cells and dampened immune activation in human immune cells and allergic mice in an antigen‐non‐specific manner, thereby conferring immune resilience against allergic symptoms.