The major whey protein β-lactoglobulin inhibits IgE-mediated degranulation of RBL-2H3 cells and passive cutaneous anaphylaxis in mice

Various foodstuffs were screened for the ability to prevent mast cell degranulation using a rat basophilic leukaemia cell line (RBL-2H3 cells); whey emerged as a candidate to alleviate allergic symptoms. Further exploration of the suppressive effect of whey on mast cell degranulation led to identification of β-lactoglobulin (BLG) as one of the active substances. The potential of BLG to modulate allergic responses of mast cells using the RBL-2H3 cells in vitro with the passive cutaneous anaphylaxis (PCA) reaction model mice in vivo is described. BLG was shown to suppress degranulation of RBL-2H3 cells. The molecular mechanism underlying the inhibitory effect of BLG on degranulation of RBL-2H3 cells included reduced phosphorylation of the tyrosine kinase Syk, phosphoinositide 3-kinase, and phospholipase C-γ1/2. Furthermore, oral administration of BLG tended to suppress the PCA reaction in the anti-dinitrophenol (DNP) IgE-sensitised, DNP-human serum albumin-challenged BALB/c mice, presenting a new biological functionality of BLG.