Oral Immunotherapy Using Diet Supplemented with 0.1％ Egg White Ameliorates the Severity of Allergy to an Extent Comparable to Oral Gavage Therapy

Abstract

Summary : We examined whether oral immunotherapy （ OIT ） using a diet supplemented with 0 . 1％ egg white ameliorates the severity of allergy and immunological tolerance to an extent comparable to OIT by oral gavage. Allergy to egg white was induced in mice via peritoneal administration of egg white-mixed aluminum hydroxide gel, and the allergy reaction was induced via oral gavage of egg white. Mice sensitized with egg white were di-vided into three groups （ untreated group, oral gavage group, and diet group ） , and non-sensitized mice were also prepared. The OIT period lasted 4 weeks. The diet group was fed a 20％ casein diet containing 0 . 1％ egg white, and the other groups were fed a 20％ casein diet alone. Furthermore, the oral gavage group was forcibly administered 100 μ L of 30 mg/mL egg white solution orally every day, while each of the other groups received 100 μ L of phosphate-buffered saline by daily forced oral gavage. The change in rectal temperature following in-traperitoneal food challenge was inhibited to a greater degree in the oral gavage and diet groups than in the untreated group. Moreover, the ovalbumin-specific IgE concentrations and ovomucoid-specific IgE titers in plasma were lower in the oral gavage and diet groups than in the untreated group. However, these antibodies did not differ between the oral gavage and diet groups. These findings suggest that if the amount of allergen ingested per day is small and equivalent, continuous intake of the allergen has therapeutic efficacy similar to that of sin-gle oral administration of the allergen.