INHIBITION OF AIRWAY INFLAMMATION IN RDER-F-2-SENSITIZED MICE BY ORAL-ADMINISTRATION OF RECOMBINANT DER-F-2

Recombinant Der f 2 (rDer f 2) is a promising new allergen expected to improve the diagnosis and immunotherapy of house dust mite allergy an d to further immunological studies. To evaluate the hyposensitizing ac tivity of rDer f 2 to mite allergy, we examined the effect of its oral administration on allergic inflammation in A/J mice immunized with mi te allergens. A/J mice immunized with rDer f 2 alone or rDer f 2 + cru de mite extract were orally given 0 (control), 0.01, 0.1, or 1 mg/day of rDer f 2 for 4 weeks, followed by an antigen inhalation challenge. Twenty-four hours after rDer f 2 inhalation, control animals experienc ed severe leukocyte influx into the airway. The infiltrating cells wer e mainly neutrophils, with some eosinophils and lymphocytes, The conce ntrations of IL4, IFN gamma, and soluble ICAM-1 in the bronchial alveo lar lavage fluid increased twofold compared with values before rDer f 2 inhalation. In contrast, inflammation was significantly suppressed i n mice given 1 mg/day of rDer f 2 orally for 4 weeks and partially sup pressed in those fed 0.1 mg/day of the antigen, Plasma anti-rDer f 2 a ntibody levels were unchanged by oral rDer f 2 treatment. Mite extract inhalation challenge provoked neutophilia in rDer f 2 + mite-sensitiz ed control mice, and this allergic reaction tended to decrease in sens itized mice fed 1 mg/day of rDer f 2 orally for 4 weeks, We conclude t hat rDer f 2 has hyposensitizing activities and may be useful in immun otherapy for house dust mite allergy. (C) 1997 Academic Press.