Influence of the Adjuvants and Genetic Background on the Asthma Model Using Recombinant Der f 2 in Mice

Der f 2 is the group 2 major allergen of a house dust mite (Dermatophagoides farinae) and its function has been recently suggested. To determine the optimal condition of sensitization to recombinant Der f 2 (rDer f 2) in murine model of asthma, we compared the effectiveness with different adjuvants in BALB/c and C57BL/6 mice. Mice from both strains sensitized with rDer f 2 by intraperitoneal injection or subcutaneous injection on days 1 and 14. The dosage was 20 µg. Freund's adjuvants with pertussis toxin (FP) or alum alone were used as adjuvants. On days 28, 29, and 30, mice were challenged intranasally with 0.1% rDer f 2. We evaluated airway hyperresponsivenss, eosinophil proportion in lung lavage, airway inflammation, and serum allergen specific antibody responses. Naive mice were used as controls. Airway hyperresponsiveness was increased in C57BL/6 with FP, and BALB/c with alum (PC200: 13.5±6.3, 13.2±6.7 vs. >50 mg/ml, p<0.05). The eosinophil proportion was increased in all groups; C57BL/6 with FP, BALB/c with FP, C57BL/6 with alum, BALB/c with alum (24.8±3.6, 20.3±10.3, 11.0±6.9, 5.7±2.8, vs. 0.0±0.0%, p<0.05). The serum allergen specific IgE levels were increased in C57BL/6 with FP or alum (OD: 0.8±1.4, 1.1±0.8, vs. 0.0±0.0). C57BL/6 mice were better responders to rDer f 2 and as for adjuvants, Freund's adjuvant with pertussis toxin was better.