Fig. 1

Experimental design. Guinea pigs were sensitized by intraperitoneal (0.5 mg/ml) and subdermal (0.5 mg/ml) injections with a combination of ovalbumin (60 μg/ml) and 1 mg/ml aluminium hydroxide dispersed in physiological saline solution (black squares). Eight days later, the sensitization was reinforced with ovalbumin aerosol administration for 5 min (3 mg/ml; black triangle). From day 15 onward, guinea pigs were challenged for one minute with ovalbumin aerosol every 10 days; 1 mg/ml was used for the first challenge, and 0.5 mg/ml was used for the subsequent challenges (black circles). At the third challenge, dose–response curves in response to histamine were generated, and tissue acquisition was performed. The animals in the control group (open figures) received physiological saline solution instead of ovalbumin