Figure 1. Experimental design used to study the effect of nasal exposure to ovalbumin in mice.

BALB/c mice (11–13 per group) were sensitized by intranasal administration of 100 µg of ovalbumin in 20 µl PBS in the absence of adjuvants 5 times a week for 2 weeks. After that, mice were challenged by intranasal administration of same dose of ovalbumin two times a week for 6 weeks. As a control, mice were treated with PBS with the same protocol. Two days after the last challenge, mice were sacrificed for obtaining the NAL fluids and tissue samples.