Experimental design.

<p>On days 0–4 and 7–11, BALB/c mice were daily received PBS, recombinant or wild-type <i>L. lactis</i> via the oral route. On days 17, 24 and 31, mice underwent intraperitoneal (i.p.) injection sensitization with the mixture of Der p2/Alum or sterile PBS. From day 39 to 43, all groups were inhalation challenged with aerosolized HDM allergen over a 45-min period. Positive and Negative group served as positive and negative control in this study, respectively.