Objective To investigate the efficacy and mechanism of subcutaneously given recombinant Der p 2 entrapped PLGA nanoparticles(DEPN) on mouse model with allergic airway inflammation.Methods 40 BALB/c mice were randomly divided into 5 groups,group A(normal control) were treated with saline(100 ?l) all the time,groups B,C,D and E were sensitized intraperitoneally with crude dust mite extracts(10 ?g) and then subcutaneously treated respectively with PBS(100 ?l),2 mg empty PLGA(EP),100 ?g rDer p 2,and 2 mg DEPN(loaded with 100 ?g rDer p 2) for 3 times,once per day,followed by intranasal challenge of 50 ?g rDer p 2.One day post challenge,mice were sacrificed and bronchoalveolar lavage fluid(BALF) was collected.Number of the total cells and eosinophils was determined,and airway inflammation and mucus secretion were analyzed by haematoxylin and eosin(H&E) staining and periodic acid-Schiff(PAS) staining.Level of cytokines in the supernatant of splenocyte culture was assayed by ELISA.Level of rDer p 2 specific IgG2a and IgE in the sera was determined by ELISA.Results The lung histology showed development of eosinophil infiltration in the airway of mice in groups B and C.The lung inflammation and mucus secretion in groups D and E were significantly alleviated than that of groups B and C.Number of total cells(63.50?5.12) andeosinophils(15.32?3.04) in BALF decreased in group B.Compared with group B,the number of total cells in groups D(55.3?5.20) ? 104 /ml and E(41.00?4.91) ?104 /ml greatly decreased(P