Abstract:

Objective   To explore the effect of specific immunotherapy with chimeric allergens in murine asthma models, which were derived from the major allergen group 2 genes, Der f 2 and Der p 2, from dust mites. Methods   One hundred and sixty BALB∕c mice were randomly divided into 8 groups, namely PBS group(negative control group), Der f 2 and Der p 2 immunotherapy group (positive control group), asthma group and chimeric allergen immunotherapy groups (divided into four groups: M01, M03, M08 and M10). BALB/c mice were treated with dust mite extract on 0, 7 and 14 day by intraperitoneal injection of allergens and inhaled aerosol on day 21 for 7 days; Before inhalation in immunotherapy groups (including positive controls) in the 25d - 27 d, specific allergen immunotherapy were performed using Der f 2, Der p 2 and chimeric allergens. PBS group were treated with PBS all the time. Twenty-four hours after the last challenge, mice in every group were sacrificed. The lungs were made into slices stained by hematoxylin and eosin in order to observe the pathologic changes in lungs. The bronchoalveolar lavage fluid (BALF) was collected to determine the number of the total cells, neutrophils, lymphocytes and eosinophils by Liu’s staining. ELISA was used to assay the level of cytokines (IL-4, IL-17and IFN-γ) in BALF and in the supernatant of splenocyte culture (SSCC) and the level of allergen-specific IgE, IgG1 in sera. Results   Compared with those in the asthma group, the lung allergic inflammation changes in positive and experimental groups were significantly alleviated. The number of total cells and eosinophils in the above groups greatly decreased, while the level of allergen-specific IgE and IgG1 in sera was significantly lower in the immunotherapy groups (including positive groups) than that in the asthma group. The level of IL-4, IL-17 released from BALF and SSCC in the immunotherapy groups significantly decreased compared with that in the asthma group, and the level of IFN-γ in the immunotherapy groups was significantly higher than that in the asthma group. Conclusion   The chimeric allergens obtained from major allergen group 2 of dust mites can effectively reduce the dust mite-induced lung inflammation in murine asthma models.

Key words: Mites; Asthma; Immunotherapy; Mice， inbred BALB C；Genes