[Effect of Lep d2 from Lepidoglyphus destructor as a vaccine for specific immunotherapy in murine with asthma].

Objective: To assess the effect of Lep d2 from Lepidoglyphus destructor as a vaccine for specific immunotherapy on murine model of asthma.

Methods: Thirty BALB/c mice (SPF) were randomly categorized into a PBS group, an asthma group, and a Lep d2 SIT group. The mice in the asthma group and Lep d2 SIT group were sensitized by intraperitoneal injection with extracts of dust mites on Days 0, 7th, and 14th, while those in the PBS group were injected with PBS. From the 21st day, the asthma group and Lep d2 SIT group exposed to the extracts of dust mites were stimulated by aerosol inhalation for 7 successive days. During the period of the 25th-27th Day, the mice in Lep d2 SIT group were injected intraperitoneally with Lep d2 allergen for SIT 30 min before nasal inhalation, whereas the PBS group and asthma group were treated with only PBS. Twenty-four hours after the final inhalation, all the mice were sacrificed, the bronchoalveolar lavage fluids (BALFs) were collected. The levels of IFN-γ, IL-5 and IL-13 in the BALF and the supernatant of splenocyte culture solution (SSCS) as well as the levels of specific IgE (sIgE) and sIgG2a in the sera were detected by ELISA. The lung tissues of the mice in the above 3 groups were stained by haematoxylin and eosin (H&E) and observed by a microscope.

Results: The symptoms of acute asthma attack were observed in the mice of the asthma group and Lep d2 group, but not in the PBS group. The allergic inflammation changes in lung in the Lep d2 SIT group were significantly alleviated compared with those in the asthma group. The concentrations of IFN-γ in BALFs and SSCS of the mice in the Lep d2 SIT group were significantly higher than those in the asthma group (both P < 0.01), while the levels of IL-5 and IL-13 in the former group were significantly lower than those in the latter group (all P < 0.01). Meanwhile, the level of sIgE of mice in the Lep d2 SIT group was significantly lower than those in the asthma group (P < 0.01), while the level of sIgG2a of mice in the former group was higher than those in the latter group (P < 0.01).

Conclusion: Lep d2 allergen as a vaccine can alleviate the allergic symptoms in the lung of mice effectively after allergen specific immunotherapy.