[Analysis of sensitization effect of chimeric allergen TAT-IhC-R8 derived from major allergen group 1 genes of dust mites].

Objective: To explore the sensitization effect of allergen TAT-IhC-R8, derived from major allergen group 1 genes of dust mites.

Methods: Forty BALB/c mice were randomly divided into 4 groups, namely PBS group, ovalbumin (OVA) group, R8 group and TAT-IhC-R8 (TIR8) group, 10 mice each group. All the mice in OVA, R8 and TIR8 groups were treated with corresponding allergens (10 µg/ml) on the 0, 7th and 14th day by intraperitoneal injection and nebulized inhalation on day 21 with the concentration of 30 min/d for 7 days. The mice in PBS group were treated with PBS. Twenty-four hours after the last challenge, all the mice were sacrificed, their bronchoalveolar lavage fluids (BALFs) and sera were collected and their spleen cells were cultured. ELISA was performed to detect the levels of IFN-γ and IL-13 in BALFs and supernatants of cultured splenocytes (SCSs) of the mice, as well as the levels of allergen-specific IgE (sIgE), IgG, and IgG2 in their sera. The number of white blood cells and eosinophils in BALF were calculated. In addition, the airway inflammation and mucus secretion were analyzed by haematoxylin and eosin (H&E) staining.

Results: Compared with the PBS group, the lung inflammations of mice in the OVA, R8 and TIR8 groups were observed obviously, including inflammatory infiltration, bronchial epithelial cell breakage and falling off, as well as vasculitis. The numbers of the total white blood cells and eosinophils in BALF of mice in the TIR8 group were significantly more than those in the OVA and R8 groups (all P < 0.01). The IL-13 levels in BALFs and SCSs of mice in the TIR8 group were significantly higher than those in the OVA group and R8 group (all P < 0.01). However, the level of IFN-γ of mice in the TIR8 group was lower than those in the latter 2 groups (all P < 0.01). In addition, the levels of sera sIgE and IgG of mice from the TIR8 group were significantly higher than those in the OVA group and R8 group (all P < 0.01), but the level of IgG2a of the former was significantly lower than those of the latter groups (all P < 0.01).

Conclusions: TAT-IhC-R8 can effectively stimulate lung inflammations of mice, and its sensitization effect is better than R8's.