To assess the immunotherapy efficacies of recombinant vaccines containing T-cell epitopes derived from group I and allergens from Dermatophagoides pteronyssinus (Der p1, Der p2). Forty female BALB/c mice were randomized into groups of negative control (PBS group), positive controls (Asthma group), immunotherapy with rDer p1 and rDer p2 protein suspension (rDer p1/rDer p2 group) and specific immunotherapy with fusion peptide T1-8 (T1-8 group). Asthmatic mouse models were initially established with the crude extract from house dust mites (HDM), and PBS models were solely treated with PBS buffer. The two treatment groups were managed with corresponding protein via subcutaneous injection at the back 30 minutes before inhalation sensitization from day 25 to 27. Twenty-four hour following the final inhalation challenge, sera, bronchoalveolar lavage fluid (BALF) and the supernatant of splenocyte cultures (SSCC) were collected in each group of mice. ELISA was used to assay the levels of IFN-γ, IL-4, IL-10 and IL-17 in the BALF and SSCC, as well as serum levels of specific IgE, IgG1 and IgG2a. The lung tissue sections were stained with haematoxylin and eosin (H&E) for pathological examination. ELISA detection revealed reduced levels of IL-4 and IL-17 in the BALF and SSCC, yet increased levels of IFN-γ and IL-10, and decreased specific serum IgE and IgG1, yet increased serum IgG2a in T1-8 group and rDer p1/rDer p2 group than asthma group (P<0.05). T1-8 group had lower IL-4 and IL-17 level and higher IFN-γ and IL-10 level in the BALF and SSCC as well as reduced specific serum IgE and IgG1, yet elevated IgG2a level compared to rDer p1/rDer p2 group (P<0.05). Examination on the lung sections indicated significantly abated pulmonary inflammation, less inflammatory cell infiltration and better remodeled airway epithelia in T1-8 group and rDer p1/rDer p2 group than asthma group. However, the airway epithelium structure T1-8 group and rDer p1/rDer p2 group remained similar to that of PBS group. In Conclusion, The recombinant protein T1-8, has effectively alleviated the allergic inflammation of airways and lungs in the experimental mice, suggesting that this synthetic peptide may be used as candidate vaccines for asthma on allergen-specific immunotherapy basis.
Keywords: Der p1; Der p2; Dermatophagoides pteronyssinus; T cell epitope; specific immunotherapy.