OBJECTIVETo identify the immunological characteristics of the recombinant major pollen allergen pTSX2 of Humulus scandens and evaluate its safety in immunotherapy of allergic asthma in mice.

METHODSWestern blotting was used to characterize the immunological properties of pTSX2, and its immunogenicity in normal mice was evaluated by detecting sIgG and sIgE levels. The mouse models of allergic asthma were immunized with pTSX2 and examined for sIgE and sIgG levels, total cells and eosinophils percentage in BALF, interleukin-4 (IL-4) and interferon-γ (IFN-γ) levels in BALF and spleen homogenate, and changes in lung pathologies.

RESULTSWestern blotting showed that pTSX2 reacted with the majority (about 70%) of sera from patients allergic to Humulus pollen. In normal mice, pTSX2 mainly induced the production of sIgG. In mouse models of allergic asthma, intervention with pTSX2 caused a significant reduction of sIgE and an increase of sIgG (P<0.05), significantly decreased the total cells and eosinophils in BALF (P<0.05), obviously lowered IL-4 but increased IFN-γ in BALF and spleen homogenate (P<0.05), and diminished inflammatory cell infiltration and percentage of eosinophils in the lung tissues.

CONCLUSIONSpTSX2 shows a definite therapeutic effect and safety in the treatment of allergic asthma in mice possibly by inhibiting sIgE and inducing sIgG production, suppressing airway allergic inflammation and regulating the balance between Thl and Th2.