Administration of Interleukin‐12 Prevents Mite Der p 1 Allergen‐IgE Antibody Production and Airway Eosinophil Infiltration in an Animal Model of Airway Inflammation

The aim of the present study was to examine the in vivo effect of interleukin (IL)‐12 on a murine model of asthma induced by Dermatophagoides pteronyssinus‐derived Der p 1 allergen. C57BL/6 mice immunized with Der p 1 allergen adsorbed to alum/pertussis toxin developed a T‐helper type 2 (Th2)‐dominant immune response characterized by the presence of IgE antibody, airway eosinophil infiltration and increased production of Th2 cytokine. Intraperitoneal injection of IL‐12 (1 or 0.1 μg per day) for 5 days (day − 1 to + 3) simultaneously with each immunization, inhibited the production of IgE and IgG1 antigen‐specific antibodies, whereas production of IgG2a was strongly enhanced. In addition, mice receiving both doses of IL‐12 showed a strong inhibition of IL‐5 but up‐regulation of IFN‐γ production by spleen cells stimulated with antigen. Administration of IL‐12 also prevented antigen‐induced eosinophil infiltration into the bronchoalveolar area in a dose‐dependent manner and the primary inflammatory mediator serotonin in bronchoalveolar lavage (BAL) fluids was also reduced significantly. Taken together, the data indicate that IL‐12 has a potent immunomodulatory effect on house‐dust‐mite‐induced allergic disorders and may be used as an efficient agent for immunotherapy.