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 interleuk in (IL)-12 on a murine model of asthma induced by Dermatophagoides pteronys sinus-derived Der p 1 allergen. C57BL/6 mice immunized with Der p 1 allerge n adsorbed to alum/pertussis toxin developed a T-helper type 2 (Th2)-domina nt immune response characterized by the presence of IgE antibody, airway eo sinophil infiltration and increased production of Th2 cytokine. Intraperito neal injection of IL-12 (1 or 0.1 mu g per day) for 5 days (day - 1 to + 3) simultaneously with each immunization, inhibited the production of IgE and IgG(1) antigen-specific antibodies, whereas production of IgG(2a) was stro ngly enhanced. In addition, mice receiving both doses of IL-12 showed a str ong inhibition of IL-5 but up-regulation of IFN-gamma production by spleen cells stimulated with antigen. Administration of IL-12 also prevented antig en-induced eosinophil infiltration into the bronchoalveolar area in a dose- dependent manner and the primary inflammatory mediator serotonin in broncho alveolar lavage (BAL) fluids was also reduced significantly. Taken together , the data indicate that IL-12, has a potent immunomodulatory effect on hou se-dust-mite-induced allergic disorders and may be used as an efficient age nt for immunotherapy.