Inhibition of accumulation of mast cells in the airways and asthma attack by rIL-12 and rIFN-γ

Objective To investigate the effects of rIL-12 and rIFN-γ on allergen-provoked mast cells accumulation in the airways of guinea pigs. Methods Dunkin Hartley guinea pigs were randomly divided into four groups: Asthma group(group A), rIL-12 group(group B),rIFN-γ group(group C)and normal control group (group D). Guinea pigs in group A, B and C were sensitized with 100 mg/mL ovalbumin. Five weeks following injection, animals in group A, B and C were given bronchial challenge with ovalbumin. Inhibitory study was performed by pre-inhalation of saline, rIL-12 and rIFN-γ into group A, B and C animals, respectively at 24, 12 and 2 hours before challenge. Bronchial and lung tissues were removed from guinea pigs 1 hours following bronchial challenge. Bronchial and lung specimen were stained with anti-human tryptase antibody (AA1) by using immunohistochemical technique. Only positively stained cells were counted. Results All animals in group A showed positive reaction to bronchial challenge, whereas animals in group B, C and D did not. There were about 3.0 fold more mast cells in the bronchial tissues of group A animals than that in group B, C and D animals. Conclusion Inhalation of rIL-12 and rIFN-γ was able to inhibit mast cell accumulation and asthma attack in the allergen challenged airways of guinea pigs.