Guinea pig asthma induced by red soft coral (Dendronephthya nipponica) inhalation

Spiny lobster fishermen on the Pacific coast of Miyazaki Prefecture in Japan develop bronchial asthma due to occupational sensitization to red soft coral (Dendronephthya nipponica). To assess the role of sensitization in the development of bronchial hyperresponsiveness and the relationship between bronchial responsiveness and bronchial inflammation, we established a guinea pig model of red soft coral induced asthma. Twenty-four guinea pigs were intramuscularly immunized with a priming dose of red soft coral, 5 OD280 (15 mg protein) per 0.5 ml, and 0.5 ml complete Freund's adjuvant on day 1. Booster doses were repeated on day 15. By day 43 all sensitized animals showed high hemagglutination titers against red soft coral conjugated sheep erythrocytes and high IgG1 titers by passive cutaneous anaphylaxis. On day 43, the animals were challenged by inhalation of red soft coral extracts, 20 OD280 for 30 min. The respiratory resistance was monitored by the oscillation method. The respiratory resistance increased immediately upon inhalation in all sensitized animals and returned to baseline within 4 h. The bronchial reactivity to acetylcholine, measured 6 h after red soft coral inhalation in the sensitized animals when the respiratory resistance was returned to baseline, increased significantly (p < 0.05) as compared with the values measured 24 h before inhalation. The acetylcholine response measured 30 h later did not differ from preinhalation levels. There was a significant difference in the number of eosinophils (p < 0.001) in lamina propria and epithelium and of lymphocytes (p < 0.05) in the lamina propria 6 h after inhalation in the sensitized animals.(ABSTRACT TRUNCATED AT 250 WORDS)