Suppressive Effect of BCG on Ovalbumin-induced Early- and Late- Airway Reactions in Sensitized Rats

Choi, Inseon S; Kim, Won Yeong; Koh, Youngil I

Abstract

The prevalence of bronchial asthma has been increased during the last two decades, which is a worldwide phenomenon. One possible explanation for this phenomenon is that decrease in infection results in decrease the production of Th1 type cytokines, which in turn increase Th2 type cytokines and allergic diseases. BCG vaccine is known to be a potent inducer of Th1-type response. We have shown in our previous studies that BCG vaccine suppresses the development of airway inflammation and tracheal muscle hyperresponsiveness, and the increase of interleukin-4 concentration in bronchoalveolar lavage fluid in ovalbumin (OVA) - sensitized rats, and the BCG effects occur in the provocation stage as well as the sensitization stage. The purpose of this study was to investigate whether BCG reduces an allergen-induced early- and late- airway reaction in an animal model of allergic asthma. OVA- sensitized rats (10 microgram subcutaneous injection 14 days before provocation, n=12) developed significantly higher enhanced pause (Penh) during the first 30 minutes (early airway reaction, EAR) and 2~4 hours (late airway reaction, LAR) following 5% OVA aerosols inhalation than normal control rats (n=12). However, OVA-induced Penh changes (EAR and LAR) were not significantly different in rats pretreated with BCG(1 x 106, intraperitoneally) 3 days prior to sensitization (n=12) or provocation (n=12) compared to rats without BCG-pretreatment. In conclusion, BCG vaccine pretreatment was not effective in preven tion of OVA-induced airway reaction in this model.