BCG infection during pre-sensitization or even post-sensitization inhibits airway sensitivity in an animal model of allergic asthma.
The objective of this study is to investigate whether BCG infection before, during or after sensitization suppresses allergen-induced airway hyperresponsiveness and eosinophilic inflammation in allergic asthma rats, and to determine the required dose of BCG to induce such an inhibition. Eighty-seven Sprague-Dawley (SD) rats were sensitized and provoked with ovalbumin (OA). A pretreatment of 6 x 10(4) or 6 x 10(5) colony forming units (CFUs) of BCG or saline was done at four different times: 3 days before sensitization, at sensitization, 3 days before provocation, or at provocation. The assessment of tracheal smooth muscle (TSM) responsiveness to electrical field stimulation or acetylcholine (ACh) and bronchoalveolar lavage (BAL) were performed 1 day after OA provocation. Doses of 6 x 10(4) CFUs inhibited TSM sensitivity of rats infected 3 days before sensitization or at sensitization, but not 3 days before provocation or at provocation. However, doses of 6 x 10(5) CFUs significantly inhibited not only the airway eosinophilia of rats infected 3 days before sensitization or at sensitization, but also the TSM sensitivity of rats infected 3 days before provocation or at provocation. In conclusion, BCG infection suppresses the development of sensitivity of airway smooth muscle and airway eosinophilic inflammation in allergic asthma rats. Furthermore, a relatively high dose of BCG infection inhibits airway sensitivity, even after allergen sensitization.
Koh
Y I
YI
Department of Internal Medicine, Chonnam National University Medical School, Kwangju, Korea.
Choi
I S
IS
Park
S C
SC
Kang
K W
KW
D000818:Animals; D001249:Asthma / Q000276:immunology*; D001500:BCG Vaccine / Q000276:immunology*; D004195:Disease Models, Animal; D004804:Eosinophils / Q000276:immunology; D007958:Leukocyte Count; D008168:Lung / Q000276:immunology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014611:Vaccination
D001500:BCG Vaccine