NEW YORK (Reuters Health) - Neonatal vaccination with Bacillus Calmette-Guerin (BCG) provides long-term protection from allergic responses in mice, according to investigators in China.
Previous studies have shown that BCG can inhibit allergic airway eosinophilia and airway hyperresponsiveness in animal models of asthma, the authors explain, but whether neonatal BCG vaccination can modulate allergic airway inflammation in aged animals is not clear.
Dr. Huahao Shen from Second Hospital of Medical School of Zhejiang University, Hangzhou, and colleagues characterized airway inflammation and allergen-specific T-cell responses in mice vaccinated as neonates with BCG and later sensitized and then challenged at various life stages with ovalbumin.
BCG vaccination inhibited ovalbumin-induced airway hyperresponsiveness and airway eosinophilia in early- and late-challenged mice, the authors report in the May issue of Allergy.
Vaccination inhibited mucus overproduction in early-challenged mice but not in asthmatic and aged mice, the report indicates.
BCG immunization shifted the dominant ovalbumin-specific Th2 responses to Th1 responses in younger mice, but not in aged asthmatic mice, the investigators say.
"Our data are consistent with the notion that neonatal vaccination with BCG induces Th1 responses, which subsequently inhibit allergen-specific Th2 responses, leading to the attenuation of allergic airway inflammation," the authors conclude.
"These novel findings suggest that other mechanism(s) may underlie the long-lasting protection of BCG vaccination in aged mice," the researchers add. "Our findings provide a basis for the design of new strategies for the prevention and intervention in human