The Antiasthma Effect of Neonatal BCG Vaccination Does Not Depend on the Th17/Th1 but IL-17/IFN-γ Balance in a BALB/c Mouse Asthma Model

Objective This study aimed to determine whether the protective effects of the Mycobacterium bovis Bacillus Calmette–Guérin (BCG) vaccination on allergic asthma are associated with the T helper (Th) 17/Th1 balance in a murine asthma model. Methods BALB/c neonates were vaccinated with BCG on the first day after birth, sensitized with ovalbumin, and then challenged with allergen. The resulting airway inflammation and responsiveness were measured. The levels of IL-17 and interferon (IFN)-γ in BALF and ratio of Th17/Th1 were investigated. Results We found that although BCG neonatal vaccination inhibited airway hyperresponsiveness and inflammation following allergen challenge in a BALB/c mouse asthma model, reduced levels of Th2 cytokines were not observed. However, BCG neonatal vaccination reduced IL-17 production and increased IFN-γ production in both the bronchoalveolar lavage fluid and the lung lymphocytes in asthmatic mice. Conclusion The antiasthma effects of neonatal BCG vaccination reversed the IL-17/IFN-γ imbalance in a murine asthma model but did not depend on modifying the Th17/Th1 balance.