Abstract
The mucosal surface of the respiratory tract is equipped with the mucosal immune system. Secretory IgA plays an important role in this immune system and protects the host from microbial invasion via the respiratory tract. In the present study, we examine the mucosal immune responses in the respiratory tract against Haemophilus influenzae and discuss the efficacy of administering a mucosal vaccine by aerosol. Animal studies in mice have demonstrated that antigen-specific IgA responses were induced in the upper and lower respiratory tracts by intranasal as well as intratracheal immunization. The results suggest that aerosol vaccination might be useful for the prevention of respiratory tract infections. However, immune tolerance induced by longterm or frequent mucosal vaccination should be considered while developing vaccines for aerosol application.
