Investigation of mucosal immunisation in pulmonary clearance of Moraxella (Branhamella) catarrhalis

Moraxella (Branhamella) catarrhalis is a common cause of otitis media in ch ildren and respiratory infection in adults with chronic obstructive pulmona ry disease. To identify immune responses that may facilitate the developmen t of a mucosal vaccine, a mouse model to study pulmonary responses was esta blished. Regimes involving intra-Peyer's patch, intratracheal and intranasa l routes of immunisation with killed M. catarrhalis were investigated. A mu cosal immunisation regime of a primary intra-Peyer's patch immunisation wit h an intratracheal boost resulted in significantly enhanced pulmonary clear ance of bacteria compared to controls following an intratracheal challenge with live bacteria. Additional intratracheal boosts did not induce further enhancement of clearance. Intra-Peyer's patch immunisation alone, intratrac heal and intranasal immunisations did not induce enhanced clearance. The le vels of specific IgG and IgA in serum and bronchoalveolar lavage fluid corr elated with pulmonary clearance. The present study showed that mucosal immu nisation induced enhanced pulmonary clearance of M. catarrhalis following l ive bacterial challenge. This mucosal immunisation model has demonstrated t hat a mucosal vaccine, particularly an oral vaccine, would be feasible. (C) 1999 Elsevier Science Ltd. All rights reserved.